Giotto overpressure problem - boiler won't stop heating - Page 3

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
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erics
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Joined: 19 years ago

#21: Post by erics »

Some rambling thoughts -

It would take a whole bunch of water to fill the boiler to the extent that would cause a boiler safety valve to "blow" - you would notice this in the level of water in the reservoir. A leak in the hx would be a consistent leak - not one that randomly chooses to open/close. Yes, boiler fill solenoids can leak BUT there is a fairly large drop in brew pressure (I realize you do not have a brew pressure gage) when the solenoid is open that you would hear a different pump sound and notice it in the shot flow.

Troubleshooting efforts would benefit from a temporary small wattage light connected to your pstat. One leg of the light would go to a neutral connection and the other to the normally closed terminal on the pstat. When the pstat is sending power to the heating element, the light would be on. Normal operation of an idling machine would have this light on for about 10 seconds and off for about 90 seconds.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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Juanjo
Posts: 153
Joined: 15 years ago

#22: Post by Juanjo »

cannonfodder wrote:The diaphragm on pressurestats will stiffen and can scale over time. They will all eventually fail which is what it sounds like you have. You can take the pressurestat off, put a little vinegar in it and let it soak for a while, then rinse it out to see if that fixes it. Sometimes simply tapping on top of it will un-stick it but if it happens again, you would be best to clean it or replace it. The are relatively inexpensive.
I had that problem, but mine was beyond repair..
cheers,
Juanjo

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cannonfodder
Team HB
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#23: Post by cannonfodder »

You dont need to fill the boiler to blow the over pressure valve. If the boiler fill solenoid was sticking open or leaking, or you had a ruptured HX, it would pump water into the boiler but run your boiler pressure through the roof. You are brewing at 9 bars and pumping 9 bars of pressure into the boiler with relatively low water flow. I had a two group with a ruptured HX in one group. The boiler would fill with a little water but my boiler pressure gauge would shoot up like a rocket.
Dave Stephens

reno rs
Posts: 13
Joined: 15 years ago

#24: Post by reno rs »

I'm going to swap my fill solenoid to see if that's the problem. If that doesn't work, how do I check for a leaking/ruptured HX? And if that is the problem, is it fixable or would I need a whole new boiler assembly?

Cheers,

matt

SNielsen (original poster)
Posts: 26
Joined: 16 years ago

#25: Post by SNielsen (original poster) »

Hey Guys,
The latest on our machine is that the Gicar was kaput and has been replaced. Faema Toronto did this for C$300 plus C$50 labour for testing and installation. I thought this was pretty reasonable, and saved me the risk of a misdiagnosis and/or blowing the Gicar and being left with a non-refundable item. The repair tech was very helpful and quick to get the machine back to us -- one day turnaround! If anyone lives near Toronto, go see John at Faema on Dupont -- highly recommended.

I talked to John about the P-stat, and he said that the model that's in our machine (Jaeger brand) has been very prone to calcification. Almost all of them fail sooner or later. He was surprised that ours lasted as long as it did. As a matter of course, they now recommend replacing all the Jaeger models with newer ones that do not have this problem. He tested ours and it worked fine. But this is just a $75 part, and so I had him replace the Jaeger with the better model -- this will preempt the inevitable and save me some hassle somewhere down the road. Preventive maintenance, in other words. Below is a pic of the old p-stat that was in our machine.

Another thing that was interesting, and that may help those of you with overfilling problems, is that he found that the boiler water level sensor was completely covered by the plastic sleeve, causing the boiler to overfill. Now, this was probably my fault, as I took the metal rod out last week during my diagnostic poking and prodding. I reinserted it the way I thought was correct, and obviously did it wrong and pushed the plastic sleeve too far down the rod. So if any of you have had this sensor rod out, and are having overfilling problems, it may be a good idea to check the plastic sleeve and make sure it isn't pushed down too far.

Hope this is helpful.....and thanks again to all for their input and assistance.

Cheers,
Svend

edit: just got a note from John at Faema, and the new pstat that he put in is a Ma-Ter model. He says these outlast the Jaegers by far.


reno rs
Posts: 13
Joined: 15 years ago

#26: Post by reno rs »

I should have updated this long ago but anyway... my machine has been functioning flawlessly for almost a year now. I pull 2+ shots nearly everyday and have had nary an issue.

My problem was caused by having the boiler fill solenoid installed backwards i.e. the direction of flow for the solenoid was leading away from the boiler. The pump pressure is great enough (not surprising at 9 or bars) to force it's way through a closed solenoid because of the solenoid design. Moral of the story is, be sure to note the flow direction of the solenoid when reassembling your machine.

Big thanks to Eric S. for the countless emails and time he spent with me in diagnosing the problem. I think we still disagree to some extent but his knowledge and willingness to help is an asset to this community.

Cheers,

Matt

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