Yesterday morning we discovered we had no hot water because the boiler had failed to come on for its programmed morning cycle. Over-riding the controller has no effect. The fan relay operates, but the pilot makes no attempt to light. There are no other signs or sounds of life - just the fan running. The boiler is a Netaheat 16-22 Mk II F
I called my reliable CorgiMan but got no response. Eventually we did get someone else to inspect it, but he was not entirely helpful. Said it was an old unit (true), parts were no longer made and we'd be better off replacing it (which he could do for us of course). I wasn't comfortable with his apparently superficial diagnosis, so said I'd think about it. Shortly afterwards, my usual, reliable heating engineer returned my earlier phone call (from his holiday destination!). He had serviced the boiler last year and was adamant that parts were still available and we shouldn't do anything rash.
We could wait another 10 days for him to return, since we have an immersion heater to provide hot water, but meanwhile I would like to know if there is any diagnosis I can be getting on with. I am an electrical engineer and it seems like the problem is likely to be a controls one, rather than a plumbing issue.
I have the lower front panel off, and am equipped with a wiring diagram. Electrically, this is a fairly simple piece of kit. However, what I do not know for sure is how the electrics are supposed to function with the various plumbing components that I can see: gas valve, pressure switch, etc, and in particular what conditions must be met for the pilot to light.
I don't want to tackle anything that disturbs the integrity of the gas system. I just want to conduct a function check. What would be the recommended sequence of diagnostic tests to pin down the offending component ?
I called my reliable CorgiMan but got no response. Eventually we did get someone else to inspect it, but he was not entirely helpful. Said it was an old unit (true), parts were no longer made and we'd be better off replacing it (which he could do for us of course). I wasn't comfortable with his apparently superficial diagnosis, so said I'd think about it. Shortly afterwards, my usual, reliable heating engineer returned my earlier phone call (from his holiday destination!). He had serviced the boiler last year and was adamant that parts were still available and we shouldn't do anything rash.
We could wait another 10 days for him to return, since we have an immersion heater to provide hot water, but meanwhile I would like to know if there is any diagnosis I can be getting on with. I am an electrical engineer and it seems like the problem is likely to be a controls one, rather than a plumbing issue.
I have the lower front panel off, and am equipped with a wiring diagram. Electrically, this is a fairly simple piece of kit. However, what I do not know for sure is how the electrics are supposed to function with the various plumbing components that I can see: gas valve, pressure switch, etc, and in particular what conditions must be met for the pilot to light.
I don't want to tackle anything that disturbs the integrity of the gas system. I just want to conduct a function check. What would be the recommended sequence of diagnostic tests to pin down the offending component ?