Sticking K6466 gas valve

[Monkfish]

Hi, I've got an old Glow Worm central heating boiler. This unit uses K6466 gas valve but I understand that K9049 is a more recent replacement.

I'm sure the valve is sticking because it is getting 24Vac power and I can hear it trying to click on (very faint). If I tap the valve unit with a hammer the boiler fires up, sometimes with a low flame until I tap it again.

Before I shell out 100 notes on a new valve, could it be the thermocouple? Is it possible that the thermocouple is right on the brink of enabling the valve and that a tap is tipping it over the edge? If I reposition the pilot flame splitter (which may have been moved during yearly cleaning), might that help? Or does the thermocouple have an either/or operation that couldn't produce a low flame? And would the thermocouple function be affected by tapping?

What could cause the valve to stick — just wear through old age?

Thanks

 

[Agile]

Its not connected with the T/C.

Changing a gas valve is a job for a CORGI.

Gvs stick either due to mechanical wear or from Glycol put into gas supplies by Transco making the seats sticky.

Hitting parts with a hammer is not recommended!

Tony

 

[Monkfish]

Thanks Tony. Sounds like it's time for a new boiler.

 

[Agile]

A new condensing unit will save about 30% on gas costs but will cost perhaps about £2000.

Repairing the old one will be less than a tenth of the cost but will consume more gas.

You need to look at gas consumption costs to decide!

Tony

 

[chrishutt]

A new condensing unit will save about 30% on gas costs

Really that much? I thought the likely figure was around 15%. Makes a big difference to the calculations!

 

[kevplumb]

A new condensing unit will save about 30% on gas costs

probably will

it is likley to spend more time broken down than working