Ravenheat RSF 100ET (Intermittent) Flame Failure Problem

[MarkHarwood]

Flame failure light comes on. So I reset, turn off the power, turn back on.

1) Call for heat, pump runs, fan doesn't, FF light comes on after a few seconds.

2) DON'T call for heat, FF light still comes on after a few seconds.


This problem started a few months ago, so I took it all to pieces and put it back together again and it worked. Probably nothing to do with taking it to pieces though.

It was OK until last week when the same thing happened again. It had had a problem with the electrode cables shorting (under guarantee) and the engineer put on a bit of extra insulation where they were close so I taped them up with electrical tape (!) from top to bottom. Reassembled everything and it worked!

Same thing happened again. Disassembled and reassembled the case, moved the cables about a bit and again it worked! Twice.

Now, I'm not convinced the disassembling is actually doing any good but four times now it seems to have temporarily resolved the problem whereas simply turning the power off and resetting hasn't.

Why is the flame failure light coming on even before the boiler has called for heat? Does any of this make any sense to anyone?

 

[gas4you]

The first thing I would do would be call Ravenheat back in as it is still under warranty.

 

[MarkHarwood]

No, it's not still under warranty, unfortunately, nearly two years old.

My Corgi plumber reckons he can't fix an intermittent fault without guessing and I'm a bit worried he might go straight for the PC Board and if that doesn't work decide "Oh it must have two faults then". Or three even.

 

[gas4you]

Check the ch thermistor and/or the overheat stat.

Your engineer should be able to test these.

The ch thermistor doubles up as the overheat sensor and is notorious for faulting on these.

They are about £15 to buy.

 

[MarkHarwood]

Thank you. It fired up tonight so all is well at the moment though I don't expect it to last.

The engineer can't come until Saturday and may well decide he's got more urgent jobs if it continues to work (he's busy!) but if it doesn't the prospect of five freezing kids is not a happy one!

 

[SortedPlumbing]

You might think this is a silly Q -

When it fails to light up what is the weather like outside-?
Any chance that it has been raining?
What is your Flue like?

First thing i would be looking at is blocked flue venturi(Common on these to be blocked by rain! Especially on vertical flues)

If not that i would be thinking APS.

 

[MarkHarwood]

No, not a silly question at all, I had wondered about the flue. It goes straight out through the wall and projects about 4" into a well ventilated (windy) passage.

I can't see any correlation to rainfall, I don't think there was much over the last ten days (when it's been misbehaving) and it has certainly worked OK during recent periods of heavy rain.

Air Pressure Switch? I wondered about that too.


I'd be happier if it were a permanent rather than an intermittent fault, I have a horrible sinking feeling that I'm going to pay someone to 'fix' it and then in the deepest darkest coldest depths of a winter holiday period or Friday afternoon it's going to fail again. I keep thinking it might be prudent to get some spares in, just in case! But which spares?