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Heating, Air Conditioning, Fridge, HVAC/15 year old Keeprite DC90 furnace


Hi! Combustion fan comes on, ignitor glows, gas valve opens, & when burners iginite not all the time but sometime it make a loud rumbling noise.This has been going on for 2 years but otherwise hasn't failed yet. I have a co2 detector 3 ft away from the furnace. Other than a vacuuming & filter replacement do the burners require any maintenance ?

Thank you kindly,

Hi Norm,

The rumbling noise your hearing might be because the furnace is over firing. The gas pressure on the outlet of gas valve is to high. Eventually this will damage the heat exchanger.

You could take the burners out and clean them. Also check the color of the flames, they should be blue. If they have orange in them the burners need adjustment.

Let me know if you have any other questions.

Heating, Air Conditioning, Fridge, HVAC

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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!

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