Glowworm fuelsaver- RGI has given up

[halton1957]

I'm not familiar with this forum, please tell me how to "Watch" this thread.

 

[halton1957]

I'm not familiar with this forum, please tell me how to "Watch" this thread.

OK found it now.

 

[halton1957]

Feel the flow pipe from the boiler. When the boiler cuts off does it cool quickly?

No, Pipes and pump remain hot. Is this a sign pump is not pumping? It is definitely spinning though.

 

[TCCHeating]

It's possible. I have seen it before when the pump apperars to be spinning when you take the front cap off. But the impeller shaft has sheared so the motor is not actually spinning the impellor.

 

[halton1957]

Power leaving board to fan so next step would be is power being received at fan if so and fan not spinning then its the fan.

Power is definitely at the fan till boiler shuts down, evidence is the plume of steam at the exhaust. Is the any kind of cutout built into the fan?

 

[halton1957]

It's possible. I have seen it before when the pump apperars to be spinning when you take the front cap off. But the impeller shaft has sheared so the motor is not actually spinning the impellor.

Thanks, I've experienced similar in a previous life. But I guess there's no easy check for that?

 

[TCCHeating]

You would have to isolate the pump and remove the head ( generally 4 allen screws. You might need to drain the system. If the pump does have isolation valves they prob wont turn off fully, and if they are screwdriver type dont touch them with a bargepole! Good luck

 

[halton1957]

It's possible. I have seen it before when the pump apperars to be spinning when you take the front cap off. But the impeller shaft has sheared so the motor is not actually spinning the impellor.

Forgive my lack of knowledge but if the pump wasn't doing it's job I guess the shutdown would be caused by the overheat cut out. On this boiler the o/h cutout is manual reset, and it isn't tripping.

 

[TCCHeating]

Depends on what the boiler thermostat is set at. Is it at max? Also pump may be getting rid of just enough heat not to trip overheat stat. If boiler stat is at max and pump is totally stopped then you should hear a banging and overheat stat should trip.

 

[halton1957]

Depends on what the boiler thermostat is set at. Is it at max? Also pump may be getting rid of just enough heat not to trip overheat stat. If boiler stat is at max and pump is totally stopped then you should hear a banging and overheat stat should trip.

Yes boiler stat is at max. No banging, no overheat trip.
Just dashed outside after a shutdown, fan is definitely running on there was steam coming out with some force.

 

[halton1957]

Deleted as I realised I was grasping at straws.

 

[halton1957]

I've let the boiler continue to do it's own thing for a couple of hours and it has heated the rads to a medium temp I can hold my hand on but hot enough to turn the gas fire off. It's still cycling on and off.

 

[halton1957]

Depends on what the boiler thermostat is set at. Is it at max? Also pump may be getting rid of just enough heat not to trip overheat stat. If boiler stat is at max and pump is totally stopped then you should hear a banging and overheat stat should trip.

Yes boiler stat is at max. No banging, no overheat trip.
Just dashed outside after a shutdown, fan is definitely running on there was steam coming out with some force.

Not so sure the fan is running on now need to check again in the morning. Thanks for all help so far.

 

[TCCHeating]

You have a circulation problem for sure. Prob pump only partially working as said before, could be other probs as well. (Blockages or air in system etc etc..... I would say that there is Prob nothing wrong with the boiler at all

 

[dcawkwell]

Sounds like the boiler has just enough water flow to allow a little circulation allowing the boiler to heat up quickly cool down quickly.

I would drain the system down. Check operation of pump perhaps flush the system out with the mains cold. Then try it again.

Very little to go wrong in the boiler.