seedlings Senior Member Joined: 6 Jun 2007 Posts: 252 Location: Saint Joseph, MO 64506 Expertise: I love coffee
Espresso: Nuova Simonelli Premier V Grinder: Rossi RR45 Vac Pot: Cory DCU / DCL Rubberless Drip: Newco Air Pot Roaster: CoffeeAir II
Posted Thu Oct 23, 2008, 6:37am Subject: Another Gaggia Preheat / Pressure Mod
Note: There is no new thinking in these modifications. I read about them in other threads. This is just how it turned out on my machine.
The Gaggia Espresso espresso machine has 2 strikes against it. First, the inlet to the boiler is right next to the grouphead, so shots err from bitter to sour all things being equal. The incoming cold water mixes with the hot water at the base of the boiler as soon as brewing starts, so the brew will often start too hot and cool 10 degrees pretty quick. (I've not measured on my machine, just going on what I've read in other threads. Stupid me, I jumped right in without baselining everything first.) 1/4" copper pipe was installed from the pump and wound around the boiler several times to preheat the water before it goes into the boiler. Hopefully this will dramatically stabilize the brew temperature.
Second, the vibe pump puts out up to 15 bar of pressure while only 9 is required for a good shot. I've found myself grinding finer and tamping harder, only to have the coffee gush through too quickly. I've previously cleaned the over pressure valve (OPV) and now it is operational. The plan is monitor the pump pressure with a gauge installed between the pump and the preheat tubing. This isn't the ideal place for a gauge, but it will still give a good idea of the brew pressure.
Posted Thu Oct 23, 2008, 8:22am Subject: Re: Another Gaggia Preheat / Pressure Mod
Hi CHAD, I did the same mod on a Proteo Romanza/Gaggia Coffee and it certainly did increase the shot stability and shortened the cycling time. Regarding the OPV, AFAIK the valve at the pump is set at 11 bar and is not adjustable, it is really a safety valve. If you want to install an adjustable OPV you need one of these Click Here (www.shop.partsguru.com) but your video shows a pressure of 150 psi which is 10.34 bar so not too far off. If your pf has removable spouts mount your gauge on it and measure the pressure at the group. If you are not already a member check out http://groups.yahoo.com/group/Gaggia/ for lots of information on mods for your Gaggia.
seedlings Senior Member Joined: 6 Jun 2007 Posts: 252 Location: Saint Joseph, MO 64506 Expertise: I love coffee
Espresso: Nuova Simonelli Premier V Grinder: Rossi RR45 Vac Pot: Cory DCU / DCL Rubberless Drip: Newco Air Pot Roaster: CoffeeAir II
Posted Thu Oct 23, 2008, 11:45am Subject: Re: Another Gaggia Preheat / Pressure Mod
Dink0617 Said:
Hi CHAD, I did the same mod on a Proteo Romanza/Gaggia Coffee and it certainly did increase the shot stability and shortened the cycling time. Regarding the OPV, AFAIK the valve at the pump is set at 11 bar and is not adjustable, it is really a safety valve. If you want to install an adjustable OPV you need one of these Click Here (www.shop.partsguru.com) but your video shows a pressure of 150 psi which is 10.34 bar so not too far off. If your pf has removable spouts mount your gauge on it and measure the pressure at the group. If you are not already a member check out http://groups.yahoo.com/group/Gaggia/ for lots of information on mods for your Gaggia.
Yes, I have your thread favorited along with the home-barista thread with the custom aluminum pre-boiler. Initially I just wanted to check the pressure, but after seeing your thread, I figured the preheat tube would be an easy addition since I had some tubing laying around (copper is expensive!). I wanted to use all 10 feet, like you did, but... we'll see.
You say the OPV is not adjustable? Do you mean that loosening or tightening the screw (that presses against a spring, compressing a little ball) won't change the ~11 bar pressure? I find that I can change the pressure. It's not a fine-tune control, but a general control. I could up the pressure by 3 bar if I want, or lower it a little more too.
The one in the picture is not the one from my machine, but mine works identically. I had to take it apart and lubricate it so that it worked.
Thanks for the invite at the Gaggia group. I just joined!
jason_casale Senior Member Joined: 11 Dec 2003 Posts: 111 Location: Mesa Arizona Expertise: I live coffee
Espresso: La Spaziale S2 Grinder: Cimbali Max Vac Pot: Hario Drip: Techno Vorm Roaster: 3 Kilo Drum Roaster.
Posted Fri Oct 24, 2008, 11:40pm Subject: Re: Another Gaggia Preheat / Pressure Mod
Hey what size copper tube did you use to do this? How did you get the fittings on the tubing. The only reason I ask is because this could probably be done to a silvia making it more stable. I have a silvia with a PID Thanks jason
seedlings Senior Member Joined: 6 Jun 2007 Posts: 252 Location: Saint Joseph, MO 64506 Expertise: I love coffee
Espresso: Nuova Simonelli Premier V Grinder: Rossi RR45 Vac Pot: Cory DCU / DCL Rubberless Drip: Newco Air Pot Roaster: CoffeeAir II
Posted Sun Oct 26, 2008, 5:02pm Subject: Re: Another Gaggia Preheat / Pressure Mod
jason_casale Said:
Hey what size copper tube did you use to do this? How did you get the fittings on the tubing. The only reason I ask is because this could probably be done to a silvia making it more stable. I have a silvia with a PID Thanks jason
Hey, Jason. The tubing is 1/4" copper. The fittings are universal, brass, and designed for either 1/4" copper or plastic tubing. You can pick them up at any hardware store, Home Depot or Lowes.
It is a very tight squeeze to attach the fittings without leaks. You need to "double wrench" the fittings tight. That means use one wrench on the base of the fitting and the other wrench to tighten the compression nut. Leverage the wrenches together to tighten/loosen. Tricky.
sportychop Senior Member Joined: 14 Feb 2008 Posts: 50 Location: Ft Worth TX Expertise: I live coffee
Espresso: Brewtus II, Gaggia Classic,... Grinder: Super Jolly, Nuova Simonelli...
Posted Wed Dec 24, 2008, 1:21pm Subject: Re: Another Gaggia Preheat / Pressure Mod
Ok, I would love to post this anonymously but the forum will not allow for that. Please help out a poor stupid jerk that tried to do this with a brand new Classic and wound up with a 500.00 fountain. My wife deserves an award for not killing me. In hind sight it was pretty naive to think I could or should tackle this as my first ever plumbing project. I am not doing the gauge, just the preheating tubing. I got the copper tubing wrapped around pretty good but was not able to get it as tight as yours looks. The fittings and tubing I purchased look the same. I used a tubing cutter, but when I got everything put together I had great difficulty getting the fittings over the tube ends. I even broke a couple of the fittings because they got stuck on the tube and I had to try to pry them off. I was not able to get them to seal, on either the plastic side or the copper side, even under no load, no matter how tight I made them. I was afraid I would strip them if I went any. Maybe I deformed the tubing too much to allow for a seal, I'm not sure. Maybe I did not get it straight enough and the joints. Any thoughts or advice you can offer would be great. I still want to do this but I am now obviously reluctant to try again. Did you have issues with leaks that you had to tighten up? On a side note, I was smart enough to assume my project would be successful, so I cut the original plastic tube. I have put everything back together and used refrigerator ice maker tubing to replace the original line. It seems fine for a day or so but then tiny fractures form at the boiler base. I read a few threads and it seems I should be looking for Teflon tubing anyone know a source for this? I looked at many of the common online parts places but all I could find was vinyl tubing, the melty stuff.
Please keep the laughing and jeers to yourself, I'm still feeling a little self concious. really any help would be appreciated.
Quit kicking yourself buddy...most of us have been there.
Go over to Yahoo>>>>Groups>>>>Gaggia. Join up, relax it won't hurt a bit, there you will find links to suppliers that have all the parts you need. And several posts on the type repairs you are dealing with.
Posted Wed Dec 24, 2008, 7:47pm Subject: Re: Another Gaggia Preheat / Pressure Mod
I give you credit for tackling this project. However, I wouldn't have done it on a new machine, as you may have been perfectly happy with it stock. Maybe the steam wand mod.
Scott
-Scott Coffee smells like freshly ground heaven. ~Jessi Lane Adams
Posted Wed Jan 14, 2009, 3:04pm Subject: Re: Another Gaggia Preheat / Pressure Mod
sportychop Said:
I read a few threads and it seems I should be looking for Teflon tubing anyone know a source for this? I looked at many of the common online parts places but all I could find was vinyl tubing, the melty stuff.
I don't know exactly what size you need, but here's a link to 1/4" ID high temp FDA approved Teflon tubing that is rated to 250 psi. Click Here (www.mcmaster.com)
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