# OPV mod done!



## froggystyle (Oct 30, 2013)

Burnt my fingers countless times!

Swore at the bolt on top as it was stiff as Jesus!

My thumb hurts as my adjustable is tighter to open than my wifes purse!

But all done, dropped to 9 bar.

Also chucked in a temp probe on top of the boiler with a reader on top of the gaggia to monitor temps.

Now i have to wait for it to warm up so i can get drinking.


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## El carajillo (Mar 16, 2013)

Where is the photo ??? come on keep up!!!


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## froggystyle (Oct 30, 2013)

Nothing exciting to show really, just fitted one of these, fixed it to the top of the boiler and stuck the reader to the wall above the gaggia.

http://www.ebay.co.uk/itm/360752345213

I know the temp will not be perfect reading but just wanted to see what it does though out the whole process, i may fix it inside the gaggia case at some point..


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## El carajillo (Mar 16, 2013)

I thought you had drilled and tapped it into the boiler !!. I presume it clips /clamps onto the outside same as thermal fuse .


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## froggystyle (Oct 30, 2013)

lol now way!

Not brave enough for that.


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## marcuswar (Aug 19, 2013)

When I was experimenting with a PID on my old Classic I just stuck the thermocouple onto the boiler on with bluetack. It seemed to work fine and I didn't have any issues with it falling off in the few weeks I had it on. I've also read of people using SUGRU which is probably a better (more semi permanent) solution.

How have you found your coffee since doing the OPV mod froggy ? I'm sure when I did mine I found the flavour improved and was smoother and more well rounded... but was it emperors new clothes ?


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## froggystyle (Oct 30, 2013)

Yep bluetack used here also, will have a look around for something a bit more permanent tomorrow.

Only pulled one shot off as i would like to sleep tonight, seemed better, but to be honest (And please dont shoot me down) im using lavazza at the minute so its hard to tell, really screwed up my bean order last month so ran out last week, have roasted some MM but need to wait, plus the fudge and italian job i got from rave need to rest also.


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## Kyle548 (Jan 24, 2013)

You want to set your OPV to 10, ideally.

Apparently.

The guys at coffee geek seem to suggest 10 static is the way to go for 9 when pulling a shot.


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## froggystyle (Oct 30, 2013)

i did a google and found most of the videos/answers were coming back with 9..

Will give it a try again in the morning and if i dont feel its right i can easily up it to 10.


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## marcuswar (Aug 19, 2013)

Kyle548 said:


> You want to set your OPV to 10, ideally.
> 
> Apparently.
> 
> The guys at coffee geek seem to suggest 10 static is the way to go for 9 when pulling a shot.


I think that's correct and the advice is that you set to a 10 if you are reading the static pressure i.e. with a pressure gauge on the portafilter. The reason being that when you pull a real shot you will loose a bar of pressure as the water passes through the coffee puck.


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## froggystyle (Oct 30, 2013)

I need to open it back up soon anyway to fit the temp reader thing better, so will notch it back up too 10.

Cheers for the advise fellas.


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## marcuswar (Aug 19, 2013)

froggystyle said:


> I need to open it back up soon anyway to fit the temp reader thing better, so will notch it back up too 10.
> 
> Cheers for the advise fellas.


I'd give SUGRU a go for fixing it onto the boiler. I believe B&Q are supposed to stock but if not you can by it direct from SUGRU or from sellers on eBay.


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## Kyle548 (Jan 24, 2013)

Probably best to fix to the top of the boiler.

Cold water comes in the bottom and the exit for the group is at the top of the boiler.

Basically takes advantage of thermal density changes to make the most out of the small boiler.

The tstat is at the bottom of the boiler so it can react to temp changes from cold water coming in more quickly - if your simply measuring the temp of the boiler for when to pull a shot, then probably the top, where the hottest water is, would be best.


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## m4lcs67 (Mar 16, 2014)

Good call matey,

I had also read that setting it to 10 static gives you 9 dynamic and that is what I set mine to a couple of weeks ago. It was set to 12 bar from the factory and I had read from many quarters that you should turn it anti-clockwise 270 degrees (three quarters) and I originally did that, but it was miles out, so with a bit of faffing I managed to get it set at 10 bar. Took me about 5 goes. Not that difficult really. I like the idea of the temp gauge. Thanks for posting the link to it.


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## froggystyle (Oct 30, 2013)

El carajillo said:


> I thought you had drilled and tapped it into the boiler !!. I presume it clips /clamps onto the outside same as thermal fuse .


Has anyone ever done this on the forum, pics?

WOuld be interested to see how easy it is.

This morning whilst brewing, i noted the temp shot up over 100 c causing the display to error out due to its limit, just wonder what the water it actually reaching inside the boiler!


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## marcuswar (Aug 19, 2013)

Personally I would do the opposite and just use a bolt of the correct size and thread pitch to fit the existing temperature stat, drill a hole through it down the shaft and then wire the sensor to the end. I would be very wary of modifying the actual boiler as once its done, you can't undo it.

If you've got the sensor at the top of the boiler then this is hotter than the bottom where the cold water comes in when the pump runs. As soon as you "brew" you're forcing cold water into the boiler so the actual temperature of the water coming out the head will vary considerably and you are relying on an average temperature over the whole pull. This is one of the reasons why people temperature surf on the Classic, trying to start the shot at an exact same point in the temperature cycle each time to obtain a consistent average. With you're temperature probe being stuck on the outside of the boiler you are measuring the temperature of the boiler metal work not the water inside which will be at a lower temperature due to thermal lag etc. I don't think you should take the readings as absolute temperature values and they should be used more as comparative values between shots.


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## froggystyle (Oct 30, 2013)

Yeah not that keen on drilling holes really, i might just leave it on top but fix it better.

Have noted some better ones on Ebay, that go upto 120 as mine only goes up to about 105 i think.

Plus they look better!

http://www.ebay.co.uk/itm/151185286637?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_426wt_1141

Also my little mind is thinking about some scales with a seperate display to fit along side the temp one in the case.


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## marcuswar (Aug 19, 2013)

They look very nice.. only issue I can see is that they need a 12v DC supply, meaning you'll need some form of transformer to run them (or batteries!). A set that ran off 240v would make them a lot easier to wire into the machine.

I've often thought there should be a way of integrating a set of scales into the drip tray of an espresso machine so you could monitor your extractions easily, especially if the display was zero'd by the activating of the brew switch.


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## froggystyle (Oct 30, 2013)

I was thinking of adding some LED 12v lights under the body to light up the tray when the power is turned on, found this to sort that so can drop the temp dial into it.

http://www.ebay.co.uk/itm/290883688146?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

http://www.ebay.co.uk/itm/110605219907?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

I have been looking at scales this morning, i may take my little scales apart later and see if the wires between the plate and main board can be increased in length, if so then i may look at trying to build into the drip tray in some way with the display built into the case of the gaggia, it should be simple to do...


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## Mrboots2u (May 10, 2013)

Kyle did something similar to his classic , he may be able to suggest or help also.


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## froggystyle (Oct 30, 2013)

Something else i thought of last night, having a permanent pressure gauge in the machine, but at what point of the pipework would you plumb this in?


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## Kyle548 (Jan 24, 2013)

froggystyle said:


> Something else i thought of last night, having a permanent pressure gauge in the machine, but at what point of the pipework would you plumb this in?


Between the pump and the OPV.

But its too hard to plumb it in, the line pressure is so high that the joints will just leak no matter what.

I found it too hard to make it leak proof and abandoned the project.


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## froggystyle (Oct 30, 2013)

Kyle548 said:


> Between the pump and the OPV.
> 
> But its too hard to plumb it in, the line pressure is so high that the joints will just leak no matter what.
> 
> I found it too hard to make it leak proof and abandoned the project.


Cheers, shall think no more on that one!


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## m4lcs67 (Mar 16, 2014)

Pimp my Gaggia, eh?????


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## froggystyle (Oct 30, 2013)

Oh yes Malc, got loads of ideas in my head....


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## marcuswar (Aug 19, 2013)

I think the best mod , and the one I was going to do myself before I ended up upgrading instead, is to wrap a coil of copper pipe around the boiler to preheat the incoming water and improve temperature stability while pulling a shot.


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## urbanbumpkin (Jan 30, 2013)

marcuswar said:


> I think the best mod , and the one I was going to do myself before I ended up upgrading instead, is to wrap a coil of copper pipe around the boiler to preheat the incoming water and improve temperature stability while pulling a shot.


Have you guide to this?


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## froggystyle (Oct 30, 2013)

Yes, spotted that on a site today, looks a good mod.


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## froggystyle (Oct 30, 2013)

urbanbumpkin said:


> Have you guide to this?


http://www.gaggiausersgroup.com/index.php?topic=338.0


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## Kyle548 (Jan 24, 2013)

It's hard though.

I tried it and found it hard to seal or bend the pipe without kinking it.

I did it at the same time as I tried the manometer, so the added complexity of a t joint probably didn't help things though.


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## marcuswar (Aug 19, 2013)

What size pipe did you use kyle, standard 15mm or 10mm microbore? I would think filling the pipe with sand while you bend it would stop any kinking issues.


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## Kyle548 (Jan 24, 2013)

marcuswar said:


> What size pipe did you use kyle, standard 15mm or 10mm microbore? I would think filling the pipe with sand while you bend it would stop any kinking issues.


Microbore.

It's just that the boiler inlet was so close to the classic case that it was really hard to bend the pipe sharply enough.

You need a hairpin bend, almost.


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## marcuswar (Aug 19, 2013)

If it needed such a tight bend why not just solder in an elbow joint rather than trying to bend it ?


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## Kyle548 (Jan 24, 2013)

marcuswar said:


> If it needed such a tight bend why not just solder in an elbow joint rather than trying to bend it ?


It's very hard to find fittings for micro bore piping.


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## El carajillo (Mar 16, 2013)

Kyle548 said:


> It's very hard to find fittings for micro bore piping.


Have you tried heating& plumbing supplies ? Also caravan sales use small bore for gas. Also hydraulic and pneumatic components.


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## Kyle548 (Jan 24, 2013)

El carajillo said:


> Have you tried heating& plumbing supplies ? Also caravan sales use small bore for gas. Also hydraulic and pneumatic components.


Components need to be capable of handling upto 15 bar.

Anyway, I already upgraded to something new.


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## froggystyle (Oct 30, 2013)

Kyle548 said:


> Between the pump and the OPV.
> 
> But its too hard to plumb it in, the line pressure is so high that the joints will just leak no matter what.
> 
> I found it too hard to make it leak proof and abandoned the project.


What material pipe did you use?


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## Kyle548 (Jan 24, 2013)

froggystyle said:


> What material pipe did you use?


Copper microbore.


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