# Gaggia Classic Preheat mod



## mrmike1

After decided to wait for a new machine, I decided to research/ pursue some upgrade on the Classic. I've got the Auberins PID, brass dispersion plate, OPV and nake pf done. I guess the last thing would be to preheat the water before it goes to the boiler.

The easier... (from what I found) option would be to attach copper tubing between the OPV and boiler. As this tubing is wrapped around the boiler, it acts like an hx machine bringing better stability. I would prefer this option rather than buying a Krups and taking out the thermoblock and installing into the Gaggia.

Now the fun part.... creating a plan and sourcing the parts. Ebay is useful and I have a Screwfix near by. I'll need to find some manual as well regarding the sizes.

At easiest, I think, would be to buy the right size copper tubing with the proper fixture. Remove the boiler (need to research that, but I suspect an allen key will do the job), wrap tubing around it, insulate as well (don't know what to use), put boiler back in, and finally connect between to OPV.

Sounds easy, but will probably take all weekend.

And that last bit things change so will the parameters on the PID need changing as well? How would I do that?

I'll document the entire process and either fail or succeed. I hope the former!


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## Kyle548

It's very hard and will take hours of your time.

I have some copper tubing, roughly wound to the right shape, if you want it.

Getting fittings small enough will be the clencher; only parts easily sourceable are hydraulic parts, and they tend to be rated to about 8-10 bar.

I have a few of those too. Your best bet would be to have those and find tubing to fit.


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## mrmike1

Did you do this mod on your old Gaggia?

Let me know what else I would need.


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## Kyle548

I tried, but in the end couldn't be bothered.

You need some plumbers tape, some microbore copper tubing and some fittings.

I'd recommend a tube bender too, you need some really tight turns.

You will prob need to adjust the pressure after you do it.

To be honest though, I'm not sure how the mod would effect pressure - the pump is calibrated to pump cool water - the less dense hot water is harder to pump.

Try filling your tank with boiling water - the machine won't come up to pressure at all.


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## mrmike1

Ill have a go at it as long as youll have a go at my sous vide pid


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## Kyle548

I'll try have a look at it.


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## mrmike1

Just realized that the OVP is attached to the boiler. How do you get around that?


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## mrmike1

Guess you can't. So really, the OPV will be dumping water that was heated by the copper tubing back into the main tank. Will this mod be really worth it?


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## Kyle548

mrmike1 said:


> Guess you can't. So really, the OPV will be dumping water that was heated by the copper tubing back into the main tank. Will this mod be really worth it?


Exactly, so you end up with warm water in the tank.

Not sure it makes a huge difference at those levels though, my machine gets really got, sure the tank water must bake.

But I guess, the dynamics of how mine fills are different.

The general consensus with the mod though, is that it's too hard that unless your seriously handy or a hobbyists who's into that sort of thing, it's not really worth it though.


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## marcuswar

Why not just fit an inline OPV (venting back into the tank) before the preheat loop and then adjust the original one attached to the boiler (and the preheat loop) to a higher pressure e.g. the original 15bar. This will effectively by pass it as the first inline OPV will reduce the line pressure to below its activation pressure.


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## mrmike1

My wife and I do enjoy a challenge.


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## mrmike1

If I understand this correctly, the amount of water that brews will be equal to the amount of water that the OPV flushes back to the main tank. 60ml of preheated won't heat the main water tank that much, assuming you have enough there in the first place, due to dilution.

I do think that having the OPV before the loop will lead to a hotter incoming water. Will this one do?

http://www.ebay.co.uk/itm/9-Bar-Over-Pressure-Valve-OPV-suits-Gaggia-Coffee-machine-Maker-1-8-BSP-/400455498326?pt=UK_Homes_Garden_Kitchen_Kettles&hash=item5d3d01fa56


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## mrmike1

Or this http://www.ebay.co.uk/itm/Over-Pressure-valve-OPV-suits-Coffee-Machine-Maker-/400629715839?pt=UK_Homes_Garden_Kitchen_Kettles&hash=item5d4764537f


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## mrmike1

Kyle, what size is the copper tubing you have? I need to draw up a plan and see where I can source the missing pieces from.


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## mrmike1

Just took the cover off the Gaggia. There is a telfon tubing that seems to be attached to the pump and OPV by a compression fitting. Don't know the size. Maybe 1/4inch, or 10mm. Remove that tubing. And run some copper tubing top down counter-clockwise to the OPV valve.


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## Kyle548

The black tubing is to the expansion tube - the clear tubing with a bayonet fit goes from the opv to the tank.

The pump to opv is a not quite 1/4" compression to metric screw fitting.

I have two hydraulic fittings that will fit, but it's hard to get a seal on copper tubing with it.

Everything is metric, so British pipe fittings which are all in British standard sizes just don't fit well.


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## mrmike1

What mm size is it in that case? Ebay sells some 6mm, if its the same size as the Teflon tubing, would a direct swap work?


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## Kyle548

It was 6mm iirc.

http://www.ebay.co.uk/itm/6mm-Stud-1-4-Female-BSPP-Brass-Compression-Fitting-/310329858080?ssPageName=ADME:L:OU:GB:3160

With some tape and a bit of elbow grease, this will fit the inlet and outlet without leaking.

Or it should do, I was trying to build a more complex system with a pressure stat connected to a t coupling and the fitting kept leaking from the compression side.

So your best to get the fitting then find pipe to fit it.

Remember that any considerable changers diameter or too much tube will change the pressure of the system quite a lot.


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## mrmike1

At one point I was thinking about non copper solutions. Braided PVC can take the pressure but is a poor conductor of heat while silicone conducts heat well but can't take the pressure. I think silicone can take heat up to 180C while PVC can only take 65C. Now, this paper suggests very little difference between copper and PVC http://ascpro0.ascweb.org/archives/cd/2010/paper/CPRT192002010.pdf

The only braided silicone I found is this http://www.hoseworld.com/acatalog/FOOD_QUALITY_REINFORCED_SILICONE_HOSE_.html seems a little expensive and the max pressure is 13bar. Silicone is half as conductive as copper.


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## Neill

mrmike1 said:


> At one point I was thinking about non copper solutions. Braided PVC can take the pressure but is a poor conductor of heat while silicone conducts heat well but can't take the pressure. I think silicone can take heat up to 180C while PVC can only take 65C. Now, this paper suggests very little difference between copper and PVC http://ascpro0.ascweb.org/archives/cd/2010/paper/CPRT192002010.pdf
> 
> The only braided silicone I found is this http://www.hoseworld.com/acatalog/FOOD_QUALITY_REINFORCED_SILICONE_HOSE_.html seems a little expensive and the max pressure is 13bar. Silicone is half as conductive as copper.


Have you seen this thread before http://www.home-barista.com/espresso-machines/preheating-incoming-water-on-gaggia-classic-t2794.html


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## mrmike1

I've read it, its actually one of the first which inspired me. The problem is I don't have access to a mill. I do think this one has the cleanest approach.


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## mrmike1

What about using this? It can take the pressure, heat, and can bend. I can't find any thermal properties but frying pans have teflon on them so you could assume it conducts heat well, otherwise we'd never get any cooking. As long as the boiler and coil are insulated, it might work well and be easy to administer. I wonder if I can just swap out the current teflon tubing for a longer one found below.

http://www.ebay.co.uk/itm/PTFE-Tube-Tubing-8mm-OD-6mm-ID-1-METRE-/260984639838?pt=LH_DefaultDomain_3&hash=item3cc3e5915e


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## mrmike1

After thinking about this, I'm going to attempt a copper tube with no OPV (I just can't find one to buy). I'll need fittings on both sides, the copper tube, and a tube bender.


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## mrmike1

Just dropped a supplier regarding an OPV value. Awaiting there response. Anyway, I'm reading several forums and now confused. Some say the fittings are 6mm, while others say they are 1/4 inch. So if I get a 1/4inch copper tube. What will be the two fittings I need. Fitting A: 1/4inch compression to ? and fitting B: 1/4inch compress to ?


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## Kyle548

Basically, this is the problem you will have.

The fittings should technically be in mm, since the Gaggia using M thread sizes for everything, British pipe fittings are all in inches though, with a different pitch.

So it's hard to find anything that will fit.

The pipe can be any size you like though, as long as the fitting will seal onto it - the important thing is getting a fitting that will match the Classic.

I think, actually, the fittings on the classic are 3mm, but 1/8bsp will fit and sort of seal with lots of PTFE tape, so you need to get a 1/8bsp to 1/4 female stud to compression fitting.

http://www.ebay.co.uk/itm/Air-Water-Pneumatic-Tube-Compression-F-Stud-1-8bsp-6mm-/150632975694?ssPageName=ADME:L:OU:GB:3160

This item will defiantly fit and seal on the classic, but it won't fit on 1/4" pipe, as 1/4" is slightly bigger than 6mm....


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## El carajillo

Do not try using 6 mm pipe and 1/4 " fittings and packing wit P T F E tape. 1/4 inch is 6.35 mm olives will not compress and accommodate this variation/difference, you will find small bore copper is 6 mm and is in various hardness grades.

NB 6 mm half hard copper pipe has a SAFE working pressure of 116 bar at 100 degrees C. If it is softened by soldering /heat application

the SAFE working pressure is 89 bar at 100 deg/C.

Make sure of the grade of pipe you are using, there is a softer grade from the half hard but it's pressure capacity is much less than Half hard.









Something else to bear in mind is that unless you get "medical grade pipe" which is steam cleaned an sterilised, you will need to thoroughly clean the oil and "drawing" residue out of the pipe before you fit to machine.!!!


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## froggystyle

Are you starting to think this wasnt a good idea yet Mike?


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## mrmike1

I'm determined! Lol


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## froggystyle

Stick with it pal, i am interested to see how it works out, plus if it brings a big benefit to the classic...


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## froggystyle

I am doing another project on the classic, back up my dads tonight to use his vast array of tools in his man shed.

Nearing part completion so may post some pics soon.


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## mrmike1

Wicked, ive had a break through! Ill post shortly.


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## mrmike1

El carajillo said:


> Do not try using 6 mm pipe and 1/4 " fittings and packing wit P T F E tape. 1/4 inch is 6.35 mm olives will not compress and accommodate this variation/difference, you will find small bore copper is 6 mm and is in various hardness grades.
> 
> NB 6 mm half hard copper pipe has a SAFE working pressure of 116 bar at 100 degrees C. If it is softened by soldering /heat application
> 
> the SAFE working pressure is 89 bar at 100 deg/C.
> 
> Make sure of the grade of pipe you are using, there is a softer grade from the half hard but it's pressure capacity is much less than Half hard.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Something else to bear in mind is that unless you get "medical grade pipe" which is steam cleaned an sterilised, you will need to thoroughly clean the oil and "drawing" residue out of the pipe before you fit to machine.!!!


Thanks for the advice! Ill keep it in mind


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## mrmike1

Got an email back regarding the OPV valve. Seller said doesn't know and his OPV works with fluid-tech pumps. I have decided not to use the OPV as it will be too much hasle, unless someone can offer an idea where to buy one.


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## mrmike1

I finally found the fitting. 10GPB each (ouch!) http://www.beaumanor.com/Products/002100050029000d/P-GAV6LM

If I got this right, I need two of these (one for the pump and one for the boiler) and 6mm copper tubing. I can also get a 6mm compression elbow to get better access to the the boiler.


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## mrmike1

I'm revisiting the OPV again. If I buy this OPV http://www.ebay.co.uk/itm/Adjustable-Over-Pressure-Valve-OPV-suit-Gaggia-Coffee-Machine-Maker-/161002343592?pt=UK_Homes_Garden_Kitchen_Kettles&hash=item257c7ccca8

I should be able to connect with a 6mm compress tee and a 6mm to 1/4inch female. Sounds simple?


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## mrmike1

Yes, I found http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=6_18_170_294&products_id=1746&zenid=b79ec111780318377975c01654019f32 for 5GBP!

I will do a summary page before I order everything. Looks very promising! Thanks for all the help, I know, this tread is a mess with me jumping from one idea to the next.


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## mrmike1

Regarding the OPV valve.. it says its 1/4 inch.. does that mean I get a 1/4bsp female or 1/8bsp female?


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## mrmike1

The final list. Can someone check if I got all the sizes right?

Basically, the setup will like this

Pump to M10x1.0 female/ 6mm compression.

6mm copper tube

6mm compression tee

6mm copper tube to 6mm compression/ 1/8bsp to OPV

6mm copper tube (wraps around tank)

6mm compression/ M10x1.0 female to boiler

I plan to increase the stock OPV back to 15 and regulate according to new OPV. All in all, it should work however I'm afraid I've got some sizes wrong. I'm still confused on the difference between BSP and imperial.

Copper tubing 3 meters 11.19 http://www.ebay.co.uk/itm/NEW-6mm-microbore-copper-plumbing-pipe-tube-x-1-Metre-/110522133527?pt=UK_DIY_Materials_Plumbing_MJ&hash=item19bba1ec17

Tube bender 5.72 http://www.ebay.co.uk/itm/180A-MINI-PIPE-BENDER-PLUMBING-FOR-6MM-8MM-10MM-COPPER-TUBE-/331198934531?pt=UK_DIY_Materials_Plumbing_MJ&hash=item4d1cfeae03

Tube cutter 1.90 http://www.ebay.co.uk/itm/New-Mini-Pipe-Cutter-3mm-22mm-1-8in-7-8in-Copper-Vinyl-Brass-Tube-/131120075557?pt=UK_DIY_Materials_Plumbing_MJ&hash=item1e875d9325

6mm tube x M10.10 female 2 10.00 http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&products_id=1746

6mm compression elbow 2.74 http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=30_32_69_382&products_id=2043

6mm compression tee 3.30

http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=30_32_69_431&products_id=2432

Inline OPV 19.84 http://www.ebay.co.uk/itm/Adjustable-Over-Pressure-Valve-OPV-suit-Gaggia-Coffee-Machine-Maker-/161002343592?pt=UK_Homes_Garden_Kitchen_Kettles&hash=item257c7ccca8

Clear PVC tubing 1.95 http://www.ebay.co.uk/itm/PVC-Tube-Clear-FLEXIBLE-Plastic-Hose-Pipe-Fish-Pond-Car-Aquariums-Air-line-/151164019758?pt=UK_Pet_Supplies_Fish&var=&hash=item233213e42e

Female 1/8BSP to 6mm compression 1.69 http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=30_32_69_432&products_id=2439

This last link is what gave me inspiration. Also, many thanks to all who have helped me on this journey so far.

http://coffeegeek.com/forums/espresso/machines/214679?LastView=1391893238&Page=2


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## El carajillo

mrmike1 said:


> The final list. Can someone check if I got all the sizes right?
> 
> Basically, the setup will like this
> 
> Pump to M10x1.0 female/ 6mm compression.
> 
> 6mm copper tube
> 
> 6mm compression tee
> 
> 6mm copper tube to 6mm compression/ 1/8bsp to OPV
> 
> 6mm copper tube (wraps around tank)
> 
> 6mm compression/ M10x1.0 female to boiler
> 
> I plan to increase the stock OPV back to 15 and regulate according to new OPV. All in all, it should work however I'm afraid I've got some sizes wrong. I'm still confused on the difference between BSP and imperial.
> 
> Copper tubing 3 meters 11.19 http://www.ebay.co.uk/itm/NEW-6mm-microbore-copper-plumbing-pipe-tube-x-1-Metre-/110522133527?pt=UK_DIY_Materials_Plumbing_MJ&hash=item19bba1ec17
> 
> Tube bender 5.72 http://www.ebay.co.uk/itm/180A-MINI-PIPE-BENDER-PLUMBING-FOR-6MM-8MM-10MM-COPPER-TUBE-/331198934531?pt=UK_DIY_Materials_Plumbing_MJ&hash=item4d1cfeae03
> 
> Tube cutter 1.90 http://www.ebay.co.uk/itm/New-Mini-Pipe-Cutter-3mm-22mm-1-8in-7-8in-Copper-Vinyl-Brass-Tube-/131120075557?pt=UK_DIY_Materials_Plumbing_MJ&hash=item1e875d9325
> 
> 6mm tube x M10.10 female 2 10.00 http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&products_id=1746
> 
> 6mm compression elbow 2.74 http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=30_32_69_382&products_id=2043
> 
> 6mm compression tee 3.30
> 
> http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=30_32_69_431&products_id=2432
> 
> Inline OPV 19.84 http://www.ebay.co.uk/itm/Adjustable-Over-Pressure-Valve-OPV-suit-Gaggia-Coffee-Machine-Maker-/161002343592?pt=UK_Homes_Garden_Kitchen_Kettles&hash=item257c7ccca8
> 
> Clear PVC tubing 1.95 http://www.ebay.co.uk/itm/PVC-Tube-Clear-FLEXIBLE-Plastic-Hose-Pipe-Fish-Pond-Car-Aquariums-Air-line-/151164019758?pt=UK_Pet_Supplies_Fish&var=&hash=item233213e42e
> 
> Female 1/8BSP to 6mm compression 1.69 http://www.fephydraulics.co.uk/online_shop/index.php?main_page=product_info&cPath=30_32_69_432&products_id=2439
> 
> This last link is what gave me inspiration. Also, many thanks to all who have helped me on this journey so far.
> 
> http://coffeegeek.com/forums/espresso/machines/214679?LastView=1391893238&Page=2


B S P stands for British standard pipe (thread), It is a particular thread form used on pipework. As distinct from B S F, BSW, WhITWORTH, METRIC, FINE and COARSE


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## mrmike1

For example, the OVP has a 1/4inch thread. Is that the same at the 1/8BSP on the 6mm compression? Or do I go for the 1/4BSP to 6mm compression?


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## urbanbumpkin

Lovin the mods to the Gaggia Classic. It's a great machine that seems to be geared up for modding.


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## mrmike1

It's a great little machine. I'm just stalling the inevitable though... upgrade to a new machine. The Gaggia has been making me good coffee for several years. When I do finally upgrade the machine, a small part of me will always remember the classic.

I already have the PID, steam wand, brass dispersion plate, LM basket, naked pf.... and hopefully this rather soon.


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## froggystyle

You just need some scales built in...

Now where would you find a plan for them eh!


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## mrmike1

Just got an email back from seller. Inline OPV is 1/4 bsp.


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## Neill

This thread makes for interesting reading. I've kinda reached the end of the road with my moding i think. Don't think I could take this on but enjoying following.


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## mrmike1

I bought the OPV, copper tubing, tube cutter, and am awaiting the shipping quote for the fittings. They should be here next week. Many thanks for all the supporters out there!


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## froggystyle

Looking forward to some pics and details of the build!


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## mrmike1

Thanks, I'll keep you guys updated. Hopefully the OPV/ preheat mod works!!


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## froggystyle

Are you fitting a permanent pressure gauge Mike ?


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## mrmike1

No plan. Not sure how I would do it and how to drill hole ino case.


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## froggystyle

I think it goes between the OPV and something else....


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## mrmike1

All parts ordered.


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## El carajillo

I think your biggest problem would be finding somewhere "TO" fit it in the case.

Hole would cut with a good holesaw. ( not a cheap one)


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## froggystyle

http://www.datenklause.de/blog/archives/date/2012/12

Not sure what a pulse damper is!?


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## mrmike1

Do i need brass olives?


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## El carajillo

froggystyle said:


> http://www.datenklause.de/blog/archives/date/2012/12
> 
> Not sure what a pulse damper is!?


Attachment to smooth out the pulses from the "ULKA PUMP" Also smooth's out the pressure to the gauge/prevent needle dancing about.

A smaller version of a fitting used to "damp out shocks" ( water hammer in water pipes)?


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## El carajillo

mrmike1 said:


> Do i need brass olives?


For what ?? They are normally in the fitting when bought ( you can buy them separately / for spares / lost or damaged)


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## mrmike1

I thought they should be included. But learned never to assume. Next week, ill start posting pictures of this mod.


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## froggystyle

El carajillo said:


> I think your biggest problem would be finding somewhere "TO" fit it in the case.
> 
> Hole would cut with a good holesaw. ( not a cheap one)


Nah, drill little holes, then grind it smooth.


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## El carajillo

froggystyle said:


> Nah, drill little holes, then grind it smooth.


Naah too much like hard work!! ( AND WOOF WOOF ROUGH)


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## mrmike1

I want to compare intra-shot temperatures. Is there any easy way of doing it?


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## mrmike1

Copper tubing and tube cutter came. Tube cutter works. Now awaiting for the rest of the fittings. I've decided to use thermal wrap to insulate the boiler as well.


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## mrmike1

Fittings, OPV, and extra tools came. Just waiting for a few more parts and I'm ready to go. I tried the m10x1.0 thread and it worked, so that is the correct size for the pump. Have not had a chance to check the other fitting, but am pretty sure it should be OK.


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## froggystyle

Dont forget the step by step photos Mike!


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## mrmike1

I will. Wont befor a week thoughas am busy. I hope this works.


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## froggystyle

Any joy Mike?


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## mrmike1

I just came back from out of town today. Everything else came in the mail. The 7mm silicone return tube is loose, might have to go for the 6mm OD tube instead. Anyway, I popped the top off and am trying to figure out how to remove the heater connections lol. This will be a lot of work, but am up for the challenge. Once I safely remove the boiler from the machine safely, it should be easy to attach the pipe. I just hope there won't be any leaking compression fittings. Watch this space.


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## mrmike1

Oh, that was easy. The power connections just pop off. Anyway, I'm trying to be extra careful not to damage anything.


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## mrmike1

Epic fail!

I spent about an hour removing the boiler safely. The m10 x1.0 fittings fit. I attached the one to the OPV and compressed the copper tubing to the other end. It was a tight fit but I managed the bend. I went around the boiler 3 times and I accidentally crushed the tubing on a bend. Unsalvagable- so I decide to cut the tube and start again wrapping it around a bottle first. I can't get compression off. Its stuck and I've tried. Looks like I'll need to buy a new fitting.

I might buy another fitting but might wait for help from my dad in-law. This mod is hard because the copper tubing is difficult to get a good bend. I've wasted a lot of money for this mod already and if it doesn't work out, at least I got to enjoy the adventure.

I'll post pictures tomorrow.


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## marcuswar

What exactly do you mean by the compression fixing is stuck? A compression fitting uses an olive around the pipe that is crushed wand crimps onto the pipe when the fitting is tightened up. Since the nut is behind the olive this will effectively mean the nut is now trapped on the pipe. To remove it you need to remove the olive by carefully sawing through it with a hacksaw being very careful not to cut all the way through and nick the pipe.


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## marcuswar

Oh and a trick that can help prevent the copper tube from crushing as you bend it is to fill the tube with dry fine sand. This needs to be very fine and very dry so it can be fully emptied out after bending.


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## Kyle548

marcuswar said:


> Oh and a trick that can help prevent the copper tube from crushing as you bend it is to fill the tube with dry fine sand. This needs to be very fine and very dry so it can be fully emptied out after bending.


I found bending around a can of beans worked perfectly for the classic boiler.

After that, you just need to slacken the bends a little.


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## mrmike1

I can't get to the olive cause the pipe is bent on the other side. The first bend from the OPV to around the boiler is almost 180 degrees. I cut the tube to before the bend begins but it is bent inside the fitting. Thanks for the inspiratino though, I've dug it out and now will attempt to dremel it. That first bend is so difficult, and ideas?


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## froggystyle

Can you take some photos mike, i cant really image what your doing?


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## mrmike1

As you can see, this end is bent. I managed to free the pipe by dremeling it for 15 minutes. Always wear eye protection when doing this. Success! Time for my machine to cool as just made a latte


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## El carajillo

Mike I take it this is bending the new tube to fit??. There are limits as to how tight you can bend, you can try inserting a rod the same size as internal dia where the nut and olive will be + a bit, then use the rod as a lever. the pipe may "cripple/ squash" a little on the bend but nut and olive will work.

If pipe deforms near olive it will not seal no matter how tight you go.


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## froggystyle

Deleted as wrong...


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## mrmike1

After all morning, this is what I have. I had to unscrew the solenoid, OPV, temp stats.


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## mrmike1

Got it all in. Sprung two leaks by the pump fittings. Added teflon tape and leaks stopped. Everything works so far. Checked pressure while on- getting 10 bar on the OPV, no change from previous. I'm about to pull a shot now and see how it goes. What a day!


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## jeebsy

Pulling that first shot is going to be like watch an Apollo mission take off


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## mrmike1

It is loud, but once up to pressure, its not too loud. First latte, very good. Alot sweeter than this mornings- is it placebo? The copper tube gets really hot so I'm sure it is warming the water before getting into the boiler. At the PID, only a 2 degree drop, usually about 5.

I've given up on the new OPV today, but might try at a later time. It won't fit straight in, but I think I found a place for it.


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## mrmike1

Ta daa!









What a day! The work is half done. I still need to insulate the boiler with glass fiber and add the new OPV. I think with the new OPV, I will have perfect temperature stability.


----------



## froggystyle

I would wait for a few days before insulating, just in case anything leaks or splits!


----------



## marcuswar

Looking good mrmike1, you're making me want to get my old Classic out of storage to give it a go







I guess ideally the length of tubing should be calculated to try and hold enough water to pull a full shot i.e. 2 fluid oz's

There's not much room in there to start adding insulation, what type are you thinking of (foam, fibreglass wool) ?


----------



## mrmike1

marcuswar said:


> Looking good mrmike1, you're making me want to get my old Classic out of storage to give it a go
> 
> 
> 
> 
> 
> 
> 
> I guess ideally the length of tubing should be calculated to try and hold enough water to pull a full shot i.e. 2 fluid oz's
> 
> There's not much room in there to start adding insulation, what type are you thinking of (foam, fibreglass wool) ?


The mass of the copper will also stablise temperature. From what I read, the 6mm tube should have about 30ml, maybe less, however the copper tube acts as a heat sink so all should be good.

If I manage the new OPV, I think it will be a great machine.

Loud, but not as loud as I thought it would be.

I'll keep an eye out for leaks in the next few days. If all is well, I might do the OPV this weekend.

I found tape insulation that's made from fibre used for car exhuast, supposoded to boost HP. It was cheap, 2 quid on Ebay. I'll have to take the boiler out again and wrap it. That should dampen some of the sound as well.

Anyway, dead band on the PID is 2 deg every 30 seconds or so. Any suggests on PID settings?


----------



## marcuswar

Wow, exhaust tape that increases your horse power... does it come with some go faster stripes as well









What insulation rating does it have, do you have a link ? I could do with something thin to insulate the brew head feed and return pipes on my ISOMAC Tea. I used silicon foam for the boiler but it's too thick to wrap around the pipes.

Have you retrained the PID since adding the preheat ? If not then you probably should as you will have changed the dynamics of how it heats up and cools down.


----------



## mrmike1

http://www.ebay.co.uk/itm/Performance-Exhaust-Manifold-Downpipe-Insulating-Heat-Wrap-2-/201051718253?pt=UK_WSJL_Wholesale_GL&var=&hash=item2ecf9dc26d Rated to 1000F. Should be good, its thin and easy to manipulate. I was planning on the silicone but thought it wouldn't fit. Only thing they suggest is to wear gloves as the fibre will irritate skin.

I havn't retrained the PID. I'm afraid to auto tune will make things worse. I'm using the Auberins. Do you think I should auto tune or manually change the settings?


----------



## marcuswar

My only experience with a PID is with a cheap Chinese one (£20 off eBay) but yes I would say you should definitely (auto) retrain it. It needs to learn how quickly the boiler now heats up and cools down in order to work out when it should be turning the heating elements on and off to maintain a steady temperature. With the PID I used this training took about 30mins to complete and during this training it would progressively heat the machine up to way past the target set point. I seem to remember that I actually reduced the target set point while training as I became concerned that the overshoot was going to go high enough to blow the thermal fuse.


----------



## mrmike1

I just autotuned it. Took about 3 minutes. Now, no dead band. Also, I wonder if I should lower my set point. I'm currently on 101C.


----------



## froggystyle

Have you tried pulling another shot straight after your first?


----------



## mrmike1

Not yet, as I'm running out of coffee and need to order some today. Hopefully it will last me until the shipment comes. Anyway, pulling a naked shot, temp ranges from 101 to 96 where before it was it was hitting the upper 80's. I'll keep you updated.

With the new OPV, there should be very little range as only cold water is dumped.


----------



## mrmike1

So far, no leaks. PID is tuned. Not the nicest job, but should work. I can't wait for tomorrow's coffee.


----------



## mrmike1

To summarize: A run down on the pre-heat mod

1. Remove boiler including OPV, temp stats, and solenoid. Drain of water.

2. Pre-wrap the tube around a can of beans.

3. Ideally, take steam valve off and slide over the coiled tube, but if you can't take the steam valve off, you'll have to unwrap and rewrap coiled tube (still easier than wrapping around the boiler from a straight tube).

4. Watch out for kinks! No need to put salt in tube, just be careful.

5. Once tube is near where the tube/ OPV connection, use the loose OPV and attach to the tube. Afterwards, you can use the OPV (with tube attached) as a lever.

6. Reattach OPV to boiler (with tube already connected).

7. Now, put entire boiler back into chassis and make sure tube near OPV fits, including the steam copper tubing.

8. Once fit, reattach all connections.

9. Attach pump to tube.

10. All threaded fittings should have teflon tape.

11. Prim boiler and check for leaks.

12. Retune PID.


----------



## marcuswar

Have you fitted a brass dispersion plate ? If not I would recommended fitting one for the ultimate in a stable temperature Classic.


----------



## mrmike1

Oh yes, I do have the brass plate. It made a noticeable difference before this mod. It should even more this mod.


----------



## froggystyle

Not sure what else you can mod!


----------



## marcuswar

Nah... Plenty of mods still left... Just harder...How about fitting an Audrino...

http://www.cyberelectronics.org/?p=315


----------



## froggystyle

ha, yeah maybe a step to far!


----------



## mrmike1

Audrino- my dad has a C/C machine shop in Chicago, and I always thought we can manufacture American made espresso machines using the Audrino controller. Very hard and I don't know anything about design and distribution of said machine.

Just a pipe dream for now.


----------



## marcuswar

I think we are all well beyond a 'step' too far... But yes, that one is definetly one for a serious hacker


----------



## mrmike1

Coffee was very smooth today.


----------



## mrmike1

Just went to turn on the machine and PID says EEEEE. No water leak, need to check PID connections.


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## mrmike1

Manual says EEEE is an input error. Just checked the connections, all seems good. Any ideas?


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## mrmike1

Just pulled the temp probe wires and gave them some slack. Now it works again. They must have been tight.


----------



## mrmike1

Just put the case back on and again EEEE. What gives?


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## marcuswar

maybe a loose wire connection at the PID end ?


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## mrmike1

Just checked... all wires connected. I wonder if the vibration damaged the temp sensor.


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## mrmike1

The sensor cable was wrapped along with some other cable. When I untied it, now it works.


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## marcuswar

Strange, must be interference from being close to a wire carrying 240v. Glad you got it sorted.


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## mrmike1

I hope the problem was that simple. Anyway, I'm trying to set ideal PID settings. The AT doesn't work well, resulting in massive overshoot and extremely long heat time to set point.


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## marcuswar

AT = auto tune? With my cheap PID the Auto Tune took a lot longer than the 3 minutes you mentioned, probably more like 20 to 30 minutes. I'm not sure how it could do it so quickly as it needs to fully heat up and cool down multiple times to tune it properly. Is there a "clear" option to clear old settings , or maybe a "Full" Auto Tune option ?


----------



## mrmike1

AT= auto tune. It took about 10 minutes. 3 cycles from 90 degrees.

The main issue is when do I auto tune? Once I'm at the set point or from cold, do I pull a shot in the cooling phase of AT?


----------



## marcuswar

If it were me I'd do the auto tune from cold. Pull a shot during AT, why would you do that? My understanding is that the auto tune works out how quickly the boiler heats up and cools down so it can predict when to turn on the heating elements in order to maintain the temperature. If you start pulling shots in the middle of it then you will artificially skew the tuning figures and have an inverse effect on its ability to maintain a steady temperature. You should leave the PID to fully do it's tuning and not start pulling shots or anything until it has finished.


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## mrmike1

Today had coffee, very tasty, and now, again EEEE. Something is wrong with the sensor. I have a spare rtd probe from when I made my own sous vide and it works with the PID. I'll have to remove the boiler and make sure the sensor is ok. If not, I have to buy from Auberins. 25USD and shipping 40









Any ideas?


----------



## mrmike1

And another thing, the when I get the sensor to work, it says its 40c, and I the boiler was not turned on. The other sensor says its 25c.


----------



## marcuswar

How have you fitted the probe? Is it stuck to the outside of the boiler or screwed into the thermostats hole?


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## mrmike1

The sensor is in the thermostat hole. I've removed the entire boiler and checked for defects. No major defects. I plug into the PID and still EEEE. When I use my rtd sensor from the sous vide, it works. However, the working rtd is a prob and won't fit.

I will now try to see if the broken sensor will work with my other PID.

My question is, if I need a new rtd sensor, where can I buy one from the UK?


----------



## mrmike1

I think I got it to work. I had to strip the sensor leads a bit since they were 'crimped'. phew, close call. I must have bent the wires during the mod. That's why it worked when I moved the cables around.


----------



## froggystyle

Glad you sorted Mike, lots of work for it all go tits up now!


----------



## marcuswar

Glad you sorted it mike. You can pick the thermo sensors up cheaply on eBay if you ever need one, or I think you can just trim back the wires and resolder them together. I don't think there is a sensor as such , its just two wires each with different properties that are welded together.


----------



## mrmike1

I'm glad I had all your support and that sous vide PID w/ sensor so I could trouble shoot. I'm going to do the OPV and finish modding this one. I was originally going to buy a db or hx, but cash is tight for a bit so thought I could have some fun and extend my machine. I've learnt a lot about the machine and it was a good experience.

The sensor was a big set back. I must have crimped it during the mod... what a nightmare. Now back to testing and making sure there is no water leaks.

Many thanks for all the support


----------



## mrmike1

Very good coffee today. Much smoother. Cant wait until the OPV mod. Still waiting for the 6mm silicone tube to come.


----------



## marcuswar

When I did the opv adjustment on mine it made the coffee taste smoother so you're going to have a VERY smooooooth coffee after doing it


----------



## mrmike1

I have two OPV's now. I did the original a while ago and now with this mod, added a second (primary) OPV between the pump and before the passive heat coil. So now, all the water that is dumped by the OPV is cold water. I had to readjust the original OPV to open above the new OPV and the new OPV is set to 9ish.


----------



## mrmike1

The new OPV fits in a per-existing hole in the case. Cool huh!


----------



## marcuswar

Excellent work Mike. Maybe you should post a definitive list of all the parts you used, there specification and where you purchased them from. It would make a great future reference for anyone wanting to do the same in the future.


----------



## mrmike1

As you can see, this is a much higher quality OPV than the stock. I had to use teflon tape at the BSP junction.


----------



## mrmike1

marcuswar said:


> Excellent work Mike. Maybe you should post a definitive list of all the parts you used, there specification and where you purchased them from. It would make a great future reference for anyone wanting to do the same in the future.


I'm happy to do that. Maybe it can be an article or sticky


----------



## mrmike1

As you can see, the new OPV in action! I'm glad I did this mod as the new OPV stiffens the pre-heat coil and the noise isn't as bad when starting the pump.


----------



## marcuswar

Sounds good to me although I'm not sure on the forum rules for this. Probably best to pm Glenn and ask him.


----------



## mrmike1

I wanted to thank Frank, Marcus, Kyle, Neill, froggystyle, and coffeeforums.co.uk for the guidance and inspiration to do this mod. I don't think I could have done this with out you guys!


----------



## Neill

It's been great reading this thread. Beyond anything I'd fancy trying but it looks great and I'm sure adds a lot more thermal stability. Thanks for posting it all.


----------



## mrmike1

I just drew a double shot's worth of water. No change to temp at all until the very end. As I turned the pump off, the temp dropped further for a second but quickly rebounded. Took about a minute to go back up to temp. I think with a puck, which should slow down the water input to the boiler, will offer even greater stability.

My theory why the massive drop of temp at the very end is that the cold water cools the copper tubing quickly and this cools down the boiler. I think about 20-30ml fit in the copper tubing.


----------



## mrmike1

Neill said:


> It's been great reading this thread. Beyond anything I'd fancy trying but it looks great and I'm sure adds a lot more thermal stability. Thanks for posting it all.


I know the feeling, but I like a challenge. I'm a layman when it comes to plumbing


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## marcuswar

Thanks for compliment mike but all kudos must go to you, we've only talked the talk whereas you've walked the walk


----------



## mrmike1

mrmike1 said:


> I just drew a double shot's worth of water. No change to temp at all until the very end. As I turned the pump off, the temp dropped further for a second but quickly rebounded. Took about a minute to go back up to temp. I think with a puck, which should slow down the water input to the boiler, will offer even greater stability.
> 
> My theory why the massive drop of temp at the very end is that the cold water cools the copper tubing quickly and this cools down the boiler. I think about 20-30ml fit in the copper tubing.


Or at the end of the shot, finally, cold water enters the boiler and causes a quick drop in the temp. This is more plausible, me thinks.


----------



## mrmike1

I pulled a few shots. 2C drop in temp during the entire shot. I'm not sure what the temp at the group head is doing. I lowered the set point to 100 to compensate for the pre heat mod. The shot is very clean and smooth, but maybe a little thin? I'm not sure if that I just got used to bitter/ sour shots from before the mod or if something is wrong. Pressure at grouphead is a little over 9bar with a very small of water throughput. Do you think I should raise it?


----------



## Kyle548

mrmike1 said:


> I pulled a few shots. 2C drop in temp during the entire shot. I'm not sure what the temp at the group head is doing. I lowered the set point to 100 to compensate for the pre heat mod. The shot is very clean and smooth, but maybe a little thin? I'm not sure if that I just got used to bitter/ sour shots from before the mod or if something is wrong. Pressure at grouphead is a little over 9bar with a very small of water throughput. Do you think I should raise it?


Leave it where it is for now.

Are you getting 9 bar static?

You need 10 bar static - that's 10 bar measured with a PF locked in and a pressure gauge.

When beans in, the pressure will be lower, as water is able to seep though the grounds and drop the pressure a little - apparently this works out at about 1 bar when you have such big pressures.

What beans are you using and what's your input/output and timings?

I'd be interested in seeing this in action actually and of course, your welcome to come and try some shots pulled on my HX for comparison.

I wonder when your going to do the scales mod froggy style did...


----------



## mrmike1

Its about 9.5, but not static as some water is leaking through.

Kyle, you should come over sometime and try some shots yourself and tell me what you think. PM me


----------



## Kyle548

mrmike1 said:


> Its about 9.5, but not static as some water is leaking through.
> 
> Kyle, you should come over sometime and try some shots yourself and tell me what you think. PM me


Up the pressure a little bit.


----------



## mrmike1

Just did. Had to take the entire OPV out since the adjustment is on the bottom and couldn't access it. A few turns and perfect 10bar. Not too hard. Now I have to check for leaks again. I'll let you guys know if the coffee tastes 'fuller' tomorrow.

Btw, I'm using Fudge from Rave. I'll have to pull out the scale for exact input/ output, but reckon its about 17g coffee in under 30 seconds.


----------



## mrmike1

Today's coffee was good. Nice texture, full tasting. I think the OPV 10bar did the trick. I did 17g in 29 sec (8 sec infusion) and ended up with 39g of espresso using a 17g LM basket. Steamed some milk with it, very smooth.


----------



## froggystyle

Great news Mike, next mod then... ?


----------



## mrmike1

Maybe insulate boiler


----------



## JK009

mrmike1 said:


> Today's coffee was good. Nice texture, full tasting. I think the OPV 10bar did the trick. I did 17g in 29 sec (8 sec infusion) and ended up with 39g of espresso using a 17g LM basket. Steamed some milk with it, very smooth.


Well done. Congratulation!

When you finish everything, I was wondering if you can let me to borrow the Pressure gauge kits for OPV mod. I will be very glad if you agree. Please PM me for the delivery fee and address. Thank you in advance

Vo


----------



## froggystyle

Fit a fixed pressure gauge mike..


----------



## marcuswar

Vo

There are a few people offering to lend out a pressure gauges over on the "pay it forward" thread ;

http://coffeeforums.co.uk/showthread.php?16407-Pressure-gauge-opv-for-Classic

http://coffeeforums.co.uk/showthread.php?15051-Gaggia-classic-gauge-and-adapter

http://coffeeforums.co.uk/showthread.php?14111-Gaggia-classic-pressure-gauge-pass-around-(pf-not-included)

You could even just make your own. The gauges are only about £6 - 8 on eBay.

If you have a bottomless portafilter you could follow my guide to making one, I have a spare set of dowty washers and a nut that I can send you (free of charge) so you'd only need the gauge and a single basket. The nice thing about using a bottomless portafilter is that it doesn't involve removing the spout from your existing portafilter and its simple and quick to install/de-install.. just click and go.

http://coffeeforums.co.uk/showthread.php?17102-Making-a-pressure-test-gauge-using-a-single-basket


----------



## mrmike1

Hi Vo

I'm still using try to find the best setting. However have you tried the "pay it forward" section?


----------



## mrmike1

I was thinking about it. But I'm not sure how to bore the hole in the case and what kind of connection the gauge and current system would need. I'd need to bore a 55mm hole into metal.


----------



## mrmike1

As Frank rightly said, a gauge on the front will only show the pressure at which the OPV is set. I'll pass on this mod. Still might do the insulation mod.


----------



## nitrex

might be worth seeing if you can source some copper piping that they use for air conditioning systems. It comes rolled up and is easy to bend without the need of a pipe bender, but, as for the fittings I'm not 100% sure if you'll need to use air conditioning equipment or plain old plumbers fittings.


----------



## marcuswar

Isn't that just microbore I.e. 10mm pipe. Its used a lot on new heating systems as its easier to route around and hide in walls etc. Personally I don't like it used in heating systems as the pipe is too easily damaged and bent if hit by a vaccum cleaner etc.


----------



## mrmike1

It has been a few weeks since I finished the preheat mod. No leaks! I'm happy with the mod. I get maybe 1 or 2 degrees difference at the PID during the shot. Taste has improved greatly. The only issue I have is I must have damaged the RTD sensor. I think I crimped the wire somewhere. I occasionally get a PID sensor error. A replacement from Auberins will cost close to 30GBP and I don't want to spend that kind of money.

I know the sensor wire is insulated in teflon. Can I cut the wire near the sensor head and replace it with a wire of my choice? If I can't use regular copper wire, perhaps I can sacrifice another Pt100's wire and slice it in?

Once the sensor is sorted, the last bit is to calibrate the grouphead temp. Any ideas?


----------



## mrmike1

http://www.thermosensedirect.com/acatalog/tw_welded_tip_fast_response_thermocouple_sensor.html

Or I can buy this one and solder it onto the M4 bolt? Or install it somewhere even better.


----------



## marcuswar

I may be wrong but I didn't think there was a sensor as such, its just two wires of differing composition that are welded together at the end. Presumably the amount of resistance is then proportional to the amount of heat. I believe you should be able to cut the wire and just solder together (welding is better but solder should work OK) to form a new "sensor".


----------



## mrmike1

So are the two wires different material, or is it just the tip? If it is just the tip, than I can replace the wire.


----------



## marcuswar

Oops. just realised you are talking about a PT100 sensor. I was talking about a K series theromocouple which is what I used when I modded my Gaggia Classic with a PID. I think you are correct that a PT100 does have a sensor at the end unlike the thermocouple. Sorry for the confusion.


----------



## marcuswar

mrmike1 said:


> So are the two wires different material, or is it just the tip? If it is just the tip, than I can replace the wire.


Moot point but yes, I think both wires are different materials for their whole length rather than just the tip. I'm no expert in this but that is my current understanding. certainly one online blog I read described how he cut the "sensor" end (actually just a protective cover) off the probe, drilled a bolt and thread the wire through and then soldered to the ends together and inserted the bolt into the base of the Classic boiler instead of the original thermostat.


----------



## mrmike1

Do you have a link to the blog?


----------



## mrmike1

Tomorrow I'll try to add some wire leads. If it works, I'll replace the entire wire, hopefully it will work.


----------



## mrmike1

Any recommendations to calibrate PID temp at the group head without buying a Scace? Tasting the coffee puts me at 102, but I'm not confident enough to say my palate is good enough.


----------



## Charliej

Keep turning it up until the water coming out of the group flashes to steam you then have boiling point for your altitude above sea level, which gives you a reference you can say is 100 degrees c for easy working out.


----------



## mrmike1

Great idea, so the idea is increase to flash point than subtract 7 to get 93?


----------



## mrmike1

I got it to flash at about 111/ 112. So minus 7 would put it at 104, 105. I always wondered as boiling temperature changes with altitude, is the 93C relative to boiling or absolute to 93C?

Just got back from dinner and the sensor is saying EEEE again. grrrrr. I'll have to play with it tomorrow.


----------



## marcuswar

mrmike1 said:


> Do you have a link to the blog?


Sorry Mike, I've looked through my browsers bookmarks but can't seem to find it. I *think* it may have been this link ;

http://www.thedomesticbarista.com/index.php/Adding_a_PID_to_a_Gaggia_Coffee_espresso_machine.

but the server seems to have gone awol...

If I do manage to track it down I'll post it on here.


----------



## mrmike1

Oh no problem about the blog.

I think I fixed it by removing the crimped wire.









If you look closely towards the end of the right side, you can see where I crimped it by accident when I was doing the mod. Now I just have to rewire everything. I just hope the leads are long enough.


----------



## mrmike1

So I still was getting an EEEE code. We decided to take the boiler out but forgot to unclip the sensor from the PID and one of the wires ripped out from the sensor end. It's bad news







I just bought a new sensor from Auberins. Hopefully it doesn't take too long to arrive and I hope that it will fix the problem.

For now, we will use the Aeropress.


----------



## froggystyle

Nightmare Mike!

Fingers crossed when you get the new sensor it will back to normal.


----------



## mrmike1

Thanks for all the support. It was a rough morning, I'm glad my wife was there to support me. I have to say, the aeropress isn't that bad.

Any of you guys going for the Manchester crawl this Saturday?


----------



## mrmike1

The sensor came today! Plugged it in and it works. Now to recalibrate everything. Made a latte at 102 and it was bitter. Will try 100 later. One thing I noticed wit the old sensor is that it gave a higher reading than it was supposed to. The new one calibrates well with my cooking sensor (at room temp on start up). What a journey!


----------



## seeq

Might be me.... But water becomes steam at 100c so anything over 99 seems pointless for brewing?


----------



## Charliej

seeq said:


> Might be me.... But water becomes steam at 100c so anything over 99 seems pointless for brewing?


The higher temperature is including an offset so you get the desired temperature at the group.


----------



## seeq

Thinking about it, I'm just being stupid. Under pressure the boiling point of water would be greater anyway and it's going to cool coming through the group..... Forget I spoke


----------



## mrmike1

I could calibrate the offset so the PID would show what is happening at the grouphead vs the boiler, but I don't have a sensor portafilter to do the job. The PID originally came at 102 (if I remember) as Auberins said this would give you 93 at the grouphead. However with the preheat mod, change in water temperature isn't as drastic.

I'll report tomorrow.


----------



## mrmike1

Today, I tried 100C and coffee was still bitter. I tried calibrating by finding the flash boil point and subtracting 7. It was flash boiling at 103-104, so I tried 96C and the coffee wasn't bitter at all. Still need to tweak. It is very interesting that the old sensor gave me a flash boil at a much higher temperature. Lesson learnt, new sensor, new calibration.


----------



## mrmike1

Its been over a month and still works well. I think its safe to say... success!


----------



## rontheotherhand

Hello,

I spent a lot of time reading over the various forum on how to tackle this mod. I've attempted most of the Mods available to the Gagga Classic ( PID, brass plate shower screen,IMS baskets etc) with varying degrees of success however I found the results a bit underwhelming when compared to the amount of time / money put in vs the other two machines i've had over the past 12 months as stock ( Delonghi Dedica and Sage Duo Tempo).

I've lost count of the amount of money i've spaffed against the wall on mods in the pursuit of better coffee.

Installing a PID was supposed to be a game changer but I still found most of my shots sour and couldn't get my head around it. Using the WDT technique made a difference, as did using a hammer tamper but still sub optimal.

After reading a bit more on temp stability and intrashot temps / i put my problems down to the small boiler and the fact that cold water is being fed into the boiler as each shot is drawn. Or at least, that's how i understand it.

Anyway, suffice it to say - thanks mainly to this thread, I attempted this mod and am pleased with the results. I just thought i'd add my two cents to anyone else who's attempting to try this...



You 100% need a second OPV ( appreciate this is touched on in this thread) but it's pointless tackling this mod without one. As others have mentioned, the hot water in the copper pipe will just flush back into the tank. I tried it with the original and got a 4 deg drop or more evetime.


I found having two OPVs in the machine too hard to adjust. Easiest way to get around this is cap off the original one that is connected to the boiler.


Remove the spring, get a bit of copper pipe, put it where the spring was and then put everything back on.


My machine is I a pre 2010 model with only a hole for the water inlet so you'll need to drill a small hole for the OPV water to exit on the platform inside the case where the pump sits.


Bending the copper pipe around the boiler is a no. Instead, i used a small glass tumbler and made a coil first. I had to move the solenoid valve 90 degrees to accommodate it which then made me wonder if i should have used smaller pipe. So far no problems but time will tell.


If i was attempting this again, I would probably use 6mm copper pipe instead of 8mm but that's all they had in B&Q. As the pipe is 8mm i have a big hole where the gauge used to be which I'm still trying to get my head around sorting


M10 x 1.00 is the only tap that will work. I tried with the kit I got from amazon with a m10 x 1.25 and 1.50 but no luck. Don't attempt to thread the compression fittings with anything else.


Thats about it, I think. My temps drop about 2 degrees over a 35 sec pull but pretty much stay there -the most important bit, the coffee taste much better.

Happy to answer any questions for people attempting this mod. It wasn't a 5 minute job - it took me about 2 weeks in all as i had to get parts from various places but give yourself a good day to do it.

last but not lest - I have electrocuted myself ( at least) three times on this machine, so be careful.

https://ibb.co/PGWS5mJ

https://ibb.co/xC2Z99W


----------



## minerek

@rontheotherhand how i can contact with you? i need support with this


----------



## phario

rontheotherhand said:


> Hello,
> 
> I spent a lot of time reading over the various forum on how to tackle this mod. I've attempted most of the Mods available to the Gagga Classic ( PID, brass plate shower screen,IMS baskets etc) with varying degrees of success however I found the results a bit underwhelming when compared to the amount of time / money put in vs the other two machines i've had over the past 12 months as stock ( Delonghi Dedica and Sage Duo Tempo).
> 
> I've lost count of the amount of money i've spaffed against the wall on mods in the pursuit of better coffee.
> 
> Installing a PID was supposed to be a game changer but I still found most of my shots sour and couldn't get my head around it. Using the WDT technique made a difference, as did using a hammer tamper but still sub optimal.
> 
> After reading a bit more on temp stability and intrashot temps / i put my problems down to the small boiler and the fact that cold water is being fed into the boiler as each shot is drawn. Or at least, that's how i understand it.
> 
> Anyway, suffice it to say - thanks mainly to this thread, I attempted this mod and am pleased with the results. I just thought i'd add my two cents to anyone else who's attempting to try this...
> 
> 
> 
> You 100% need a second OPV ( appreciate this is touched on in this thread) but it's pointless tackling this mod without one. As others have mentioned, the hot water in the copper pipe will just flush back into the tank. I tried it with the original and got a 4 deg drop or more evetime.
> 
> 
> I found having two OPVs in the machine too hard to adjust. Easiest way to get around this is cap off the original one that is connected to the boiler.
> 
> 
> Remove the spring, get a bit of copper pipe, put it where the spring was and then put everything back on.
> 
> 
> My machine is I a pre 2010 model with only a hole for the water inlet so you'll need to drill a small hole for the OPV water to exit on the platform inside the case where the pump sits.
> 
> 
> Bending the copper pipe around the boiler is a no. Instead, i used a small glass tumbler and made a coil first. I had to move the solenoid valve 90 degrees to accommodate it which then made me wonder if i should have used smaller pipe. So far no problems but time will tell.
> 
> 
> If i was attempting this again, I would probably use 6mm copper pipe instead of 8mm but that's all they had in B&Q. As the pipe is 8mm i have a big hole where the gauge used to be which I'm still trying to get my head around sorting
> 
> 
> M10 x 1.00 is the only tap that will work. I tried with the kit I got from amazon with a m10 x 1.25 and 1.50 but no luck. Don't attempt to thread the compression fittings with anything else.
> 
> 
> Thats about it, I think. My temps drop about 2 degrees over a 35 sec pull but pretty much stay there -the most important bit, the coffee taste much better.
> 
> Happy to answer any questions for people attempting this mod. It wasn't a 5 minute job - it took me about 2 weeks in all as i had to get parts from various places but give yourself a good day to do it.
> 
> last but not lest - I have electrocuted myself ( at least) three times on this machine, so be careful.
> 
> https://ibb.co/PGWS5mJ
> 
> https://ibb.co/xC2Z99W


 Love this update. Thank you.

I've seen the pre-heater coil mod for a few different cases now---it's quite challenging in the Gaggia.

The other way to do it is to fashion a pre-heater box, and this is something seen around these parts:

https://www.coffeeforums.co.uk/topic/30868-gaggia-classic-preheater-box/?do=embed


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## rontheotherhand

That's a cool mod. Interesting the guy mentions zero drop during intrashot temp ... I'm envious now and am thinking how he managed it. I guess with the water being in all one place it doesn't lose any of its heat like with the copper pipes.

Maybe I need to insulate the boiler?

I did think of doing a box mod but the only post I could find the chap mentioned milling his own box. I wanted something off the shelf. The other option was adding a thermobloc but I didn't really fancy that either.


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## Zatogato

rontheotherhand said:


> Hello,
> 
> I spent a lot of time reading over the various forum on how to tackle this mod...


 Wow what an effort! I'm also exploring all the possible mods for the GC at the moment and this is very impressive. This seems like the most difficult/technically challenging of all of them so I'll wait until my other experiments are all finished before considering it.


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