Britony "Combi 80" - symptoms restated

[Jim D]

Here is exactly what I'm experienceing with my Britony 80 combi boiler.

CH problems: Boiler is not firing up very often, and when it does, it switches itself off after a few seconds - or after 40 about seconds if I'm lucky. I have disconnected the programmable thermostat/timer to eliminate that from the equasion. I bridged the contacts where its 2 terminals were connected to the boiler's cirquit board, so that the boiler is now conrolled only by the TRVs on the rads, a couple of which are fully open.

DHW problems: Turning on a hot tap produces plenty flow, but the water is cold. The boiler fires up for as long as the tap is left on, but the secondary heat exchanger stays stone cold. The first sign of trouble was several hours ago when the tapwater only got luke warm. Now it is stone cold.

The system was working satisfactorily a few days ago. The first sign of trouble was when the CH system burner didn't fire up as often as I think it should have.

Thanks for any suggestions,

Jim D

[Jim D]

PS This morning (the morning after the above post), the problem with the CH remains the same. and the rads are only slightly warm.

The DHW is now fine - lots of hot water from taps.

A friend suggested that it sounds like a diverter valve problem. Anyone agree?

Thanks,

Jim D

[Jim D]

PPS... Later in the day, the faults disappeared! The CH and the DHW are both faultless now! I just hope it stays that way...

I'd still be interested to hear any diagnosis of what was going on though...

Thanks,

Jim D

[Ed Sirett]

Diverter valve trouble by the sounds of it. How does the valve move in this model? What is the state (of cleanliness) of the primary circuit?

[Jim D]

I don't know. I know that the technical bloke from the boiler's distribotors said once that they "never go wrong"... "because they are underwater"... or something like that.

What is the primary circuit?

I have just desludged the system, though I do not know how successful the operation was.

Thanks,

Jim D

[Ed Sirett]

The water in the boiler and radiators. See glossary in BoilerChoice FAQ.

[Jim D]

Just for the record, it turned out that there were two faults happenning simultaneously:

(1) there was a fleck of debris in the entrance of the narrow vent pipe that leads from the flue to the fan sensor.

(2) The CH thermistor was faulty.

All is OK now.

Jim D