Boiler only fires up intermittently

[Bonus77]

Hi,

I have a problem with my boiler, and im not sure where to start.

I had a problem a month or so ago, and managed to fix it by replacing the programmer, but now i have a new problem.

The problem seems to be, that the boiler doesnt fire up when it should do. If I run the system on constant, it will fire up for 5 mins then shut itself off. I think its something to do with the water temperature, because if I turn the temp of the boiler up to max, it fires up.

The pump seems to be whirring away fine, it gets hot to touch, but dont think thats the prob.

Where should I start?

Its a potterton Flamingo boiler, with a honeywell timer, motorised control valve... if theres anything else i should list let me know.

 

[John506]

how long since your central heating system was serviced, such as drained down, flushed out, chemicals have or haven't been used?

 

[gas4you]

If the pump is getting hot to touch without the boiler firing up properly, I would suspect either a faulty pump or perhaps the heating system is not properly full of water.

See FAQ's on checking a pump AND cold feed blockages etc.

 

[namsag]

Following on from G4Y reply check header tank atually has water in it,the ball valve may have stuck

 

[Bonus77]

how long since your central heating system was serviced, such as drained down, flushed out, chemicals have or haven't been used?

I drained the system down a few weeks back because of a leakage. Managed to get everything back up and running for around a month before the probs occured.
I didnt use chemicals, just a simple flush.

 

[Bonus77]

Following on from G4Y reply check header tank atually has water in it,the ball valve may have stuck

Header tank is full.

The pump only gets hot when the boiler doesnt fire up, when its running, it seems okay. Could be a blockage I guess, will have a read up the FAQ's but if anyone else has any better ideas, let me know.

 

[Bonus77]

Just to add, when the boiler does fire up, popping sounds can be heard, and even a slight hissing. Its not very loud at first, but gets slightly louder before the boiler fires down.

Is that kettling?

 

[bengasman]

Flamingo = old open vent = full of carp. never misses

 

[Bonus77]

Flamingo = old open vent = full of carp. never misses

Cheers

Best way to remove said carp? Fernox? Chemical flush?

 

[bengasman]

My favorites are HYPERFLUX and FERNOX F3.
Tip a bottle in the headertank, make sure it is the heating and not the bath-tank, and let it run for 4 weeks

 

[Bonus77]

My favorites are HYPERFLUX and FERNOX F3.
Tip a bottle in the headertank, make sure it is the heating and not the bath-tank, and let it run for 4 weeks

Cheers, will try that.

Just out of curiosity, is there a quicker way of doing this? The boiler doesnt fire up long enough to heat the rads and not sure i could go that long without heating or hot water.