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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a 1997 F-50-3 Reznour furnace that I cannot keep the

Customer Question

I have a 1997 F-50-3 Reznour furnace that I cannot keep the pilot light lit on. Last year I replaced the main valve and thermocouple assm. as it was doing the same thing. After several attempts to get it going it finally stayed lit and worked thru the heating season. This year when I tried to relight the pilot (I assumed it blew out over the summer months) it will not stay lit so I replaced the thermocouple but that didn't help. Thoughts?
Submitted: 1 year ago.
Category: HVAC
Expert:  Rick replied 1 year ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

Do you have a strong pilot? is it engulfing only the top 1/3 of the thermocouple?

Customer: replied 1 year ago.
I believe so.
Expert:  Rick replied 1 year ago.

Is your thermocouple connection at the gas valve dry (no pipe dope)and tight?

Customer: replied 1 year ago.
it is dry and tight. Out of curiosity... Can you over tighten the thermocouple into the valve? What is the part called and what is it function that the end of the thermocouple end touches when screwed in? It has red wires that clip to it.
Expert:  Rick replied 1 year ago.

You have a terminal block with wires attached in the thermocouple? connected to the thermocouple?

Customer: replied 1 year ago.
in the valve body there is a piece that goes into it that that has 2 red wires attached and when you thread the thermocouple into the valve body it holds this piece in place. The new valve body came with a new one but they are replaceable. I assume that they have something to do with keeping the pilot lit so if I knew what they were called I could try replacing that part as well
Expert:  Rick replied 1 year ago.

Ok, now we're getting somewhere. It's probably what's connected to the other end of those leads that's the problem. That thermocouple terminal block isn't a likely culprit. Just for testing purposes disconnect those 2 leads and jump those terminals and see if the pilot lights

Customer: replied 1 year ago.
ok this will take a few minutes. hang loose.
Expert:  Rick replied 1 year ago.

Ok

Customer: replied 1 year ago.
OK I jumpered the red wired out no change so I jumped the block out as well and go no change there as well. The pilot will not stay lit.
Expert:  Rick replied 1 year ago.

Is the block removable? if so remove it and connect the thermocouple directly to the gas valve and try lighting it

Expert:  Rick replied 1 year ago.

If it still won't light give me a picture of the gas valve and thermocouple connection

Customer: replied 1 year ago.
The block is removable the wire clips are part of the block. I will get some pics.
Expert:  Rick replied 1 year ago.

Ok so get rid of it and connect the thermocouple directly

Customer: replied 1 year ago.
It's not letting me add pictures to the site, Do you have an email address I can send to?
Expert:  Rick replied 1 year ago.

I can see the pic. Not what I expected. So you jumped the 2 terminals that the red leads are connected to and it won't stay lit?

Customer: replied 1 year ago.
I jumped them both ways. I jumped the wires and I jumped the spade clips.
Expert:  Rick replied 1 year ago.

I got nothing else. Maybe one of my colleagues has an idea. I'm going to open this backup to my colleagues so one of them can help. Please don't respond (even to acknowledge this post)until you get a response from us. If you respond first it will only delay your answer.

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