Glo worm pilot

[bobb]

I've got a glowworm fuelsaver MkII - about 17 years old.

The pilot went out so I tried to relight it as per the instructions.

The pilot lights OK with the spark but goes out when I release the gas control knob after holding it for a long time.

I changed the thermocouple but it did not cure the problem.

Any suggestions?

 

[giblets]

Are you sure the thermocouple connections are tight?

If not then sounds like the multi-function control (gas valve) has failed. You will need a CORGI for this as it involves breaking into the gas train and adjusting the new valve.

 

[namsag]

Personally i would suspect the overheat stat that is connected to the thermocouple , very common fault on these boilers

 

[giblets]

Again, you are right, namsag.

Should have had some sleep today rather than answer posts on the Forum after spending from 0300 yesterday tearing about the Solent taking pictures of racing yachts.

 

[bobb]

Personally i would suspect the overheat stat that is connected to the thermocouple , very common fault on these boilers

i have the power off when i try to light the pilot so would the overheat stat affect this?

 

[ChrisR]

Yes. Power comes from the thermocouple, though the stat, to the coil in the gas valve, to hold it open.
If you have a multimeter put it across the stat contacts. Shouldn't be more than about 4mVdc with the flame alight.

 

[namsag]

Having power on or off to this boiler while lighting pilot will not have any effect on operation of the overheat stat attached to the thermocouple .
Overheat stat can be checked by disconnecting it, and just putting the thermocouple straight into the gas valve if pilot holds you know that it is overheat stat if it doesn`t then its the gas valve( providing your new t/couple has been positioned in the flame correctly)

Do not use boiler with overheat stat disconnected this is for testing only

 

[bobb]

Power comes from the thermocouple, though the stat, to the coil in the gas valve, to hold it open.

So, Chris, to be clear, the fact that the pilot won't stay alight with power off the boiler means the problem is not the thermostat. Correct?

 

[Dan Robinson]

the fact that the pilot won't stay alight with power off the boiler means the problem is not the thermostat.

Thats not clear.... but to answer the point - the pilot light is totally independant of the electricity supply. If the overheat stat is dead you'll need a new one. Otherwise you'll need a new gas valve. Either option needs a registered installer.