British Gas 330+ kettling?

[sikboy]

hey guys, stuck with a mates boiler (british gas 300+ condensing system boiler, think its a rebadged glow worm hxi?)

boiler fires up, then drops to low flame and runs for about an hour heating the water and heating.

after an hour it starts banging on like the water inside it is boiling for a couple minuets then cuts out?

Pump is working fine, 2port valve is working fine, no air or muck in the system.

Boiler is 3 years old, fitted by british gas with mangna clean, inhibitor etc.

any advice would be greatly appreciated! cheers

 

[diamondgas]

Any 'F' faults showing? Thermister giving correct readings? System bi-pass set up correctly? Correct low fire rate? You could maybe have a faulty 2 port that's shutting off but the boiler is still getting it's live ... ! A bit more info could help but there's a few things to check out

 

[AllyBongo]

Fitted a load of these for BG, they always seem to be troublesome for air unless piped well. I take it it's an open vent, could of drawn air in. Vent should come right off the boiler, if not stick some aav's in

 

[sikboy]

hey guys, sorry for the late reply iv been away! no F faults, just runs for an hour then starts making the noise and modulates between 39-41?! was over tonight, as soon as it started making the noise truned it off for about 3 hours till system had cooled down then turned it back on again and was instantly making the noise and rads wernt getting hot? any ideas?

 

[GasmanxxxR1]

Blocked heat exchanger???

Is the system dirty?, these boilers are sensitive to sludge, restrictions and small air locks. it could also be the flow and return thermistors as they often need replacing

 

[moogwai]

Sounds like you have a blockage somewhere and the water isn't circulating. Try draining down and see if the water leaves the f and e tank.....if it don't you'll have an idea where to look first. Quite common to have a blockage around the neutral point.

Sent from my Desire HD using Tapatalk

 

[GasmanxxxR1]

Remember a 'blockage' can be made of air aswell, it all has the same effect = restricted flow

what condition is the pump in?

 

[sikboy]

system seems to be clean as a whistle, water running clear. had it drained down a couple times and refilled bleeding out all the air. cant work out why would make the noise instantly and not heat up after being left to cool for 3 hours tho? pump seems to be working fine, all the rads are getting hot nice n fast.

 

[GasmanxxxR1]

Is there an auto bypass?

Where abouts in the country are you?

 

[GasmanxxxR1]

Whats the boiler thermostat set to?

 

[sikboy]

newcastle mate, stat is set to 60. lad told me yesterday he had wired a tv into the system wiring?!?!?! apparently that was back in november and its been working fine since. heating hadnt been on since about march and when they tried it last month it started the noise

 

[sikboy]

there was no bypass in the system so i stuck 1 in between the pump and 2port

 

[GasmanxxxR1]

If it is a s plan system and had no auto bypass, this could have been where the troubl started. As to cutting on to low rate.... The thermostat on the boiler should be set to about 75, just use the + and - buttons on the front of the boiler. have you commissoned the auto bypass correctly?
Try bleeding the system and the pump

These boilers tend to behave like this when they are first commissioned and it can take ages (hours) to get every last bit of air out of the system