Glowworm Ultimate not always firing even though pilot is lit

[jamesih]

Hi,

We have bought a house with a 10 year old Glowworm Ultimate which seems somewhat temperamental.

The pilot is always lit and we always seem to have hot water but if we try to advance the central heating it doesnt always fire up. I have bypassed the wall mounted thermostat and bought a new timer switch but the same thing occurs.

It seems fine if it's left off for a while and then either the timer kicks in or we override it then it will (sometimes) fire up for a while and then after what seems a random period just goes back to the pilot and the heating goes off.

Any thoughts.

Many thanks.

James.

 

[corgiman]

i would say the printed circuit boards is dead

 

[jamesih]

Reading through the posts on this forum I became increasingly sure it was the 3 port valve.

I had tested all the voltages coming from the micro switches into the 10 way which were all fine but nothing was moving on the valve.

I bought a new one from B&Q and before draining and replacing I decided to swap the motor as they were identical units.

Hey presto all working again.

Another failure for a 3 port valve!

James.