Williams wall heater pilot dies when burner tries to ignite

[ubaisore]

Hello all

I have a Williams wall furnace (P321638) that is having a problem. When thermostat (millivolt type) tries to start the main burner, the pilot goes out. I can keep the pilot lit until I try to start the main burner.

I have done this "test" via the thermostat and via jumping the terminals in the ITT gas valve with equal results.

I replaced the thermopile in the last 3 months. While the pilot was lit, I put tested for mv and got 184. It started at 135 and climbed. There is also a safety switch that is mounted bedinf the cover at about shoulder height. I tested with an OHM meter and got 0.1

I am thinking the new thermopile went bad quickly, and when the main valve tries to ignite it pulls the power that was keeping the pilot open (thereby closing it) and doesnt have enough to open it.

I have read all I can and am still confused about what is wrong. I was thinking about jumping the terminals for the safety (just for a quick test, I realize it is very unsafe to leave it that way) but can't figure out if that would bypass it.

THanks for any help in advance!

[paul52446m]

Hello all

I have a Williams wall furnace (P321638) that is having a problem. When thermostat (millivolt type) tries to start the main burner, the pilot goes out. I can keep the pilot lit until I try to start the main burner.

I have done this "test" via the thermostat and via jumping the terminals in the ITT gas valve with equal results.

I replaced the thermopile in the last 3 months. While the pilot was lit, I put tested for mv and got 184. It started at 135 and climbed. There is also a safety switch that is mounted bedinf the cover at about shoulder height. I tested with an OHM meter and got 0.1

I am thinking the new thermopile went bad quickly, and when the main valve tries to ignite it pulls the power that was keeping the pilot open (thereby closing it) and doesnt have enough to open it.

I have read all I can and am still confused about what is wrong. I was thinking about jumping the terminals for the safety (just for a quick test, I realize it is very unsafe to leave it that way) but can't figure out if that would bypass it.

THanks for any help in advance!

Ok on a millivolt system it is very important that all connection are clean and tight. Is this a 700 power pile, thermopile? Is the pilot burning good and blue, and going all the way around the thermopile, the thermopile is going through the pilot flame and sticks above the flame a little. So if the pilot is not doing all this than it needs to be cleaned out.
After you check all this and have it right , take the stat wires TH &TH wires off the gas valve. Now with just the two PP wires on check the power. What is it? If you get a good test then take a jumper wire and jump from the
THPP post to the TH post and see if it fires up. The reason we check this way is we have to check each thing at a time.
So first pilot, then the thermopile by itself. If you check the electric diagram, this power should go through the stack diverter switch and also through a limit switch and thermostat. So look for any lose wires or bad spots in the wire. Get this far and let me know what happens. Paul

[ubaisore]

Thanks for the Response. I checked power without stat hooked up. I jumped both ways and can't get ittp start, I replaced the thermopile and it fired right u. Is there something that will burn one out prematurely?

[paul52446m]

Thanks for the Response. I checked power without stat hooked up. I jumped both ways and can't get ittp start, I replaced the thermopile and it fired right u. Is there something that will burn one out prematurely?

About the only thing that can damage them is if tor pilot was way to strong, but if that was the case it would show up in testing it. That like new thermocouples, I buy them 10 to a box and some times there are two bad one in that box. I thing they call that quality control !!! Paul

[brettyg]

It sounds to me that you mat have a bad gas valve.

[paul52446m]

It sounds to me that you mat have a bad gas valve.

If you read his message, he said he changed the power pile and got it fixed.
paul

[brettyg]

Im sorry paul i cant read