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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have tried to light the pilot light on a gas furnace. The

Customer Question

Customer: I have tried to light the pilot light on a gas furnace. The pilot with not light but I get a large flame while trying to light the pilot. I have replaced the thermocouple, the gas valve, the transformer, and the pilot light aluminum supply line. I have tried adjusting the gas flow and pilot light level with the adjustment screws on the gas valve but this makes no difference. The gas company checked the gas pressure just past the meter and it is supposedly normal. Do you have any suggestions for dealing with this?
JA: Thanks. Can you give me any more details about your issue?
Customer: This is an older furnace, a Borg Warner. I have a number of these in this building and no other ones have had this problem.
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to HVAC Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
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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.

You've replaced all the relevant components so I wonder about your thermocouple connection. Is it dry (no pipe dope)and tight at the gas valve? is only the top 1/3 (max) of the thermocouple in the pilot flame?

Customer: replied 1 year ago.
At first, more than 1/3 of the thermocouple was in the flame as the fitting pushed it far forward. I then tried it with the end lined-up with the pilot and it made no difference.
Expert:  Rick replied 1 year ago.

Do you have a strong pilot? You need more that just the tip of the thermocouple in the flame the top 1/4 should be engulfed by the flame.

Customer: replied 1 year ago.
I have no pilot. I have tried putting the end of the thermocouple all the way into the flange that holds it; this puts the end way forward from the pilot and I have tried putting it lined-up with the pilot. Either way, the flame is large when I push the starter button and the flame is gone when I turn the control to pilot.
Expert:  Rick replied 1 year ago.

Your description doesn't add up. You shouldn't be able to even light the pilot unless the indicator is set to pilot.