Rocket Appartamento not heating - Page 4

May 12th, 2022, 3:53 pm

JRising wrote:"EDIT: The over-pressure valve just whistled... Does that mean it's the P-stat,"

So the safety is working, it is shutting the element power off when the boiler actually is overheating.
Can you not just adjust the p-stat down? Have it shutting the element off at about 1.2 bar?

Or have you adjusted it, and it is normally shutting the element off at 1.2, but sometimes it doesn't open (shut off) and allows the boiler to overheat. If this is the case, then the pressostat is at fault, either the contacts are welding closed because of carbon build-up (unlikely), or the diaphragm is not moving easily.

It looks more like your second option. I didn't have to adjust it, as it turns on the element at 1.1 and shuts it off at 1.3, and has been doing so without any issue for the last 15 months or so.

#32: Post by **JRising** » May 13th, 2022, 7:39 am

Well, if you can catch it "still heating" at 1.4 Bar, tap the p-stat with the plastic end of a screwdriver and see if that "un-seizes" it.
If you have a clamp-on ammeter, you can perch it high in the machine clamped around one of the p-stat wires, that's a safe way to monitor power in a live machine.

May 13th, 2022, 8:52 am

I don't have any, but I purchased a new Mater P-stat and will see if it still overheats once I've replaced it. Does it make any sense to upgrade to a Sirai? Is that feasible at all on an Appartamento?

#34: Post by **JRising** » May 13th, 2022, 9:23 am

I don't think the Sirai would fit into the space without some serious pipe bending... Possibly so much pipe bending as would be needed to move the boiler, if you want the p-stat inside the body.

Putting in a solid state relay to protect the p-stat might be a more feasible "Next upgrade".

May 17th, 2022, 7:50 pm

I swapped out the old P-stat for a new one I got today. So far so good. I'll report back to say if that fixed the problem. One question though: the new P-stat cycles every 20 seconds or so, which is like twice as often as the old one. Won't that wear it out prematurely? Is it possible to alter the bandwidth?

#36: Post by **Nunas** » May 17th, 2022, 8:17 pm

The new one is cycling faster because as the P-stats wear, the dead band increases. A new P-stat will be "tight", but, as you suspect, over time, it will wear and the dead band will widen.

May 19th, 2022, 8:21 am

The machine has been running for two days without a hiccup, so it seems swapping out the P-stat did the trick. Thank you all.

Now I'd like to find a way to replace the faulty relay on the old Control Board so I have a spare, and I might take up JRising's suggestion and put in an SSR...