I have a Superior GDV-5000L LP gas fireplace. Pilot stays lit but gas valve will not turn on with wall switch until I momentarily jumper across the thermopile contacts on the gas valve. Wall switch circuit measures about 2.5 ohms and will keep the gas valve open once I jumper across the thermopile. However, when the wall switch is turned off, it will not open up the gas valve again until I momentarily jumper across it. Thermopile output is about 115-200 millivolts. That seems a little low. Any suggestions?

Sounds like the thermopile is a little low on millivolts. Not enough power being generated to travel the distance to the wall switch and back. Make sure all connections are clean.

Thanks hvac1000 for the quick response. I cleaned all the connections and tried wiring across the switch. Same problem. I thought most thermopiles had outputs of 300-600 mv. I'm thinking I have insufficient current flow to actuate gas valve. Knowing the minimum current required would be useful.

There are many different thermopile setup and many of them use different millivolt power requirements. Example of measurements for you to use.

Dang it I forgot the other part.

Thanks for the diagrams and check table. It describes my system exactly. At check B I measure 200 mv or less. I'm sure the current required to actuate the magnetic valve is greater than the current required to maintain it in a closed position. That may explain why I must momentarily jumper TH-TH/TP to ignite the main burner but the wall switch will keep the burner on when the jumper is removed. Looks like I'm in the market for a new thermopile. Thanks for help.

No problem I hope it works out for you.

I just worked on one. Unit would work when turned on the millvolts was 200ish when box got hot 10 min. the unit would shut down millvolts dropped down to 150. Moved wires around aand would go back up to 200. Put new power pile in and when unit was off over 600 millivolts(meter only went to 600)when turning unit on it dropped to 500ish everything works good now. Hope this helps. Pulling pilot out to change not so fun...

greghvacguy if you had 500ish on a fireplace milivolt system you might have the wrong generator in there. The FP units are not standard old furnace milivolt units.

That was the part the fireplace manufactor sent us.I called them gave m# ans s# and they sent out the power pile and fast action thermocouple(fir I will change thermocouple since I was pulling pilot out. Hope they got it right.Since I don't work on many fire boxes I would call them and get OEM. Hope they sent out right part. Benn if for a 2 weeks and have not got call back... Thanks for the heads up

If it came from the MFG then it should be OK. Many years ago when the gas fireplaces first became popular I got an education on the different types and millivolt generators since coming from the heating end of things I thought there was only one. The 750 standard millivolt generator used in all the old furnace styles did not work well on the new style gas fireplaces. Usually 350 to 400 is the standard reading when dealing with the FP's

Where can I find parts for a Superior GDV 5000 Direct Vent Gas Fireplace live in CT. I understand the company no longer exist.