How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Tim H. Your Own Question
Tim H.
Tim H., HVAC Professional
Category: HVAC
Satisfied Customers: 3971
Experience:  Experienced in all aspects of HVAC, both residential and commercial.
Type Your HVAC Question Here...
Tim H. is online now
A new question is answered every 9 seconds

My gas furnace will not heat. At first the red light flashed

Customer Question

My gas furnace will not heat. At first the red light flashed 4 times so I assumed it was the igniter; once I hit the breaker, it quit flashing. I viewed the gas pilot light flame but after a few minutes the furnace quit. The unit actually warmed up and then quit. It is a small furnace for our upstairs addition. Any tips?
Submitted: 1 year ago.
Category: HVAC
Expert:  Tim H. replied 1 year ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need. What happens at the furnace when you call for heat? Can you tell me step by step what the furnace does? Do the burners light, even if only briefly?

Customer: replied 1 year ago.
Burner did light briefly
Expert:  Tim H. replied 1 year ago.

Have you tried cleaning the flame sensor?

Customer: replied 1 year ago.
How do I do that; the book does not tell me how to get to it.
Expert:  Tim H. replied 1 year ago.

If you have HSI (hot surface ignition), there should be a flame rod in by the burners. May look like this. It is usually removed with one screw. Shine up the metal part with steel wool or emery cloth, then replace.

Customer: replied 1 year ago.
I will try to locate it now
Expert:  Tim H. replied 1 year ago.


Customer: replied 1 year ago.
Is it in the compartment with the control board?
Expert:  Tim H. replied 1 year ago.

In by the burners. On the opposite end of the ignitor that glows orange and lights the burners.

Expert:  Tim H. replied 1 year ago.

Also, please recheck that model number. I am not pulling anything up with that model.

Customer: replied 1 year ago.
Your solution did not work ; it was extremely diff to remove but I did get it, cleaned it and put it back. As soon as it ignites a switch pops and shuts it down.😥
Expert:  Tim H. replied 1 year ago.

What switch?

Expert:  Tim H. replied 1 year ago.

Since I don't have a model number that is pulling anything up, I am trying some of the basics. I did not say cleaning flame sensor would definitely be the solution. We are just eliminating possibilities here. If you can tell me which switch "pops" and shuts unit down, this will help us get closer to a solution.

Customer: replied 1 year ago.
I have called an expert; nothing you have suggested has helped. Thank you anyway. Tried to text you yesterday but could not get through.
Expert:  Tim H. replied 1 year ago.

OK, I can certainly understand your decision to call a pro. Even though we were just getting started in trying some things. Let me know the outcome.

Related HVAC Questions