Firebird Firing of own accord.

[jackplumb]

I,ve got a Firebird (non combi)with a strange problem, it fires at night there is no call for heat from either stats and the owner says that the boiler makes a roaring noise. If they overide the programmer the boiler noise reverts back to normal. It sounds as if the heat is not getting away from the boiler and once they overide the stat it can and the boiler quitens down. Any ideas what would cause it fire without any call for heat?

 

[ecowarm]

Frost stat??

 

[Dannypipe]

Faulty motorised valve, wiring centre (if they have one of those honeywell wiring centres where the works done for you) faulty stat (unlikely) faulty PCB on boiler.

OR -

As I had on a Firebird once.... Someone has left the 'TEST' switch on the boiler. You know the switch on the boiler itself.

I got called to a similar problem once. The boiler had been serviced by another engineer who they didn't want back as they didn't trust him!! He had left said switch on and the boiler SL was always on. Took me a while to pick it up as I was tracing it back from the wiring centre and M/V's.

Basically boiler was coming in and out on it's own stat.

Or could be frost stat as mentioned.