ravenheat rsf820/20 combi

[creader]

i have a ravenheat rsf820/20 about 8yrs old recently the boiler cut out with some very strange clanging noises,when i tried to relight it, boiler fired up even though no hw or heating was on ,the pressure built up really quick to the point where it cut out again.any ideas is it repairable or has thing had its day? creader

 

[werewolf]

poosible gas valve gone faulty and firing up even though no electric supply.Boiler not worth repairing, throw in bin and get good vaillant/worc boiler fitted.

 

[gas4you]

Blocked heat exchanger?, faulty pump? Banging usually no circulation

 

[werewolf]

If the electrics to boiler are OFF then gas valve must be jiggered .see previous post.

 

[gas4you]

Have I missed something? Where does op say electrics are off

 

[corgiman]

poosible gas valve gone faulty and firing up even though no electric supply.Boiler not worth repairing, throw in bin and get good vaillant/worc boiler fitted.

how does that work then??

surely in the very unlikley event of this happening (no switch live and boiler fires up) you are looking at the PCB relay

I really cannot believe this could ever happen, more like a sticky flow switch

PS this is a combi ravenshit aint it?

 

[sambotc]

Agree DHW flow switch possibly stuck seem's the likely culprit..

 

[Agile]

The diverter valve is probably jammed and creating a phantom demand for DHW.

Could also be caused by water leaking onto the switches.

Tony

 

[ChrisR]

Maybe one switch is stuck on brnging boiler on without the pump. Otherwise sounds pcb relay ish

 

[pannierstan]

I agree with Corgiman.

probably find water is peeing from DHW connections on h/ex and then dripping onto the board.

Either that or the relay is stuffed and has now turned into a blob of molten plastic also stuffing the board and the connector behind it.

I have a board and a set of new connector plugs just for this occurence which has happened many times.

Stan

 

[Agile]

I also have a spare pcb which from memory used a Finder relay which never fails.

Neven have I ever found a PCB failing on this model. Everything else and particularly the diverter valve though.

Tony

 

[Slugbabydotcom]

If anyone is taking bets my money is on the flow switch stuck in the on position as well. I have changed a few pcbs but never come across the relay sticking on so far.