Glow worm boiler tripping out

[carytb]

We have a Glow-worm 120FF and recently it has started tripping out. Waiting a while and pressing the reset/trip button sorts it out.
What happens is that after the Central heating has been on for a while and we turn down the radiator thermostat on the radiator nearest the boiler it the system starts to bang and crash through the pipes - similar to water hammer effect and then it trips out. I was wondering if it was the hot water returning back to the boiler without cooling having not been through the raditors. If so would turning the therostsat on the boier down slightly help. For reasons unknown to me we do not have a central room theromstat on the system only therostatic valves on the radiators.
Cheers

 

[Jonnie]

Check ballvalve in central heating tank is not stuck and therefore not filling the central heating up as it sounds like the whole system is short of water and causing the boiler to over heat and trip off

 

[John506]

Has inhibitor been introduced into your system?

How long ago was it flushed out?

Your heat exchanger could be scaled up or full of dirt, and it can cause insulation in the heat exchanger which will cause it to overheat before the water is up to temp and trip out.

Why would the water not be flowing through the radiators? It wouldn't cause the boiler to trip out.

 

[carytb]

Check ballvalve in central heating tank is not stuck and therefore not filling the central heating up as it sounds like the whole system is short of water and causing the boiler to over heat and trip off

Thanks I'll pop up into the attic and check this

 

[carytb]

Has inhibitor been introduced into your system?

How long ago was it flushed out?

Your heat exchanger could be scaled up or full of dirt, and it can cause insulation in the heat exchanger which will cause it to overheat before the water is up to temp and trip out.

Why would the water not be flowing through the radiators? It wouldn't cause the boiler to trip out.

I've no idea about the inhibitor and the system has not been flushed out in the last few years. My reasoning aboutthe water not flowing through the radiators was that if the house was warm enough then most of the therostatic valves on the radiators would be shut then when the last one shuts the water will flow through the sytem quickly as the valves are shut and get back to the boiler a lot hotter than normal resulting in it overheating. As you can probably tell I am not a central heating engineer!

 

[Jonnie]

is there thermostatic rad valves on all radiators? if so there should be an automatic bypass fitted on the system some where, it could be that all the thermostatic radiators are shut down not allowing the pump to get rid of the heat in the boiler.