WE HAVE A COZY GAS HEATER HAVE TRIED TO REPLACE THE THERMAL COUPLING AND THE HEATER LIGHTS AND SHUTS OFF AFTER FIRST CYCLE WHAT ELSE COULD IT BE IT HAS A HEAT SENSOR ON THE BACK COULD IT BE THAT

you either have a back draft blowing out the pilot light, or a bad thermal coupling. if coupling is bad it will shut down the gas flow therefore shutting off pilot light. its a safety measure to stop the gas flow if pilot goes out. replace thermal coupling, that may do it. good-day ! but shut off gas first !

if it keeps going out, its more likely the thermal coupling is bad and needs replaced. if the coupling goes bad it shuts gas of to heater as a safety precaution. it does not let any gas come out of the main regulator. it works on the principal when the end gets hot it opens the gas valve and lets gas through to burner. replace coupling. have a good day !!

sounds like the thermal coupling is starting to go bad and it is shutting down the gas valve.
replace it and see if it improves the units performance.

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sounds like a bad thermal coupling! if the coupling goes bad it will shut gas supply off as a safety precaution. it acts similar to a thermometer, if its bad then you will not get any gas through. it is screwed into gas valve and shuts the gas off. have a good day!! replace thermal coupling!

the thermal coupling may be bad!! if the coupling goes bad it will shut down flame. its a safety feature, if gas comes out, and no flame it shuts gas off. the coupling is in pilot light flame and works on the same principle as a thermometer to sense the heat. good luck !!

it may be the thermal coupling. because if its bad it will shut the gas off. if the coupling gets hot on the end, it will turn gas on. it has to be in pilot light flame, to turn gas on. change thermal coupling. good luck !!

check the thermal coupling for the pilot light. if it goes out it will shut down gas supply, its a safety feature to put out pilot light if the thermal coupling is bad. to prevent gas from leaking and causeing a fire. check coupling.

if its gas and will not light. its probably a bad thermal coupling. if they do go bad it shuts down the gas as not to cause a disaster. ( for safety ). replace thermal coupling. they are fairly cheap. but get one the same length as old one. or a bit longer.

go to www.cozyheaters.com for full install instructions.

Make sure all the wire connections are good and tight. Next lift off the cover and look for a little thermal disc mounted up by top of the heat exchanger. Most have a re-set button but not all. If you have this ,by-pass it ,see if that solves the problem, if so it may be defective, or doing its job and you have a venting problem. If you don't have this and have changed the thermocouple (was it a copper tube with a fitting that screwed into the gas valve, or did it have 2 wires, that is a pilot generator, kind of same thing) make sure the probe is set correct, with the pilot flame heating the top 1/3rd of the probe. The only thing left is the gas valve.