Glow Worm econ 40:burner run for 5mins ?

[sean_the_cat]

After the enevitable start up after the summer my system has the following problem:-

we have an old style pumped system with hot water tank. A local plumber looked at the fault and just said it a wiring fault and left. The system had run okay for 6/8 years with no issues so i doubted the advice but then set about tracing the system.

I've swapped the y valve and replaced the pump.

The the pump runs okay on the cyl stat and the burner fires from cold. but only runs for about 5 mins. ive checked the over heat sensor on the outlet and the cct is made. The solenoid is energised and the thermostat in the boiler seems to switch okay


i now suspect the gas valve which must have some kind of flow sensor


I assume that fitting a new gas valve, is a Corgi fitted product just looking for some intelligent comments for a vaguely technical DIYer

i do have the orginal service manual with the Gas Council parts lists

 

[geoff@cetltd]

Maybe some other blockage restricting the flow

Flow sensor in the gas valve ?

I doooooont think so

 

[sean_the_cat]

thanks for the comment


okay but the hot water gets upstatis to the hw tank it just shuts down after 5 mins. I suspected the flow when i changed the pump. How do i check water flow at the boiler? the pipes are stashed away is the flow sensor on the valve or in the boiler housing ?

 

[sean_the_cat]

Sorry raden just re-read your comment

My assumption was that ther was some kind of flow sensor

the logic was this :-

Pump runing

thermostat made, solenoid energised

thermal cut out Made (fail safe I assume)

just looking a reason for the burner to fire initially and then shut down

 

[sean_the_cat]

Problem sorted:

Got local man: R+B plumbing and heating put a new valve and all is rosy. Still not sure as to why the origianl valve would only run for 5 mins (solenoid stil energised and not overheating) but everthing is toastie now.