Glow Worm 65f Fuelsaver

[Kingsteele]

Hi all,

I've used this site so many times but never had the need to post before (I've always got the answer!)

I'm desperate for someone to wrap their grey matter around my problem with the above boiler. It's old I know, and I know I should probably get rid but financial restraints mean I need to try and get it working.

It's running a 3 bed house radiators and a water tank for hot water. I've noticed since Turing the heating back on that the radiators were only getting tepid at best and that the hot water went cooler at the same time.

I thought it was a thermostat problem as the boiler will fire up and stay lot for about 30 seconds before going off. If I have it just on hot water it does heat the water ok but with sporadic 30 second bursts from the boiler.

So I changed the overheat termostat and the main thermostat but still have the same problem.

I've checked the valves open to let the water through the rads and that the pump is running. The water leaving the boiler is hot and the water returning from the rads is cool, however it will only mange the 30 seconds before going off again.

Any ideas will be massively appreciated.

Thanks

Brett

 

[ollski]

Air lock in the pipes?, should be a bleed point in the airing cupboard somewhere.

 

[Armo74]

Probably a circulation problem due to a build up of sludge.
When you bleed the rads does black water come out?
When was the system last cleaned?
Do you have to constantly bleed your rads?

 

[jeff the gasman]

Edit

 

[bazdaman]

Are you sure pump is working correctly?

 

[Kingsteele]

Thanks everyone. Yes the pump is working fine and when turned up to 3 is really getting the flow going.

Would an air lock cause the boiler to stop? It's not overheating at any point as I can hold onto the feed from the boiler when running ch only and the return is cold. When running the hw circuit alone the feed and return are mega hot and the boiler. That seems to indicate that the pump and valves are operating as they should ?

It will just keep circulating cold water around the ch system without firing back up again for about half an hour for another 30 sec burst.

As an update I've also now had the pcb reconditioned. ...

 

[Kingsteele]

Thanks for all the replies. It's sorted now so I wanted to put the solution up for anyone with similar problems. It was the fan. I put a volt meter across it when it was running and it showed 230v going to it. When it stopped as the boiler shut down it was still being sent 230v from the pcb so should in theory have still be running, also when the hw had reached temp through the 30 second bursts it was being sent 0 volts as it had turned off on the thermostat.

I then ran it from mains bypassing the pcb and it would stop after about a minute, be off for about ten minutes and the start again.

So recon fan fitted and it's working like a dream, albeit with a recon pcb, new thermostat, new overheat thermostat and a good service.....