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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Heil furnace model #NUGE125LH02 which is short

Customer Question

Hello, I have a Heil furnace model #NUGE125LH02 which is short cycling.
It will cycle on heat up, fan will start, then the gas and flames will stop--the fan will
stay on--5-10 seconds later it will ignite again and keep this process going until
the thermostat is satisfied. Pressure switch and fan control seem fine.......
Submitted: 13 days ago.
Category: HVAC
Expert:  HVAC Guru replied 13 days ago.

Hello, one minute while I get some information together.

Expert:  HVAC Guru replied 13 days ago.

Hello and thanks for using this service! If you are a JA Member I would like to personally thank you and welcome you back! I am HVAC Guru an extremely experienced tech on the site and I try to get to as many customers as I can. NOTE it takes time for me to type research and add links so please wait for me to respond back I can only do this so fast. Secondly, I do not know your skill level so please try and let me know if I am going beyond your knowledge or comfort zone thanks! I strive for a 5 star rating from everyone especially our JA members.

Does the flame go out after the few seconds?

Customer: replied 13 days ago.
Expert:  HVAC Guru replied 13 days ago.

Have you tried to clean off the flame sensor with some fine sand paper?

Customer: replied 13 days ago.
This model according to the manual does not have a flame sensor
Expert:  HVAC Guru replied 13 days ago.

Yes it should part #22 at this link


Customer: replied 13 days ago.
the manual shows the this model on the functional replacement parts says no
Expert:  HVAC Guru replied 13 days ago.

Can you check on the furnace and see if it is there?

Customer: replied 13 days ago.
Expert:  HVAC Guru replied 13 days ago.

Just let me know it should be there

Customer: replied 13 days ago.
there is no long flame sensor, nothing but a spark igniter.....there is a limit switch ( #23 in the manual)
no long flame sensor with wiring on this model like the replacement parts manual says
Customer: replied 13 days ago.
Customer: replied 13 days ago.
Customer: replied 13 days ago.
good-bye---I am not satisfied with your service!!!!!