Thorn Apollo 15/30 System

[hologram]

I had to drain the c/heating system to change a rad valve but when completed and boiler switched on, it fired up but was noisy. After a couple of bangs and creaks the boiler shut down. Also the pilot wont stay lit.

I'm assuming it could be the overheat shut off thermostat as a new thermocouple was fitted about 6months ago

Thanks in anticipation

 

[Agile]

It sounds as if the pump is air locked or not working and you have no water flow.

Tony

 

[hologram]

When power to the boiler is switched on i can hear water circulating in the boiler .

 

[Agile]

When power to the boiler is switched on i can hear water circulating in the boiler .

You don't normally hear water circulating!

I think you mean you are hearing water with AIR !

I expect its severely air locked. bleed the pump and put pump on "3" to help to clear it.

Its quite possible your feed pipe is blocked!

Tony

 

[hologram]

Just bled the pump and there was quite a bit of air there but pilot will still not
stay lit when igniting the boiler

 

[namsag]

Overheat stat/ t,couple/ gas valve/ or pilot flame not in correct position

 

[Agile]

Its possible that letting it overheat has caused the overheat stat to open and it has not reclosed with a low resistance contact on cooling.

Others will confirm but I thought that your boiler has an auto closing thermostat. Its still possible that its a manual reset but you would probably already know that if that was the case.

If you could safely access the o/h stat you could measure the resistance AFTER disconnecting the thermocouple from the gas valve.

The O/H stat must have a very low resistance of less than about 0.1 ohm.

A better way to check it is to measure the voltage with the thermocouple being heated. The o/h stat should not have more than about 1-2 mV across it.

Tony

 

[hologram]

Cured.....Turned out to be the thermocouple wasnt near enough to the pilot to maintain temperature, Some adjustment to the pilot shield and system is now working fine .

Thanks for all the advise.