# Setting the brew pressure on an old Gaggia



## PACMAN (Feb 11, 2021)

Whilst I'm not collecting coffee machines, I seem to have 2 now, yet no more than 2 months ago, I didn't have any (well, except my B2C machine). Anyway, my GC is pretty much sorted, OPV adjusted, PID fitted, pressure gauge fitted - all is good, but my 'new' Gaggia is just starting out on its modding journey. It's the 1980s model I have just acquired: one of these in black (pic taken from here: https://www.gaggia.com/legacy/) :










I'm in the process of dismantling, cleaning etc etc and am now wondering if it is possible to adjust the brew pressure. From what I can make out, it seems to have pretty much the same internals as a Gaggia Coffee Classic, just in a different shell. I haven't yet got the stage of 'firing it up' as I need some O rings etc, but if there is any way I can adjust the brew pressure, now's the time to do it. From what I can make out, there is some form of overpressure device on the water pump and also some form of pressure device within the brew head. Can either (or both) be modded to give approx 9 bar pressure?


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## Alfieboy (Dec 26, 2018)

PACMAN said:


> Whilst I'm not collecting coffee machines, I seem to have 2 now, yet no more than 2 months ago, I didn't have any (well, except my B2C machine). Anyway, my GC is pretty much sorted, OPV adjusted, PID fitted, pressure gauge fitted - all is good, but my 'new' Gaggia is just starting out on its modding journey. It's the 1980s model I have just acquired: one of these in black (pic taken from here: https://www.gaggia.com/legacy/) :
> 
> 
> 
> I'm in the process of dismantling, cleaning etc etc and am now wondering if it is possible to adjust the brew pressure. From what I can make out, it seems to have pretty much the same internals as a Gaggia Coffee Classic, just in a different shell. I haven't yet got the stage of 'firing it up' as I need some O rings etc, but if there is any way I can adjust the brew pressure, now's the time to do it. From what I can make out, there is some form of overpressure device on the water pump and also some form of pressure device within the brew head. Can either (or both) be modded to give approx 9 bar pressure?


 If you're going to strip it down then setting the OPV will be done after that

They appear to have an OPV like in some of the Baby Models so on the pump outlet

This is from MrBean2Cup


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## HDAV (Dec 28, 2012)

You would need to adjust item 47 I'm not aware of a way to do this


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## Alfieboy (Dec 26, 2018)

HDAV said:


> You would need to adjust item 47 I'm not aware of a way to do this


 It's an Allen key from below on the Gaggia Baby I have


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## PACMAN (Feb 11, 2021)

There is a small slotted 'screw' in the base of mine which then holds back a spring, certainly no room for a hex key but there is access from below if the water tank is removed. It doesn't have as much adjustment range as a 'normal' Gaggia OPV but maybe with a bit of trial and error, I can see what range I can get on it, then take a bit of length off the spring and try again - a one way modification if I get it wrong!! Edited to say - just found a pic on the MrBean2Cup site:










What does the spring and little rubber bung in the brew head do? It seems to be set at 5.5 Bar - https://www.mrbean2cup.co.uk/gaggia-brewing-valve-55-bar-assy so I guess this won't have much if any effect on the actual brew pressure other than to stop water coming through until it gets to 5.5 Bar.


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## PACMAN (Feb 11, 2021)

Here's the OPV in its component pieces (prior to being descaled and cleaned) - now to try and see if I can get any adjustment on it once it's fitted and everything's back together...


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## Alfieboy (Dec 26, 2018)

This is the one from the Baby, a 2005 I think going down into the tank which is where the Allen Key access is


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## PACMAN (Feb 11, 2021)

Well, I'm happy to report that yes, you can adjust the pressure and yes, there is enough thread to unscrew it far enough to get a reading of 9 Bar (with a blind basket in place - I don't have a PF pressure gauge - only the one I bought from @FairRecycler). Only trouble was - after setting the pressure, and because I'd used the blind basket, I had problems releasing the PF! Ha Ha, managed to get it off in the end by removing the 'fill' pipe and letting the water drain from the boiler sufficient to get the PF undone.


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## EspressoHampshire (12 mo ago)

@PACMAN

Did you cut the spring down or just release the screw? How many turns did it take to get the 9 bar pressure?


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## PACMAN (Feb 11, 2021)

EspressoHampshire said:


> @PACMAN
> 
> Did you cut the spring down or just release the screw? How many turns did it take to get the 9 bar pressure?


 I didn't cut the spring - left it as it was, but I did 'back off' the screw. I couldn't say how many turns as I completely took it to pieces to clean, then reassembled and used my pressure gauge to set it.


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## EspressoHampshire (12 mo ago)

Thanks for the reply, very much appreciated.

Got a Gaggia Coffee Deluxe on the way. Will eventually put in a PID and built in gauge for the pre infusion but for the time being I'm planning to do exactly the same as yourself.


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## DeLorean58 (12 mo ago)

So glad I found this. I just got done converting my old Gaggia Coffee to a classic by means of KitchenAid ProLine grouphead, solenoid, and boiler assembly. Bought the parts for the cost of a new grouphead alone. I had to make due with the safety valve in their for now. I was going to convert it to a classic pro style OPV, but I may hold off for now, as it all is working as is right now. I think I'll do the Gaggiuino mod to mine rather than going PID.


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