Propane fireplace issues

[nhtc33d]

Hello all,
I have a propane fireplace that will not light the main burner from the wall thermostat. BUT....If i turn the main burner switch on and unplug the thermostat from the wall then it will light!! Then if i plug the thermostat back in to the holder it shuts the fireplace off. I replaced the thermopile and that didnt help. Any ideas??

[paul52446m]

Hello all,
I have a propane fireplace that will not light the main burner from the wall thermostat. BUT....If i turn the main burner switch on and unplug the thermostat from the wall then it will light!! Then if i plug the thermostat back in to the holder it shuts the fireplace off. I replaced the thermopile and that didnt help. Any ideas??

You are losing too much power through your wiring and through the thermostat.
Or you could have the two wires shorting out some where between the fire place and through the stat. Is the thermostat the right one for a millivolt system??
You have to make sure it is made for millivolt. Do you have a good clean pilot
that is going around the thermopile so it can produce enough power. Make sure all wire connections are clean and tight. Try taking the thermostat off and jumping the wires at that point. If that works the problem will be in the stat,
or you have the wrong thermostat and it is draining too much power off the circuit. You did get the right thermopile?? Later paulbm

[nhtc33d]

Thanks for the reply,

You are losing too much power through your wiring and through the thermostat.
Or you could have the two wires shorting out some where between the fire place and through the stat. Is the thermostat the right one for a millivolt system??


***I will check the resistence on the wiring, The t-stat is for a millivolt system. Its the same one thats been on the system and has worked fine up till this point.***



You have to make sure it is made for millivolt. Do you have a good clean pilot
that is going around the thermopile so it can produce enough power.


***The pilot is it touching thermopile and thermocouple by 1/4 in.***


Make sure all wire connections are clean and tight. Try taking the thermostat off and jumping the wires at that point. If that works the problem will be in the stat,


***Tried the jumper idea but still didnt turn on fireplace***


or you have the wrong thermostat and it is draining too much power off the circuit. You did get the right thermopile??


***I was told by the fireplace dealer that is was the correct one but i will have them double check.***

Later paulbm

Thanks again for the reply and help!

[HayZee518]

the thermostat is just a switch - its either on or off. the millivolt generator is a j-k thermocouple that produces a DC voltage when its heated. [dissimilar metals generate a dc voltage when its junction is heated] the generator feeds its signal to a super small and sensitive electromagnet within the main valve body.

[paul52446m]

Hello all,
I have a propane fireplace that will not light the main burner from the wall thermostat. BUT....If i turn the main burner switch on and unplug the thermostat from the wall then it will light!! Then if i plug the thermostat back in to the holder it shuts the fireplace off. I replaced the thermopile and that didnt help. Any ideas??

Sometimes it is hard to check a problem like yours with out having a millivolt
tester Your thermopile only has to produce 25 millivolts to keep pilot on .
Your gas valve , depending on which one you have, take any where from
85 to 240 millivolts to open the valve. So you might have to have a serviceman
with a millivolt tester to check it out. Later Paul

[nhtc33d]

Sometimes it is hard to check a problem like yours with out having a millivolt
tester Your thermopile only has to produce 25 millivolts to keep pilot on .
Your gas valve , depending on which one you have, take any where from
85 to 240 millivolts to open the valve. So you might have to have a serviceman
with a millivolt tester to check it out. Later Paul

Thanks again for the reply,
I checked the thermopile with my millivolt tester and it is reading around
105. I tried heating it up to 240+ and still did not turn on. Keep the ideas coming!!

Thanks again, Mark

[paul52446m]

Thanks again for the reply,
I checked the thermopile with my millivolt tester and it is reading around
105. I tried heating it up to 240+ and still did not turn on. Keep the ideas coming!!

Thanks again, Mark

You say you checked with a millivolt tester. Very few people have a millivolt
tester. What scales do you have on your tester? Most electrical testers do not have millivolt testing on them. They test DC volts but not millivolts.
If you do have a millivolt tester,then test between PP and PPTH and tell me what the reading is. Then test between PP and TH and tell me what the reading
is. The PP to TH test is where you have to have between 85 and 240 to open your gas valve, depending on the gas valve you have.
I don't know how you heated up the thermopile, but if you put a LP torch
on it you will damage it real fast. Later paul

[nhtc33d]

well i got it fixed!! There was a misprint in the wiring diagram
in the manual. I just had to move 1 wire to another terminal on the gas valve.
Thanks again for all the help!