Hi,

My Rocket Appartamento, purchased in 2016, keeps having the boiler turn off randomly, usually every few days. I open the machine up and wiggle the wires connected to the thermostat, the one with the thicker black wires, turn the machine back on and it starts to heat again, to only fail again a few days later. The thermostats themselves are not tripped; the button is still pushed in, and nothing happens when I try to push it in. I've changed the thermostats (twice!). I also snipped and re-pinned the black wire connectors that go to the thermostat because I thought maybe they were a bit corroded or not making perfect connection. I noticed that some of the wire insulation looked melted and the plastic covers over the terminals broke away when I changed out the thermostat the first time. I still have the same issue and it is quickly fixed by taking the top of the machine off, wiggling the wires a bit and it starts heating again.

I have NOT replaced the pressurestat. I have read many threads on here recommending that, but I do not think it is that because it never spikes high or anything. I have it set where I read around .8 bar on the gauge (my temp is 202-204 on my grouphead thermometer).

I've also read that it may be a relay in the control board. Although I have soldered before, I would probably just go for the control board replacement, rather than trying to source the component.

I've tried a bunch of things and was looking to see any other ideas before going the new control board route.

thanks.

This will likely make no sense, but if you do everything but wiggle the wires, does the problem go away? When you wiggle the wires does anything else move? Do you have a voltmeter?

Ira

Almost certainly pressostat contacts burning.
Wiggling the wires just happens to move the pressostat just enough for it to re-make contact. I believe you've confirmed that the machine is wired with the pressostat in series with the element, so the pressostat contacts are breaking the full load. You will be replacing that pressostat, or at least it's microswitch every few years.

Next time you catch it happening, just tap the pressostat lightly with the plastic end of a screwdriver and see if that re-makes the circuit, that might eliminate the "wiggling the wires" theory. (Or it might prove it, maybe it's not the p-stat).

Hi, thanks for your replies, they made me dig a bit deeper. When the boiler turned off again, I was sure to only "wiggle" near the thermostat. I noticed the leg on the thermostat was a bit "loose". I removed it from the boiler and hooked up my Fluke multimeter to each leg of the thermostat. When I wiggled the legs I get from .2ohms to ~600kohms to infinite and very erratic.

I had an original thermostat that I kept (I changed both out when I had one that kept tripping) and it showed good continuity and the legs weren't "loose". I put it in my machine and it seems to be working fine, for now. I'm a bit stumped, maybe I had a bad new thermostat that I replaced the original failing one with? When my original thermostat failed, it just kept tripping prematurely, and I could push the buttom to reset it.

I'll keep an eye on it and will tap the pstat if I have an issue again to see. thanks again.

lapadog wrote: I'll keep an eye on it and will tap the pstat if I have an issue again to see. thanks again.

I think you fixed it at the wiggly leg. Your p-stat is probably fine for a while longer.

Well just to update this post for anybody else having issues.

Turned out the root cause was my control board. Eventually it got to the point where I "caught it" overheating (pressure >2bar and still climbing). It got to the point where it was happening regularly. I replaced the pstat and same issue. I then bought a new control board and put it in and everything's been good for about 2 weeks. Just for other folks, my wiring was low voltage to the pstat and then heating elements on/off from the relay in the board. My Appartamento is about 6.5 years old. I thought about redoing the wiring like I saw posted here, but decided to keep it for now.

If replacing the control board solved the problem then it might likely be a relay on that board that could possibly be identified by the same tapping with the back of a plastic handled screwdriver as John mentioned in his post.

Replacing those relays is usually a simple procedure. Also thermal devices have components or elements that are riveted together, if the riveting process had incomplete pressure applied, the interlocking components might become loose and thus making intermittent contact.