A carpenter on a job i'm doing at the moment came to me the other day and said his boiler pilot light kept going out. he told me he'd had the gas valve replaced and the thermocouple yet after 20 minutes or so, it would cut out. It was an old open flued boiler (the kind that kill people if not correctly looked after) and he was baffled as to why it wouldn't work. I asked him a few questions and soon stumbled upon the answer. Where the ventilation for his boiler used to terminate on the outside wall, he'd built an extension and not installed a vent in the new room he'd created. The result of this is the appliance was starved of oxygen and couldn't burn efficiently and correctly. This leads to incomplete combustion which in turn can cause carbon monoxide to spill back into the property, instead of going up the flue. This is what was happening in his case. They were suffering from headaches and drowsiness.
I advised him to get a vent installed immediately but in the mean time, to open a window in that room and leave it open. If he'd have told me where he lived i'd have gone round and cut off his gas supply!
i saw him today and he could't thank me enough. Turns out that the guy that replaced the parts in his boiler was just a mate, who wasn't qualified and only charged him £50 to do the work and £125 in parts. There was nothing wrong with the boiler. His mate who he thought was doing him a favour nearly killed him and his family. He left his catflap open over the weekend until he could get a proper vent installed and has since stopped feeling drowsy and his boiler has worked fine since.
If your boiler breaks down peeps, no matter how "handy" you think you or your mate are, for the sake of a few extra pounds it just isn't worth it. Always use a qualified engineer. If your boiler is spilling carbon monoxide, you won't know about it. It doesn't smell like gas does. If the boiler is spilling badly enough, you'll go to bed and you won't wake up. simple as that.
Also if you have an open flued boiler, make sure you have a carbon monoxide detector!!!!!!!!!!!!
