Boiler intermittently fails to light

Bob Smith (UK) · 2004-10-26T11:22:32+00:00

It's a Ravenheat RSF82E. It's a fanned combi, the kind that lights everytime there is a demand for heat (ie no pilot). I have a manual / websitefor the manual if that would help.About 1 in 50 times, it fails to light when the CH water cools off a bit.It is part way through the lighting cycle that it fails, the big "clunk"that the gas valve makes. I am not sure what is causing it though, and have3 theories.1) The gas valve is sticky (although I hear no failed mini "clunk") andfails 1 in 50 times.2) The fan is faulty, and does not draw enough air for the boiler to thinkit is safe to light (assuming the boiler is that smart). The fan does soundscraping / rattly when it slows down. A gust of wind could shift aborderline fan to a "not fast enough" state.3) The sensor that detects the fan is working is faulty / blocked with fluff(assuming it is that smart).Is there anything else that could cause this? Any quick and cheap (eg tapgas valve with hammer, hoover sensor out) fixes that cure common problems?The boiler would work fine if it had a "retry" built into the lightupsequence, but as it is, I keep finding the boiler with a light lit up,merrily blowing cold air past the CH water (the fan comes on before the gas)chilling it. Turning the thermostat down then up, or switching CH off thenon restarts the lightup sequence. The proper "reset" botton does nothing(not lack of flow/boiling water problem).Extra info/hint: Sometimes if I am there when it fails to light, me doingthe the on/off thing causes it to try again, but it will fail to light 2 or3 times in a row, suggesting it is some condition causing the failure thatgoes within 30 seconds.Any ideas / suggestions?ThanksBob

Oct 26, 2004 26 Replies

Rate this thread:

raden 21 years ago

In message , "Bob Smith (UK)" writes

Relay on the pcb ...

Vote

raden 21 years ago

In message , raden writes

formatting link

btw

it's what I do

Vote

Bob Smith (UK) 21 years ago

Are we talking dry / bad solder joint, or worn out mechanically?

Bob

Vote

raden 21 years ago

In message , "Bob Smith (UK)" writes

Burned out

Vote

John 21 years ago

Anything from a blackened contact to a large piece of printed circuit board charred beyond recognition

Vote

Bob Smith (UK) 21 years ago

I bought a new air pressure switch, and that didn't work.

Been reading other threads, and someone mentioned gas pressure decreasing due to a blockage in a filter in the meter.

This sounds promising, since the problem is getting worse over time, AND I have a problem with my gas grill. I am sure the flames used to be bigger on the grill, but it has also been getting worse, making popping noises, and after a few months, going out. I have had the burner out and poked pipe cleaners in, and have also checked the venturis for fluff, with no effect. Gonna give Transco a call today.

Bob

Vote

Bob Smith (UK) 21 years ago

Argh!!! That's not it. The pressure is fine.

Bob

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required