Intermittent Boiler- Short firing

[JoeSoda]

Boiler type: Thorn EMI- Apollo
Problem: The temperature of the house is below the temperature set by the thermostat- so, naturally, the boiler comes on. However; the boiler only fires for ~5 seconds, turns off, waits for ~1min, and then fires up again. This process is repeated until the temperature on the thermostat is reached- which, because of the intermittent firing, takes rather a long time.
Does anybody know why this may be occurring?
Thanks.

 

[bengasman]

bit more info would not go amiss

 

[JoeSoda]

Yes, sorry. I don't know much about plumbing. What sort of info do you need to know?

 

[bengasman]

anything done to the system?
anything happened ?
timer settings altered?
pump running?
radiators all evenly warm?
any info that could be related really

 

[gavinda]

aps? you need someone qualidied to open the boiler.

 

[JoeSoda]

I have been in the house 1 year, and I haven’t done anything to the system.

The timer is set correctly (the problem still persists when the timer is set to ‘continuous’).

All the radiators get hot, but because of the intermittent firing I don’t think they are getting as hot as they could be.

There is a pump (Grundfos UPS 15-50X18). It sounds like it is working, but I’m not really sure.

Thanks

 

[twgas]

is it the fanned flue model, if so I suspect the inner flue rotted causing contaminated air be sucked in and putting flames out.

 

[JoeSoda]

I don’t know which model it is? It doesn’t say fanned flue on it. How will I know?

 

[bengasman]

if you so much as suspect a possible flu problem, you should get an RGI in. pronto

 

[twgas]

look at the bit that goes through the wall, if it's a 10cm round one it's fanned, if its 30cm square it's not. Also if there is not a pilot liight (in the little window) it's a fan flue.

 

[JoeSoda]

I can't see the pipe that goes in to the wall. But there is a pilot light. It remains on the whole time.

 

[twgas]

thats my theory out the window then.

 

[gavinda]

is this the one with the plastic aps on the fan module guys? these melt and the cork gasket shrinks on the aps. that would give this result. you need someone qualified to break the seal