Vaillant Ecotec F61 Fault

The valves on these will be modulating gas valves - so typically a stepper motor that driven driven rather than the older style solenoid open/close one. So probably less likely to get completely stuck.

Are there any other indications that the boiler is having difficulty electronics wise? Like fluctuation of the displayed temperature on the front panel? That can indicate a problem on the PSU section of the main board. If so a likely culprit are some of the electrolytic caps on the PCB. There are a couple that are on the input of a regulator that in turn powers the MCU.

If it is caps you would be more likely to see faults intermittently, and usually when the boiler / room it is in is cold.

(when mine failed last year (a more total complete power off during startup), I suspect the main reservoir cap on the PSU was the issue. I could do a very short term fix on it just by warming up that area of the PCB with a hairdrier. (cold caps have lower capacitance than warm ones)).

If in the last few days it could just be the software getting lost with intermittent mains electricity. I'm aware in certain areas of the country people have been noticing lights flashing off and on. If the mains drops out from your boiler for fractions of a second it may result in an erroneous error code(s). Switching the boiler off for around 60 seconds should reset it on switch on.

Not noticed any fluctuations on the display.

It was 9C. I switched it on remotely when I realised how cold it had got. It fired for maybe a minute or two and then shut down with the F61 code.

Thanks for that - I think I'll let it fail again and see. 'Refurbished' boards are only £30ish exchange so I'll give that a whirl if it comes to it.

Ah interesting - I was away when the fault happened so I'm not sure what local conditions were like.

Geoff (former poster here) does most PCBs on a recon exchange basis - you buy one, fit it and send them your broken one.

Excellent, thanks - but more expensive but likely more than just an untested 'pull'. They're not doing exchange for my board though, which is a shame.

I'll take a look - seen videos. But my soldering is pitiful.