Testing Thermocouple

[pollys13]

Hi,
I have a Apollo 30/50B gas boiler. It will not ignite, see my other post regarding this. Bought a new thermocouple, still no joy. The new one has crimping marks, thought this might interfere with its conductivity. Is it possible to test the thermocouple to see if working? Perhaps with a voltmeter?

 

[joop1977]

Does the pilot actually ignite in the first place?

 

[rocky2]

possible gas valve fault

 

[Gas2Air]

Hi,
I have a Apollo 30/50B gas boiler. It will not ignite, see my other post regarding this. Bought a new thermocouple, still no joy. The new one has crimping marks, thought this might interfere with its conductivity. Is it possible to test the thermocouple to see if working? Perhaps with a voltmeter?

Yes there is a test, but you would know that seeing as you may have affected the integrity of the appliance by fitting the TC, also you should know that the O/H stat should be checked too, i assume you may ask why?.

 

[Gees]

The thermocouple provides a current to hold open the gas valve. The voltage produced is very low although it can supply a fair amount of current.
As mentioned above does the pilot light at all???
I had an old gemini combi years ago and i had two gas valves fitted to rectify a similar problem. On examination both times the electromagnet wiring had become disconnected inside the valve... Maybe the same with yours?

 

[powell30]

Difficult territory here.....i am assuming (correct me if i am wrong) you are not gas qualified (ACS, CORGI?)technically a thermocouple is a safety device and as such should be fitted by an RGI.......however, it appears you have already gone ahead and tried to fit a new one and not resolved your problem.

Get a professional in to fix the boiler