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Can anyone identify this item please?

Stewart Lawson

Oct 18, 2015
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Oct 18, 2015
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I have a Heatsource 1600 gas heater in the living area on our horse lorry.

It fails to stay on after the purge and ignition stage. It lights but soon fails.

I've checked the gas solenoid and jet and out the vehicle it stays on fine.

I think it's this item in the flame path that's not working but it has no marks or ID on it at all.

normal_image~1.jpeg


Is it a thermocouple as it only has one connection? Maybe a thermopile?

I heated it with my wee burner and got only a few Mv ( 1.9) across connection and bracket.

With it out and a 12v frig across the gas solenoid the burner stays on indefinitely.

Does anyone know what it's actually called and if I'm testing it correctly?
 

duke37

Jan 9, 2011
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That is a thermocouple, the two connections are the outer sheath and the inner wire. They can go open circuit or short across in a cool section.

I do not have such a burner but know of two persons who keep a spare thermocouple.

You are unlikely to get 1.9Mv but the sparks would light the fire:)
The output will be 40μV/K
I think the thermocouple drives the relay directly with a very small voltage. Putting 12V on the relay may be disastrous.
 

Stewart Lawson

Oct 18, 2015
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Oct 18, 2015
Messages
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I checked the voltage the heater supplied to the gas valve solenoid and it is 12v.

I think once the thermocouple is up to temp it holds the solenoid on thereby keeping gas on. If the Thermocouple loses heat it shuts off the gas valve.

Do you know the part number of the pictured couple or where I can source one?
 

duke37

Jan 9, 2011
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I have no information on the thermocouple. You could go to the maker, go to a caravan maker, go to ebay or go to Screwfix. The problem is getting one to fit.

They are made with mineral isulation (magnesia?) between the inner and output. This is sensitive to moisture so the seal must not be broken.

The thermocouple drives a sensitive relay which drives the solenoid.
 

Stewart Lawson

Oct 18, 2015
5
Joined
Oct 18, 2015
Messages
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Thanks for all that info.

I'll contact the makers but as it's gas I assume the Corgi type regulations will regulate whether they can supply directly to me.
 

Martaine2005

May 12, 2015
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May 12, 2015
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Hi Stewart,
Give Sergio Boiler Spares a ring. If you send him a pic from your phone, he will tell you what it is and whether he has any there and then.
This guy is a GOD with all boiler spares and certainly knows his stuff. I have used him for over 20 years.
He is located in Hackbridge. Just outside Sutton. He will post items too.
I'll break up his number...07.836..5.9.9.9.51.

Martin
 
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