External firebird boiler intermittently turning on and off

chabsey

I've got a relatively new (~2 years old) and recently serviced (today) Firebird boiler which is controlled by a EPH T37 HW controller in the house. While the zoned heating and hot water functions all continue to work without a problem we've noticed that we can hear the boiler turn on and off briefly, a few times an hour for no reason (we've had no reason for the heat to be on and use the hot water once a day).

Our installer looked at it briefly and said it could be an electrical issue but that we should get it serviced first to rule that out. So today we got it serviced and the issue persists.

My layman's guess was that it could be the frost protection gone mad, because it's so unusually warm the last while it is triggering it for some reason. But we checked and it's set to come on at 5 degrees so shouldn't be the cause. We did a factory reset on the controller but with no success, the issue continues. We think (but aren't sure) it seems to have coincided with the recent warm weather.

Anyone got any ideas or pointers as to what could be causing this issue?

jimf

if you have motorised valves operating the zones it could be a faulty micro switch sticking

Wearb

Your service person should have been able to diagnose the problem. It would not be part of a service, but it is the sort of breakdown call we sometimes get. After ruling out Jimf's suggestion, I'd start by disconnecting the programmer and the frost stat. It might even be chewed wires somewhere.