CRW Senior Member Joined: 24 May 2012 Posts: 35 Location: PA Expertise: I love coffee
Posted Sun Oct 21, 2012, 5:25pm Subject: Re: trouble with Gaggia Classic, and questions
I just took off the feed tube from the fitting underneath. Visual inspection, looks good. Blew air thru it with my mouth against resistance, no leaks. used as straw, sucked in water from cup, no pressure leaks. Took other feed tube from housing floor fitting/clamp, inspection to point where it disappears under pump and I can't see it. Looks good. As I moved that tube around, the back pressure kept the water in the tube--it didn't leak out. Manually blowing or sucking didn't reveal any loss of pressure or leaking. Put it back together, refilled reservoir, turned machine on, and even though feed tube was now empty/full of air at the bottom 6" or so, there was no trouble running the pump and sucking up water. Ran water thru the steam wand and then the group head. Now it has sat for about an hour heating up, and I just made a coffee with no trouble. I'll try again in another 30-40 minutes and see it it will work again. This thing is a mystery...
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,189 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Sun Oct 21, 2012, 8:12pm Subject: Re: trouble with Gaggia Classic, and questions
I get some air in the line when I clean the tank. No problem for the pump to pull it through and up and out. Of course, that is into the tank and if I know air is getting into the tank, then I open the steam vent and that bleeds any air out. Also opening the steam valve/wand lets the pump run easily, no or little pressure.
An OPV leak should not suck air in, unless the system was cooling and lowering the internal pressure. No real experience, just thinking out loud.
Did you test the valve or fitting between the hose? Could you temporarily eliminate it by putting a piece of straight tubing between the 2 halves?
When you see air in the line and have problems it is before the pump?? If so, then it seems that it would be difficult for the pump to let air in retrograde. Assuming that air rises in the system, I am looking for the leak or problem lower in the line.
tracerbullet Senior Member Joined: 13 Feb 2012 Posts: 152 Location: Saint Paul Expertise: I love coffee
Posted Mon Oct 22, 2012, 10:48am Subject: Re: trouble with Gaggia Classic, and questions
I think you're on the right track looking for air coming in. It's possible that fiddling w/ the tubing created a temporary fix - doing it again might re-open an air leak?
A new machine will have a solid clear silicone soft tube going from the bottom of the reservoir, through the floor of the machine, up to the pump, without any breaks or fittings. OPV blow-off is a black high temp hose going from the OPV to a fitting in the floor of the machine and left to drip into the reservoir from there. A fitting on the intake tube should be OK but it's not needed and if it's an area in question it might be worth just getting rid of and running a straight shot. As for the OPV fitting having an additional tube after the fitting into the reservoir I can't see it being needed nor hurting anything. Also, I mentioned it earlier, the intake tube should have a V-notch in the bottom, I'd verify that to be sure you aren't stalling the pump trying to suck up the floor of the reservoir itself.
You mentioned it sitting for 8 years, if it's not a tubing related issue it could be the pump itself. That's a long time for anything w/ rubber parts to sit around. And / or if your'e in an area where it may have seen freezing temps in a box in a garage or something.
If it was my machine I'd replace the tube to the pump and see if that solves it. If not I'd be shopping for a pump. I cant' be certain that's the issue but that's what I'd be expecting to do.
BTW, the intake tube has a 5mm ID. If you can't find metric, 3/16" is a touch smaller and will stretch to fit. Any tubing OK for water will do, don't have to worry about a temperature or pressure rating.
CRW Senior Member Joined: 24 May 2012 Posts: 35 Location: PA Expertise: I love coffee
Posted Fri Nov 2, 2012, 11:59am Subject: Re: trouble with Gaggia Classic, and questions
nothing was really found one way or another. There's no leak from the end of the intake tube, into the pump. It only causes a problem when it's been on for awhile, idle, and I try to make an espresso. When I first turn it on, and it's cold, it always works. One time I was having trouble kind of late at night, and I decided to give up and turned it off. There was air in the line, it wouldn't draw water. The next morning I turned it on and it worked fine. I stopped messing around with it for now. If I make a few coffees close together and then turn it off for while, it seems to work. But I'm convinced it's not a problem with the tubing. If the pump was starting to go bad, would it lose pressure? And then, if it wasn't strong enough to pull more water, that might be the problem? I don't know. I just know it only gives me trouble when it's been heated up awhile...
Posted Fri Nov 2, 2012, 12:09pm Subject: Re: trouble with Gaggia Classic, and questions
Did you check the routing of the pipes inside? Maybe your boiler is running hot* (or you are using the steam switch) and the water in one of the pipes is boiling?
I mention this because with my PID'd Gaggia Classic, the set point to get 200 F water at the puck was about 218F - which is obv. above boiling, so steam can be created in normal use.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,189 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Fri Nov 2, 2012, 8:07pm Subject: Re: trouble with Gaggia Classic, and questions
I think that the water/air is that between the cool tank and the pump. If that is the case, I would change to the clear silicone hose, pump back into tank, and eliminate extra fittings.
CRW Senior Member Joined: 24 May 2012 Posts: 35 Location: PA Expertise: I love coffee
Posted Mon Nov 5, 2012, 12:01pm Subject: Re: trouble with Gaggia Classic, and questions
OK, so I opened it up again while it's on, and noticed that when I run water (not steam) out of the steam wand, it dips inside the box, around the steam wand valve. Didn't notice this before. It doesn't seem to drip when I'm making steam for milk, but I never looked inside at that point before. Could there be a leak then in that valve/knob assembly, that may be leaking air into the system?
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,189 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Mon Nov 5, 2012, 7:39pm Subject: Re: trouble with Gaggia Classic, and questions
D4F Said:
How much does the steam wand drip? Are you losing water and then turning on the pump to a slightly empty tank? Put a cup under the wand when you are leaving it on for while and quantify? Resistance against the pump can make noise vary.
Could you be losing water and or steam inside when hot and pulling in air with cooling? After it is completely cool open the steam valve and then turn on the pump. Water immediately, or some air?
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