# Gaggia OWC restoration



## Norvin (Sep 10, 2014)

I thought that I would share my experiences renovating anexample of the model commonly known as the Gaggia OWC (Old White Coffee). Except that this example isn't white, it's afetching 80's sludge brown colour, it is not the common Coffee model, but it iscertainly old. I got it from eBay for £10 reasoning that it would be worth itfor entertainment value alone, and it was located only seven miles from me sowhy not?The person that I bought itfrom told me that he had paid £300 for it in 1983 (equivalent to about £950nowadays). He also told me that it works fine except that it doesn't steam.Yeah, well, we'll see about that.









There's not much information on this model out there, but itis generally regarded as the precursor to the Classic model. After havingstripped it and fiddled with it for a few weeks I agree with some opinions thatit can be regarded as almost a Classic on steroids. It has a powerful pump,1500W heating element, OPV, large three way solenoid valve and a large boilerwith a substantial brass group casting. Downside is lack of spares. There is ageneral feeling of quality and solidity to it. Not that it's perfect, there area few design deficiencies that I hope to address as I work on it.

The serial number is 3101, possibly making it a very earlymodel.









The brass group casting is slightly different from other pictures of OWCgroups posted online, suggesting that it is an even earlier casting pattern: itdoesn't have a raised boss where the OPV mounts and has an unused, drilled andthreaded boss behind the OPV for mounting a thermostat.









The boiler is larger than the later Classic type. See the photoshowing the two side by side to see how much bigger it is. OWC on the left, later boiler on the right.









I'll post further details later.


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## Norvin (Sep 10, 2014)

Okay, so here we go.

When I got it home I put water in the tank and switched iton. The pump made a laboured, hammering sound, but no water came out anywhere.The boiler started to warm up so at least the heating element was working. Imade a note of the connections and started the dismantling.

All of the screws holding the assembly together were seizedin place with corrosion. Two of the screws loosened with a snap, one strippedthe internal hexagon, the fourth was a cheese headed set screw. I cut a slot inthe head of the stripped Allen screw and got this and the other screw loosewith an impact driver.






Phew, one problem solved, it's not unusual to shear thehead off these screws when they are this tight.

This is what I found-









Just a little bit of scale. The boiler seal haddisintegrated, there was staining on the outside of the boiler to indicate longterm extensive leakage. The inlet and steam elbows were completely choked withscale. The mating face of the aluminium boiler had corroded badly. Luckily, thegroup gasket was in reasonable condition and still soft, a good thing as theyare almost impossible to source. OPVvalve was choked with scale.









Everything was given a good soaking in citric acid solutionand cleaned up. The scale in the steam elbow had to be drilled out as thedescaling solution just wouldn't penetrate, luckily there didn't seem to be anyscale in the steam valve. The pump wouldn't pump, even after tying to prime byinjecting water into the inlet with a syringe, so it was dismantled andcomponents soaked in descaling solution. After reassembly and priming, the pump worked, one job done.


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## hotmetal (Oct 31, 2013)

Blimey! That's scale on a grand, er, scale! Drilling out the steam pipe - wow. I admire your determination - sounds like it will be a good machine if you can actually get all the scale out and replace all the seals. Keep those updates coming!


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## Norvin (Sep 10, 2014)

It was the steam elbow that was drilled out (actually, both elbows were choked), everything downstream from that was scale free.

I'll post the next installment later.


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## Norvin (Sep 10, 2014)

The Boiler.

It has both thermostats are mounted on the top surface. There isa boss on the side of the boiler which looks to be a better placement for thebrew thermostat, but there is no room to mount one as the OPV valve body is inthe way. The boss is threaded with a standard M4 thread so I intend to use thisposition to mount a thermocouple here on assembly to give a future option toput a PID on the machine.

One design flaw here is that fresh water is pumpeddirectly into the boiler chamber, cooling the hot water in the boiler. Excesspressure is vented out of the OPV by venting hot water back to the tank. Somepeople get around this drilling and tapping a new connection for the inlet elbow on the side of theOPV mounting boss, that way pressure is regulated by venting cold water beforeit reaches the boiler. This casting doesn't have the OPV mounting boss, so Imade a stainless steel bridging tube to take water to the OPV directly from theinlet.

Three small holes drilled in the tube allow some water into the boiler.









The corrosion in the aluminium boiler mating surface wasquite deep, so deep that facing the surface off in a lathe wasn't possible asit would leave the mounting flange too thin. I filled with the holes with epoxyputty and once set faced off the surface by rubbing it on a sheet of wet anddry emery paper on the sheet of plate glass to maintain flatness.









I bought a 86mm ODx 3mm viton O ring off eBay to act as aboiler gasket. I should have bought a 3.5 or possibly 4mm thickness as the Oring is barely compressed on assembly, made worse if any kind of siliconjointing compound is used on the joint. It remains to be seen if this O ring isadequate but so far the pressure has held.


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## Norvin (Sep 10, 2014)

OPV.

This was choked with scale. After soaking in descaling solution the scale went but the adjusting nut wouldn'tunscrew, not helped by the fact that it was made of brass and the two slots forthe adjusting tool will round off if too much pressure is used. I got itunscrewed by making a special tool in the lathe, see pictures.









Use the holes in the tool as a guide to drill two holesthrough the plug, then (purists look away now) turn the drills around andgently tap them into the new holes in the plug. The plug can then be unscrewedusing the tool. The thread in the OPV body is 3/8" bsp, (not the strange threadused on later OPV's), so I already had a suitable tap to run though the threadsto clean them up.

I decided to adjust the OPV while the boiler was out of thecase, so that any leaks could be quickly identified and dealt with withoutspraying water over the electrics.









My set up looks complicated but it meansthat I can use the steam outlet valve for the pressure take off point. One tapis used to damp down needle oscillations the other valve is there to let airout of the system. OPV was adjusted to 10 bar. There were some leaks from the boilerseal and solenoid mounting face (new seals should sort that out). I have flaredthe outlet on the bottom of the group head to reduce the speed of the jet ofwater from the pump, there is no dispersion block as on the later boilers, sothe jet of water punches a hole in the puck. I have reduced the speed of thejet by putting using two shower plates stacked, but some form of disc is neededto distribute the water more evenly over the shower plate. The group gasket was still soft. I turned itover to present a fresh flat face to the portafilter, this seems to work fine.


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## Norvin (Sep 10, 2014)

I've included a thermal cut off on top of the boiler for safety'ssake, there wasn't one on the machine originally. The neon light in the on offswitch isn't working but I don't think its worth opening out the switch to tryand fix it due to the possibility of breaking a working switch. The front amberlight is a boiler working indicator, not temperature ready indicator as on thelater Gaggias. The original portafilter that came with the machine is a flimsyaluminium affair I may cut the bottom off to make it bottomless where the lackof thermal capacity doesn't matter. Meanwhile, I use a spare brass portafilterfrom the later Gaggias.

So, after all that, what's it like? It makes reasonableespresso, just as good as a Classic.








There is lots of steaming capacity due tothe large boiler. If I wanted to improve it further, I would sort out adispersion disc and a PID, the thermocouple is already in place on the boiler. Itreally could do with repainting, the paint is tatty and I'm not a fan of thecolour, but due to its rarity I'm reluctant to change it.

Still, not bad for about £16 all in.


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## hotmetal (Oct 31, 2013)

£16 but a whole lot of effort! I'm seriously impressed, given that the limit of my techie ability is relubing the E61 group lever pins after back flushing!


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## ternary (Jan 12, 2020)

Any thoughts as to how you would go about adding a dispersion disc? I've been thinking of just drilling two more holes in my group casting, but I'm reluctant to do something so permanent. I'm running two shower screens for the time being, but I don't like seeing that divot in the puck.


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## Norvin (Sep 10, 2014)

ternary said:


> Any thoughts as to how you would go about adding a dispersion disc? I've been thinking of just drilling two more holes in my group casting, but I'm reluctant to do something so permanent. I'm running two shower screens for the time being, but I don't like seeing that divot in the puck.


 Interesting idea. Some machines (Rancilio Silvia, Fracino Piccino, Bezzera BZ02 and probably a lot more) have a brass dispersion disc held on by the central screw that also holds the shower screen. If one of those were used, there would be no need to drill any holes. The main problem is that the extra thickness would protrude into the portafilter basket. It may be possible to get around that by using a deeper basket with a bottomless portafilter.


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## Norvin (Sep 10, 2014)

People may be interested in an update on this machine as I have been doing a lot of work on it recently.

It all started when I thought that it may be a good idea to use a spare SSR relay to control the steaming with the PID. It took an age to get it working. The wiring on the OWC is different to the Classic so I had to go back to first principles to work out the various connections.









Then the problems started. While trying to work out the best setting for the steam temperature the water in the boiler started boiling violently; the extra pressure in the boiler had blown the main boiler seal. No water was seen inside the case but as the pressure in the boiler was now at atmospheric, raising the temperature in the boiler to 135c made it boil pretty violently. It was at about this time that the pump packed up...

Opening the boiler showed that the mixture of epoxy metal and slicone RTV that I had used to fill the deep pits in the boiler mating surface had degraded over time makng a mess inside the boiler. As this is such a rare machine in the UK and the boiler is unique to this model, getting a 240v replacement is very unlikely. So there was nothing for it but to machine the boiler face down to get a level sealing surface.









The four mounting lugs on the boiler are thinner now and not as strong, but time will tell if they are strong enough. I also took the opportunity to get a thicker boiler O ring as the old one was just barely protruding above the mating face when sitting in its groove. Further testing shows that there is a slight leak with the old, thinner seal, there are no leaks with the thicker seal. There are few details of these machines to be found and you can't order spares any more, so working on them has to involve an element of trial and error. I have an idea that the Silvia V1 boiler may be made to fit as the seals are a similar (slightly smaller) size, if anyone has an old one perhaps with a blown fused in element, I'd love to give it a try.


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## Norvin (Sep 10, 2014)

I moved the thermocouple mounting point from the base of the boiler to thermostat's original position on the top (same position as in the Ranclio silvia) as clearance with the OPV is very tight. I found that the old thermocouple mounting screw touched the brass OPV body which may have affected the heat readings by conducting the heat away. I've used a longer brass screw and a thick copper washer to get maximum heat transfer.









I fiddled with the old pump, I got it working but output was very poor. I had a more modern EX5 pump that was missing it's little ball valve, so I used the valve in the older pump to get it working. That is now in the machine, a shame as the old one was an all brass affair, no plastic bits in it. I replaced a faulty bulb in the main on/off switch.

There is a blanking screw with an 1/8 bsp thread underneath the group head that blocks off a connection between the three way valve and the boiler. This can be used to mount a gauge to adjust the OPV as shown here-









It is possible to permanently mount a gauge here, although it may get filled up with coffee waste. A better option may be to alter the boiler water feed and OPV connections, allowing a gauge to be mounted from the inside of the case. Perhaps a future project.


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## Norvin (Sep 10, 2014)

I wasted a lot of time trying to get the PID settings right, only to discover that the thermocouple was faulty, I must have pinched it a some point. Once replaced, setting up was much easier although the PID temperature reading is 21c higher than that measured by my thermometer. I have to use the offset just to get an accurate display.

It's all back together now, not everything may work as planned but it's all good fun. I'm experimenting with temperature settings at the moment.









I still think that this is a great machine, I think of it as the Classic's more brutal, burly, older brother. Everythings much more solid than the Classic. If you like fiddling with old machines then it is well worth seeking one out, although I have only ever seen one other for sale on ebay in the UK.


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## NitJay (May 18, 2020)

Great to read this, will be referring back to this thread as I got hold of a brown one of these for next to nothing recently. Will be a slow and long term project....


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## Norvin (Sep 10, 2014)

Was it you that bid over me recently, topped my massive bid of £15? If so, you massively overpaid, mine cost me about £8. Must be the Covid price hike that I keep reading about 😄


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## NitJay (May 18, 2020)

Haha I think it was! £16.

To be honest if you need any parts or anything in the future off it, let me know. I mostly bought it as I was curious.

I was going to start this weekend but suspect I will find some show-stopping horrors if you can't get parts.


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## Norvin (Sep 10, 2014)

NitJay said:


> Haha I think it was! £16.
> 
> To be honest if you need any parts or anything in the future off it, let me know. I mostly bought it as I was curious.
> 
> I was going to start this weekend but suspect I will find some show-stopping horrors if you can't get parts.


 I'll be very interested to see what it is like inside.


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## NitJay (May 18, 2020)

Funny you should say that I made this last weekend do document.


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## Norvin (Sep 10, 2014)

Looks like it is in better condition than mine was. Arrangement of OPV, boiler feed and brew thermostat has changed.

If I had known that it was in that condition I may have bid higher 😄.

Looks to be a nice project.


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## Smht85 (Nov 25, 2020)

I am also restoring a OWC, but I cannot find any details for the gaskets I need. So mostly boiler gasket and portafilter gasket (as these are thinner than the Classic gaskets). Do you maybe have this information for me?


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## Norvin (Sep 10, 2014)

I found that a 78.97 x 3.53 O ring works as a boiler gasket.

I made a group gasket from silicon sheet, no details recorded but I think that I gave some in a post on the now defunct Gaggia Users Group, which can still be found online.

@NitJay how are you getting on with your OWC?


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## supernova1477 (Jan 7, 2021)

I just purchased a used '83 Gaggia OWC from someone and the group head shower screen and shower holder were caked with old grounds and limescale. I bought a replacement shower head but I am still getting spraying water when brewing which causes some bad channeling. Does anyone happen to know how to remove the shower head holder/dispersion block? It seems stuck on there and there is only the screw hole in the center to grab onto. I would really appreciate any advice from anyone who has worked with one of these before.


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## supernova1477 (Jan 7, 2021)

So I was able to remove the ring that locks the portafilter to the boiler and successfully remove the gasket. It seems as though the dispersion block is built into the boiler itself, is this the case? If so I think I will try to find a way to makeshift some kind of dispersion plate to go between the block and shower screen in order to block off the ridiculous stream of water coming from the single dispersion hole. If anyone has suggestions I am all ears.


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## Norvin (Sep 10, 2014)

Yes, the 'dispersion block' is part of the casting.

You can help a bit by countersinking the exit hole to slow down the water.









I made a baffle plate to slow down and disperse the water, This was made from a face plate from a Miller ammeter (probably worth a bit now and I hate to think of the lead content of the brass) and a shim to create a little head space. Other people have cut up drinks cans etc. to make a similar. This seems to work well enough although I think that the shower holder from a Bezzera or Fracino (and others) with a deeper basket would be something worth looking at.


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## supernova1477 (Jan 7, 2021)

Thank you for your response, that was very helpful. I ended up using a soda can to cut a dispersion screen as a test and that worked much better. I will look into those face plates you recommended or something similar for a more permanent solution.


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## Norvin (Sep 10, 2014)

supernova1477 said:


> Thank you for your response, that was very helpful. I ended up using a soda can to cut a dispersion screen as a test and that worked much better. I will look into those face plates you recommended or something similar for a more permanent solution.


 I just used bits that were to hand and were the right size, you can probably get discs cut from cans to work pretty well, just keep the holes away from the same radius as the water exit hole. If you can get an arrangement of holes that work well could you post a picture of it here.


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## supernova1477 (Jan 7, 2021)

Of course! My first attempt has not been satisfactory, so I will continue to try different designs.

@Norvin I do have one question about countersinking the water dispersion hole, how did you manage to fit a drill in there? Or did you pull the whole boiler out?


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## supernova1477 (Jan 7, 2021)

I have been doing some reading on this water dispersion issue and came across this thread from a few years ago.

http://www.gaggiausersgroup.com/index.php?topic=1667.0

They came up with the idea of stacking the OEM shower screen and a third-party screen on the group head to dissipate the water stream. Since I ordered the IMS screen on Amazon and also cleaned up the original screen it came with, I decided to try this method out before attempting to drill into the bottom of the boiler, which makes me a bit nervous.

It is 8:30pm here and past my caffeination period for the day so I will try this in the morning and report back with results.


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## Norvin (Sep 10, 2014)

You will have to take the boiler out in order to get the clearance to drill.

I have just had a rummage in my junk box and came across this old screen,





















I can't remember what it is from but it will be either Bezzera BZ02, Rancilio Silvia or Fracino Piccino, perhaps someone with one of these machines could check for me?

It is an almost a perfect fit and can be used as is without any other modifications. I have pulled a test shot and can see only very small indents in the puck surface. I like it so much that I will leave that as the machine's screen.


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## supernova1477 (Jan 7, 2021)

Well I'm a bit late but I am having a lot of success with the double shower screen method. I stacked the OEM shower screen on top with the IMS screen as the outer most one and this seems to at least eliminate the stream of water. There is enough excess space in the shower screen cavity so that it almost lines up with the outer rim and retains a water tight seal.









So the pucks from the shots I have been pulling have been almost perfect! Seemingly no divots or any dispersion of the grounds. However, the water is not "raining" the way an espresso machine should, it is more like a deluge of water mostly coming from the center. This is better but I imagine I am getting an uneven extraction.








On another note, this may not be the appropriate place to has this out, but after backflushing and descaling my machine a few days ago, both the shower head and the steam wand have begun to leak water while the machine is heating up to brewing temperature. It is a bit strange since it is leaking in irregular spurts especially from the group. It's not a huge deal but if anyone knows what may be happening I would appreciate the input. I will attach a video of what is going on...


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## ting_tang (Jul 26, 2020)

I see water coming from the center just after the backflushing. In 1-2 days it starts raining.

I use the same scheme IMS over the standard, that's how it looks like.

I'm not sure but leaking during the heating could be sign of solenoid clogging, which is a reasonable, you descaled recently.


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## Norvin (Sep 10, 2014)

As @ting_tang suggests, the leaking is probably related to the descaling, leaks in the solenoid and steam wand suggests bits of scale are affecting the seals, it's easy enough to strip and clean the seals. Have you stripped and cleaned out the boiler yet?

That original aluminium portafilter is a bit flimsy, any of the later chromed brass portafilters will fit and are much nicer to use.


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## Norvin (Sep 10, 2014)

"However, the water is not "raining" the way an espresso machine should, it is more like a deluge of water mostly coming from the center. This is better but I imagine I am getting an uneven extraction."

I can't see how this could be significant. At 9 Bar/130 psi (or more if the OPV hasn't been adjusted) above and below the screen when pushing the water through the puck, any initial unevenness would quickly be evened out.


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## supernova1477 (Jan 7, 2021)

@ting_tang

Okay, I was thinking along those lines of a possible clog somewhere in the line as well. I bought the machine used and there was a ton of scale and oils under the OEM screen and on the boiler outlet behind it. And as a matter of fact the flow of the water returned to normal after a day or two like you said!

@Norvin

I have not opened up the boiler yet and I know I should sooner rather than later. I have heard stories of busted boiler o-rings and how hard they are to source so I didn't want to open up a can of worms. I guess it would probably best if I do so and make sure everything is up to snuff.

On the water dispersion I wasn't sure if being under pressure would negate the importance of that kind of flow, but thank you for clarifying that for me. I am new to all this so I really appreciate all the input!


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## Norvin (Sep 10, 2014)

supernova1477 said:


> @ting_tang
> 
> @Norvin
> 
> ...


 The boiler O ring isn't too hard to find, igave the dimensions in an earlier post. Just bear in mind when searching that it is an imperial size, not metric.

It's the group gasket that is hard to find but one can be made from silicone rubber sheet.


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## Norvin (Sep 10, 2014)

Time for an update in case anybody is interested.

The 21g La Marzocco basket is deeper than the standard Gaggia double and fits in the portafilter. It gives more headroom to accommodate the shower screen that protrudes from the bottom of the group head.

I had an idea to graft a Rancilio Silvia boiler to the OWC and thanks to @AlbertoG acquired an old busted boiler for the project. After fixing the boiler I stripped the OWC and compared the boilers.









They are roughly the same size, their O rings are almost the same size and there is head room in the case to accommodate it. Unfortunately there were some pretty big problems in the details and I decided not to go ahead with it. It looks like the swap is possible if you are prepared to do a lot of work, but as I had a working boiler I decided that it wasn't worth the hassle.

I bought a pressure gauge and Rancilio articulated wand and had a lot of fun fitting them so all is working well, there is a lot of steaming power with the 1500 watt boiler. It is pretty crowded inside the case now but everything works.

















So I have taken the project about as far as I am willing to go. I still think that once the wrinkles are ironed out and improvements made the OWC makes a fantastic SBDU espresso machine. I would certainly recommend anyone handy enough to take one on, there are only so many challenges in restoring Classics.


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## Hadrer (Sep 26, 2021)

Hello folks,

I just came across this thread as I am looking for Infos on restoring a OWC myself. I bought one in hideous condition but I'm willing to make it the best owc possible.

If you don't mind, let me describe where I stand:

Well, now it turned out someone was playing around with the machine before me and wasn't looking good. By now I have cleaned it (including the inside of the boiler) and replaced all the seals.

That being said: the is a German shop offering the original brewing group seal. Here is the link:

https://www.espressoxxl.de/DICHTUNG-SIEBTRAeGER-r-82x55x5-mm-FUeR-GAGGIA-COFFEE-91

Furthermore I baught a new new pump since the original seems not to work - even after a heavy clean. The EP5 should start working from tomorrow on.

Now my biggest problem atm is that someone has replaced the original switch by a gaggia Classic Coffee switch. I couldn't find a wiring diagram of the OWC which makes it hard to compare the funcions of both switches.

Do you have a wiring diagram or a manual of the OWC you would share? I couldn't access the old gaggia user forum since the domain seems to have expired YESTERDAY! Is this even possible?

Then I realized you wired a PID and a pressure gauge to your OWC (it took me ages to find out that's how you call this model in English - that's why i keep repeating it  ). Would you share your experience and maybe also advice on wiring/connections? I have an IT friend with whom I'd like to program an arduino PID. Still sourcing the parts, though.

Anyways, thank you for sharing your project! I'm highly motivated and willing to achiev something comparable!

Cheers,

Hans (from Germany)


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## Norvin (Sep 10, 2014)

Hadrer said:


> Hello folks,
> 
> I just came across this thread as I am looking for Infos on restoring a OWC myself. I bought one in hideous condition but I'm willing to make it the best owc possible.
> 
> ...


 Thank you for sharing the gasket link, I may buy one someday.

Parts are very hard to find, especially the boiler and switches, they were shared with only a few machines that will be rare too nowadays. The main switches were probably replaced by Classic switches for that reason.

Bad news about the Gaggia Users Group going down. It was a great resource, they had an archive section with manuals and wiring diagrams. It was they that christened the machine the OWC, it was to distinguish the machine from other Gaggias that were confusingly also called the Gaggia Coffee. Some of the people that were very active on that site still pop up on the Home Barista forum so they may be able to help. Unfortunately I can't find a copy of the wiring diagram, I've had a quick look on the net. I know that I had a print out but can't find it, I'll continue looking for it and will post it if I find it. Wiring a PID is easy as it is not too difficult to work out the pickup points.

I have the original manual but it is very generic, no real information in there except for a parts diagram which can be found on the net.

I didn't give many later details of the restoration as there hasn't been much interest shown in this thread; fitting the Rancilio steam wand and pressure gauge was fairly straightforward, Ferrari Espresso do a Rancilio steam arm kit that can be adapted ( edit - https://www.ferrari-espresso.com/product/gaggia-pre-2015-rancilio-steam-wand-v3-conversion-kit/) . I replaced the 1/8 BSP elbow joint on the top of the boiler with a 1/8 BSP 'T' piece and used the extra connection to go to the gauge.

Good luck with the renovation, I will be interested to see how you get on.


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## Hadrer (Sep 26, 2021)

Hey thanks for getting back to me that quickly. Do you have a certain PID brand or did you put one together by yourself? I found a project plan for a gaggia Classic on a blog (1024kb If you are interested in his Setup) that I might try on machine. A pressure gauge, opv spring and maybe a dimmer switch for the pump might follow - depending on me figuring out the replaced switch and the new pump. It's as you put it, my pet project i wante to finish this winter. I'll let you know how it works out...


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## Norvin (Sep 10, 2014)

Hadrer said:


> Hey thanks for getting back to me that quickly. Do you have a certain PID brand or did you put one together by yourself? I found a project plan for a gaggia Classic on a blog (1024kb If you are interested in his Setup) that I might try on machine. A pressure gauge, opv spring and maybe a dimmer switch for the pump might follow - depending on me figuring out the replaced switch and the new pump. It's as you put it, my pet project i wante to finish this winter. I'll let you know how it works out...


 I use a readily available PIDs, I can't see me ever getting involved with Arduinos etc. I used a Rex c100 PID with a K type thermocouple on the OWC, cheap and cheerful but works just fine for me. Be sure to get one with an alarm function if you want it to control the steam as well. Use the more expensive PT100 thermocouple if you want to control temperature to a fraction of a degree. I have a smaller PID on my Classic which also works just fine too, takes up less space, don't know the make but it would not be too hard to find, it is used on other Gaggia's.


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## Hadrer (Sep 26, 2021)

Thank you. I will let you know how it turns out!


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## Norvin (Sep 10, 2014)

LED lights.

Remember, you read it here first.

I got this light as a result of a tip from an engineering forum, it was a tip for illuminating a lathe working area.

You can get these lights cheaply from ebay (about £8-13).









They are made and advertised for lighting a sewing machine working space. They work off the mains, have a magnetic base with an on/off switch. You can get them with varying numbers of LEDs.

Reading about LED mods for my recently acquired Silvia, it occurred to me that it could have another use i.e. they would be suitable for lighting the working area of a coffee machine.

Here is a picture of it on the OWC.









It would not be too difficult to wire the lamp into the coffee machines electrics to come on with machine. The arm is articulated so it can be moved to whatever area suits. I went for the maximum number of LEDs for max lathe illumination but I think there are one's available with fewer LEDs. Rather than clamp it on to the casing, it would be possible to use it for parts to integrate into the machine for a cleaner look.

It clamps to the stainless body of my (soon to be advertised) Classic but not to the stainess ACS Evo leva case 😭


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## r50us68 (Dec 24, 2021)

I also have a own Gaggia and am finding that all roads for information seem to lead to the now now gone Gaggia user group.

From this thread I found this PID set up on eBay and want to double check some things. the search link LCD PID REX-C100 Temperature Controller SSR 40A K Thermocouple Heat Sink K2P7

Are the threads on the OWC boiler(?) compatible?

Will this wiring diagram be compatible with the OWC?


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## Norvin (Sep 10, 2014)

The diagram looks ok but you will need to work out the connection points yourself. Every K type thermocouple that I have seen has a coarse 6mm connector which will not fit on the boiler without modification. You can either take the connector off and trap the end of the thermocouple under a screw on the boiler or get a 4mm PT100 thermocouple, which will fit in place of the brew thermostat.


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## r50us68 (Dec 24, 2021)

I am googling 4mm PT100 thermocouple and wondering is it threaded?

When you say fit int he place of the brew Thermostat, that makes me think it will be threaded


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## r50us68 (Dec 24, 2021)

And to add to my problems, it looks like the Gaggia might have broken

I cannot get water above 120 degree F out of the group head. And it may be steam coming out of the wand, but it is a very fine mist instead of a full blow.

Could the heating element have failed? Or could it be the Thermostat? Would a pid fix this? replace what is broken?


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## Norvin (Sep 10, 2014)

This thread was started as a restoration thread, not a general repair thread. I had left this forum for the other forum but I'll answer a few of your questions in one last post.

The wiring from the brew thermostat to the heater element is usually routed through the steam thermostat as a safety measure. So if the boiler doesn't come up to temperature on either brew or steam, it is likely that the steam thermostat is faulty. You can test by bypassing the steam thermostat by connecting the output from the brew thermostat it directly to the element. It is unlikely but not impossible that the element is faulty, if it is, that's really bad news as replacement boilers for the OWC are not available.

You should sort out the problem before buying a PID. A PID controlling brew only will replace a faulty brew thermostat but not a faulty steam thermostat, or fix a faulty element. The K type thermocouple has a 6mm coarse thread, you can either decrimp the end connector, pull out the wire and trap the little blob of solder on the end under a screw on the boiler or you can drill out and re-tap the thread on the boiler to 6mm coarse (or 1/4" Whitworth which is virtually the same thread) and screw the connector to that, useful if the old thread was stripped or the stub of a snapped off thermostat is blocking the hole.

The end of the thermocouple is threaded, a quick search found this; https://www.ebay.co.uk/itm/274729410407?hash=item3ff7261f67:g:YnMAAOSw~MRgWHd-

if you use the PT100 you will have to change the input type in the PID settings.

I have left the forum now so won't answer any further questions, but other people may.


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## r50us68 (Dec 24, 2021)

Thank you


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## OWCben (1 mo ago)

This thread has been so helpful, I have just bought an OWC for restoration, the boiler was leaking and found two of the four tabs have broken off. I started by making a clamping ring and long studs to the group head base. I used a metal that's too this so it bent as it tightens so will need to try thicker steel. Also has anyone had broken tabs before and how did you resolve it?


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## Alfieboy (Dec 26, 2018)

What do you mean by tabs?


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## OWCben (1 mo ago)

The 4 ears of the boiler that the screw's go through to clamp it to the bottom half


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## Alfieboy (Dec 26, 2018)

OWCben said:


> The 4 ears of the boiler that the screw's go through to clamp it to the bottom half


I would definitely replace that then


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## OWCben (1 mo ago)

Alfieboy said:


> I would definitely replace that then


If only the boilers were available as spares. There's no direct replacement unfortunately


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## Alfieboy (Dec 26, 2018)

I’m guessing from @Norvin pictures you could not substitute a Classic group head and boiler?

He does visit here occasionally so perhaps he could advise?


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## OWCben (1 mo ago)

There is a possibility you can fit the classic boiler but id need the 3 way, the opv and the steam wand valve also. So could be quite costly. 
I have reached out to a welder today who is going to build up new mounting tabs in replacement of the broken ones. 
Measured the ohms of the element today and reads 38ohms as I was expecting


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## Alfieboy (Dec 26, 2018)

OWCben said:


> There is a possibility you can fit the classic boiler but id need the 3 way, the opv and the steam wand valve also. So could be quite costly.
> If you need Classic spares at reasonable cost like that then please ask as I have quite a few
> 
> Neil


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## OWCben (1 mo ago)

Thanks Neil, I'll be in touch if my next try doesn't work out. 
Any idea what the hole spacing is on the new boilers? What's the difference in size between the two?


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## Alfieboy (Dec 26, 2018)

I think the first few photos in this thread show the difference but I can measure one if you’d like


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## OWCben (1 mo ago)

Thanks I did look at the photos and I can see there is a small difference but I was thinking I could make an adapter plate that could put the new boiler on the old head and that would save a lot of cost and less case modifications. When you get a chance that would be useful thank you. Waiting on the result of my next attempt of repair to see if I'll do that or not.


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## Rincewind (Aug 25, 2020)

OWCben said:


> ...I was thinking I could make an adapter plate...


I love adapter plates, such a good idea at times; from engine-gearbox, camera-lens, hard-drive etc. etc. the little (or not so little) adapter plate solves many a sticky issue and is often overlooked; such an arse-saver....and...the best thing is (especially if it works well) that one can make more...making more = ££$$ and helps your fellow man...win, win, win


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## Alfieboy (Dec 26, 2018)

OWCben said:


> Thanks I did look at the photos and I can see there is a small difference but I was thinking I could make an adapter plate that could put the new boiler on the old head and that would save a lot of cost and less case modifications. When you get a chance that would be useful thank you. Waiting on the result of my next attempt of repair to see if I'll do that or not.


I’m measuring 58mm centre to centre for the boiler holes through to the group head


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## OWCben (1 mo ago)

Alfieboy said:


> I’m measuring 58mm centre to centre for the boiler holes through to the group head


Thank you


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## Norvin (Sep 10, 2014)

Just seen this. 
The tabs on my boiler are thin after I machined the boiler face to remove the pitting. It has held so far but I did consider that if they broke off I would need to find a solution. I'm pretty sure that a standard cIassic boiler won't fit the OWC group, I think the sealing faces don't match. I have a spare Silvia boiler and once thought about adapting that, but although it would fit there are a number of details that would take ages to sort out and probably isn't worth the hassle, especially as I have a working boiler.
It may be possible to make a ring that sits on top of the boiler overhanging, four long bolts go through the holes in the ring into the group head. Use Allen bolts as they are high tensile and won't stretch.


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## OWCben (1 mo ago)

Norvin said:


> Just seen this.
> The tabs on my boiler are thin after I machined the boiler face to remove the pitting. It has held so far but I did consider that if they broke off I would need to find a solution. I'm pretty sure that a standard cIassic boiler won't fit the OWC group, I think the sealing faces don't match. I have a spare Silvia boiler and once thought about adapting that, but although it would fit there are a number of details that would take ages to sort out and probably isn't worth the hassle, especially as I have a working boiler.
> It may be possible to make a ring that sits on top of the boiler overhanging, four long bolts go through the holes in the ring into the group head. Use Allen bolts as they are high tensile and won't stretch.


Yes your right the new classic boiler won't go on the coffee group. But like a carburettor adaptor plate i can make a plate to bolt both pieces together. And so far I have made a 3mm thick steel plate that clamps the boiler down via long studs. They shouldn't need to be high tensile, I wouldn't have thought, Stainless bolts that were originally used are only around 4.8 grade so I have used stainless M5 threaded rod the same. When the old OWC comes back from the welders it should have a mating face again. Then fingers crossed it all holds pressure.


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## Norvin (Sep 10, 2014)

OWCben said:


> Yes your right the new classic boiler won't go on the coffee group. But like a carburettor adaptor plate i can make a plate to bolt both pieces together. And so far I have made a 3mm thick steel plate that clamps the boiler down via long studs. They shouldn't need to be high tensile, I wouldn't have thought, Stainless bolts that were originally used are only around 4.8 grade so I have used stainless M5 threaded rod the same. When the old OWC comes back from the welders it should have a mating face again. Then fingers crossed it all holds pressure.


I suggested high tensile as they will be quite long and they will be relatively cool outside of the boiler. The different expansions of the cool steel stud compared to the hot aluminium boiler may cause problems but probably won't.
Good luck with the project, watching with interest.


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## supernova1477 (Jan 7, 2021)

Hello again,

I saw that some of you were looking for the manual and I came across one in Italian. There is a schematic showing all the parts and connections if that is helpful, and if you happen to know Italian, even better!

Gaggia Old White Coffee Manual (Italian)


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## OWCben (1 mo ago)

supernova1477 said:


> Hello again,
> 
> I saw that some of you were looking for the manual and I came across one in Italian. There is a schematic showing all the parts and connections if that is helpful, and if you happen to know Italian, even better!
> 
> Gaggia Old White Coffee Manual (Italian)


That's amazing thanks!! I have been looking for weeks for one of these and then bam someone pops up and posts it 😂. And it's in 4 languages including English which is even better, no need to learn Italian!


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## Norvin (Sep 10, 2014)

I have a manual, which came with the machine. It has a slightly different cover.


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## OWCben (1 mo ago)

Norvin said:


> I suggested high tensile as they will be quite long and they will be relatively cool outside of the boiler. The different expansions of the cool steel stud compared to the hot aluminium boiler may cause problems but probably won't.
> Good luck with the project, watching with interest.


Hi Norvin. GREAT SUCCESS AT LAST 🎉.

It is finally working. Now trying to learn how to use it haha. It's my first espresso machine, so I have done my best to dial it in this afternoon with the MDF grinder. Turned out ok, can improve it muchly for sure. I have channelling in the same place every time in the puck. Do you know if the modern Gaggia classic screens fit? Might double up the screen with an IMS one. It's got some steam power too hasn't it, wow.



https://youtube.com/@benfitch8795



Feel free to look on my YouTube at what I've uploaded so far.


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## Norvin (Sep 10, 2014)

Great stuff.

I've used that Quick Steel before and it's good stuff. I tried to repair deep pitting of the mating surface of my boiler with epoxy but it didn't hold, but it may work for you as it won't get wet.

The pitting and channelling of the puck is probably due to the velocity of the water exiting the head. You can tame it by opening out the hole and fitting a screen with a baffle. I have tried the screen from my Rancilio Silvia and it fits much better than the Fracino (?) one that is currently fitted. Use it with the standard screen. The classic screen will fit, I can't see the need for an IMS screen, the Rancilio type will be better.

The condition of your OWC is really great, much better than mine, pity about the boiler.

The machine as it stands has limitations, you really should try some of the modifications as they improve the standard machine so much. If you have the aluminium portafilter that came with the OWC, a standard Gaggia one will fit and is so much better. 
Here is a picture of the screens and portafilters, large screen is from the Ranciio.


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## OWCben (1 mo ago)

Thank you. In the end the quick silver repair didn't work for me but I have just uploaded a video of how I had it welded and faced it off in my lathe. 
I have bought another stock Gaggia shower screen and I'm going to try double them up. See how that works, I'm going to do your trick and countersink the outlet hole to reduce the water jetting coming out. I think I'll get a gauge in it to set-up the opv. 
Thanks for staring this thread I've found it such a help. 👍🏻


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