Ravenheat 820/20 won't fire up

[Topanga]

The pilot light is on but there is no hot water/heating. When the hot water/heating are turned on I can hear something switching and the fan (I think) runs but nothing else happens. Any ideas please?

 

[gas4you]

If the fan is definately spinning then I would first suspect the air pressure switch.

 

[Topanga]

Thanks for the reply Dave, I took the cover off to get to the switch but the pilot light has now gone out and won't stay lit. Would a faulty pressure switch do that?

 

[gas4you]

Sounds like the thermocouple gone. I can't remember if this is in series with the overheat on this one though.

Have you tried looking foe an overheat reset button. Usually reddish brown if you have one.