Heating, Air Conditioning, Fridge, HVAC/furnace won't ignite


I have a Heil Quaker Tempstar Model #NRGF36EDB02 furnace/air conditioner unit (1988).  During the monsoon rains this summer water got into the unit through the drain port below the cooling radiator.

The depth of water was 4-6 and could have reached the burners.  I have cleaned out all the debris and replaced all the insulation in the unit and the connecting ducts.  The main furnace fan motor (blows hot air into the ducts) shorted due to my mistake when reinstalling the wires and will need to be replaced.  

Before going to that expense I want to test the furnace itself to make sure it works.  My question is, since I have the main furnace fan motor out of the unit, when I try to get the furnace to ignite the small blower motor starts and works fine but the furnace never ignites (no flame seen through the inspection window).  Nothing gets hot.  There is also no natural gas odor,

Does the main furnace fan have to be plugged in for the system to ignite?  

I am planning a major remodel in the next year and am trying to nurse this system along for another heating season before replacing it.


Hi David, I have never tried to ignite a furnace with out a fan. But in theory it should ignite. You will probably get flame for maybe a minute, then high limit will shut down the gas valve because there is no air flow.

If your combustion fan is running then it could be a number of problems. You would have to test the fan pressure switch to make sure it is closed when the fan is on.

I have not been able to find any info on your particular unit. Without a wiring diagram thats about all I can tell you.

Let me know if you have any more questions.  

Heating, Air Conditioning, Fridge, HVAC

All Answers

Answers by Expert:

Ask Experts


Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

©2016 About.com. All rights reserved.