Glowworm boiler problems

[borgfan]

House is fitted with a glowworm fuelsaver 50br ( ~ 14 years old) which has been causing some problems over the last few months. First the boiler would not stay lit, so I had it serviced - engineer said it was sooted up so he cleaned it and replaced the thermocouple. Then a few weeks later the pilot light would not stay lit so thermocouple was replaced again - no problems for a few weeks. Then boiler started to cut out a few minutes after firing up. Heating engineer replaced the overheat cutout and again no problems for about 2 weeks. Now seeing the same problem. Pilot light stays lit ok, switch on boiler thermostat, it fires up and then after a couple of minutes cuts out. The pump is spinning ( though its a bit noisy). Now the engineer I have been using is saying that he thinks I need to replace the boiler - but can't tell me what is broken. What should I be looking at, any ideas gratefully received.

Gerard

 

[ChrisR]

Pump is suspect and would cause the sort of problems you have and you'd need one anyway if you changed the boiler and they cost a tenner .
Change the pump!

 

[PEDANTICVINDICTIVEMAN]

Why do you need to change the pump if you change a boiler and since when and where can you buy a pump for a tenner ?

 

[ChrisR]

Would you install a new boiler and leave a noisy pump?

Sorry, retail price on a pump is 20odd upwards. still not much if it fixes the man's problems.
I don't pay rrp for anything much...

 

[Paulie]

I've had some fun and games with a Glowworm boiler - maybe this could be what's happening to yours. This one was cutting out after a couple of minutes due to a faulty thermistor on the fan motor. When the fan got warm, the thermistor, which is fitted on the fan windings, would trip. The fan would then stop, causing the air pressure switch to cut the gas supply. When it cooled sufficiently, the fan would start up and the cycle was repeated. It tooks several visits by a plumber who fitted a new stat & cutout before I had a look myself and got a new fan.