I have a 2003 Giotto Classic, which after about 45 minutes loses pressure. A sharp rap on the side of the machine restores operation for about 15 minutes. Thinking it was due to a mechanical relay, I replaced the heater relay RL3, with no effect. Is there an element on the controller board which more commonly fails as it heats up?

Thanks for your help.
Gary

That sounds more like a problem with the pressurestat contacts staying open. That could be a pressurestat problem itself or possibly scale in the line not allowing the pressurestat to close its contacts or a bad diaphragm. Something like that.

Could also be the vacuum valve or safety pressure release valve sticking slightly open. A small mirror held next to valves and fitting will show any 'ghost' leaks.

PS - What I found with the La Cimbali Junior is that overfilling the boiler will sometimes cause the vacuum valve to leak a bit until the level drops.

What happens if you open the steam valve for some seconds after 30 minutes? The same ?

I have a 2002 ECM Giotto, which may or may not be like yours. I understand that back then they came out of the factory with a little variability.

Be sure to check that your reservoir sensor probe is making good contact. Even when the reservoir is full, a poor contact will cause your symptom - green light on, no heat, and if you actuate the lever, no pump. And a rap on the machine will often wake it back up for a while.

You can clean this contact:


Also to test, you can temporarily remove the reservoir sensor wire under this contact (pictured below), then reattach somewhere to a good ground and see if that fixes it.




*Edit: I originally slightly misremembered my machine's age. Checked and it's 2002 not 2003 (SN# 20020402109) Mine has the GiCAR 9.9.04.77G, which feeds low current through the pStat and has an internal heater relay (R1).

I eventually had to have my Giotto pressurestat and high limit replaced. So I guess my situation was different, had to poke the red button to get the machine to turn back on.