Iam firing away with the questions tonight :) Thermocouple testing

[TFGplumbing]

I need to test a the thermocouple on a gas fire is this the correct way to do it?

Multimeter - put it on DC; something like 200 Mv
Positive to the outer core
Unscrew thermocouple out of Gas valve
Negative to the inner core
Light the pilot and see if i get a reading

 

[Millsy 82]

Blimey all I do is look at them if they look dodgy they get swapped. I have got a proper tester in the van somewhere but it doesnt get much use.

 

[andyg0507]

why not just buy a thermocouple tester and save the hassle?

 

[REDSAW]

Check the continuity of your thermocouple with an ohmmeter. A thermocouple typically is a length of two wires that are twisted together at the end. The resistance at the other end between the two ends of the wire should be minimal, less than one ohm.

 

[GrahamM]

Blimey all I do is look at them if they look dodgy they get swapped. I have got a proper tester in the van somewhere but it doesnt get much use.

With you on that one.
If it looks bad and getting good flame and pilot failing, for sake of few quid I change it.
9 times out of 10 it is the T/C or poor pilot at fault.

 

[TFGplumbing]

cheers for the advice guys

 

[stevetheplumber]

if you get an old gas valve you can get the thermo couple bit out to use\ as a tester if testing with a meter as you said dc volts should be above 12 mv not sure you can test for continuity as they can fail either way

 

[stevetheplumber]

you can test the gas valve end by screwing in a new one and warming the tip with lamp not unknown for that end to fail as well

 

[diamondgas]

I need to test a the thermocouple on a gas fire is this the correct way to do it?

Multimeter - put it on DC; something like 200 Mv
Positive to the outer core
Unscrew thermocouple out of Gas valve
Negative to the inner core
Light the pilot and see if i get a reading

Hi TFG, in answer to your question yes, but the + & - maybe the other way around, not sure? You're only looking for about 30mvdc so you may need it on a smaller scale A crocodile type connector for the multimeter are handy coz you can just clip it to the outer sleeve! You've got to be a bit of an octopus because you've got to keep the pilot button pushed in whilst jiggling probe leads and t/cuple ...lol

 

[kirkgas]

Hi TFG, in answer to your question yes, but the + & - maybe the other way around, not sure? You're only looking for about 30mvdc so you may need it on a smaller scale A crocodile type connector for the multimeter are handy coz you can just clip it to the outer sleeve! You've got to be a bit of an octopus because you've got to keep the pilot button pushed in whilst jiggling probe leads and t/cuple ...lol

i always find it too fiddly to test with multimeter, i use a thermocouple tester, its quicker and easier, was only a couple of quid, but as others have said if you are scrapping a gas valve you can pull the thermo valve out of it and use that, depending on the boiler it is actually easier to stick a new thermocouple in rather than test with anything

 

[kirkgas]

I need to test a the thermocouple on a gas fire is this the correct way to do it?

Multimeter - put it on DC; something like 200 Mv
Positive to the outer core
Unscrew thermocouple out of Gas valve
Negative to the inner core
Light the pilot and see if i get a reading

too many hands required haha

 

[diamondgas]

i always find it too fiddly to test with multimeter, i use a thermocouple tester, its quicker and easier, was only a couple of quid, but as others have said if you are scrapping a gas valve you can pull the thermo valve out of it and use that, depending on the boiler it is actually easier to stick a new thermocouple in rather than test with anything

I can count on one hand how many t/c's I've tested. If I suspect the t/c or pilot flame I've been known to stick a temp t/c in the valve and heat it with a lighter. If the gas valve holds open then I'll replace the t/c and clean out the pilot

Did you know that the encapsulating valve is now obsolite?

 

[TFGplumbing]

Well I ordered a new thermocouple for it.... and the custard has got it working again now somehow.... heavens sake, There was no way it was lighting when i was there even if u let the pilot play on the tc for frick'n ages.

 

[diamondgas]

Well I ordered a new thermocouple for it.... and the custard has got it working again now somehow.... heavens sake, There was no way it was lighting when i was there even if u let the pilot play on the tc for frick'n ages.

:rofl: It'll go out again, just wait

 

[TFGplumbing]

Its a cannon coalridge bf, jesus are those hard to get parts for. I serviced it on tuesday. It was in Ok condition, could have done with a new rear burner it was ever so slightly corroded cant even get them any more. burner pressure was ok. I dont think is was burning the best it possible could have been, however it is a flame effect fire and it is 20 years old

 

[diamondgas]

Its a cannon coalridge bf, jesus are those hard to get parts for. I serviced it on tuesday. It was in Ok condition, could have done with a new rear burner it was ever so slightly corroded cant even get them any more. burner pressure was ok. I dont think is was burning the best it possible could have been, however it is a flame effect fire and it is 20 years old

Universal fire t/c may fit? It's different to the universal boiler t/cupl. The coalridge has the collar in the termocouple yeh?

 

[TFGplumbing]

yeh its a funny one that you sort of have to screw through a little collar on the fire casing. its not part of the pilot assembly, ive managed get one now they dont fricking want it.. grrrr

 

[diamondgas]

I bought a flippin £150 quid pcb last month that wasn't needed!!!! Duh!!! lol

Such is life..... thankfully few and far between TFG I'm still reeling :banghead:

 

[TFGplumbing]

Profit margins lol, I am quiet atm :wink5:

 

[diamondgas]

Well this year at the mo I'm in negative equity ... flippin van had me off the road for a day today and cost me £160 :banghead:

 

[midge]

If it shows any signs of stress bin it. If you 'need' to test it, establish the pilot light and turn off the gas. Start counting, if it lasts 30 seconds before you hear the valve go click it is as good as new, if it only lasts 10 seconds bin it.

In fact just bin it anyway, charge for a new one and be thankful you won't get a recall!