Hi All,
First post.
We have had new radiators fitted which did not appear to be getting as hot as expected. So a new thermostat was fitted to the boiler. Boiler worked correctly for ~ 13 hours and then started to buzz. Buzz was diagnosed as faulty gas valve. The gas valve has been replaced and for the first couple of hours boiler appeared to work perfectly. However shortly afterwards, we were back to the situation where after a period of time the coil on the gas valve buzzes.
The boiler is a Glow Worm Fuelsaver MK II model B (GC Number 41 315 95). The original gas valve has been replaced with a SIT NOVA 820 24V (SIT 0820026).
It seems as if the bolier goes up to the temperature set on the thermostat, the thermostat then turns off the coil. When the thermostat then trys to turn the coil back on the coil starts to buzz and the boiler does not start. If the thermostat is turned off and left for a period of time the thermostat can be turned back on and the boiler starts without the buzzing noise.
Our heating engineer has fitted the old thermostat back into the boiler but the coil still buzzes after a short period of time. Initially when the old thermostat was fitted, the buzzing would start then immediately stop and the boiler would recover and continue to operate. However this only
lasted about an hour and the buzzing now results in the boiler cutting out completely. The engineer and myself have made a number of measurements on the bolier by following the fault finding guide and have observed the following:
When coil buzzes voltage across the coil is 13V - 17 V
When coil is not buzzing voltage across the coil is ~22 V
At all times without coil attached and thermostat on voltage across is ~37 V
At all times with thermostat off voltage across is 0 V
The above can be reproduced with the original thermostat or the new thermostat connected to the boiler. It seems that the coil starts to buzz sooner with the old thermostat fitted.
The fault finding guide in the servicing instructions state that with the measurements we have the coil has failed! Is it feasible that we have two coils that seem to fail when they "get hot"? I was wondering if any one on this board has had an experience of this type of problem?
Thanks,
Graham.
First post.
We have had new radiators fitted which did not appear to be getting as hot as expected. So a new thermostat was fitted to the boiler. Boiler worked correctly for ~ 13 hours and then started to buzz. Buzz was diagnosed as faulty gas valve. The gas valve has been replaced and for the first couple of hours boiler appeared to work perfectly. However shortly afterwards, we were back to the situation where after a period of time the coil on the gas valve buzzes.
The boiler is a Glow Worm Fuelsaver MK II model B (GC Number 41 315 95). The original gas valve has been replaced with a SIT NOVA 820 24V (SIT 0820026).
It seems as if the bolier goes up to the temperature set on the thermostat, the thermostat then turns off the coil. When the thermostat then trys to turn the coil back on the coil starts to buzz and the boiler does not start. If the thermostat is turned off and left for a period of time the thermostat can be turned back on and the boiler starts without the buzzing noise.
Our heating engineer has fitted the old thermostat back into the boiler but the coil still buzzes after a short period of time. Initially when the old thermostat was fitted, the buzzing would start then immediately stop and the boiler would recover and continue to operate. However this only
lasted about an hour and the buzzing now results in the boiler cutting out completely. The engineer and myself have made a number of measurements on the bolier by following the fault finding guide and have observed the following:
When coil buzzes voltage across the coil is 13V - 17 V
When coil is not buzzing voltage across the coil is ~22 V
At all times without coil attached and thermostat on voltage across is ~37 V
At all times with thermostat off voltage across is 0 V
The above can be reproduced with the original thermostat or the new thermostat connected to the boiler. It seems that the coil starts to buzz sooner with the old thermostat fitted.
The fault finding guide in the servicing instructions state that with the measurements we have the coil has failed! Is it feasible that we have two coils that seem to fail when they "get hot"? I was wondering if any one on this board has had an experience of this type of problem?
Thanks,
Graham.
