# maintenance on high efficiency furnaces



## earl964 (Dec 5, 2007)

Can some one tell me how much annual maintenance is involved in a 4 year old high efficiency furnace. It is a Goodman GMPN120-5 with a LP conversion kit. Filters are always changed and the condesate drain line is always gettig cleaned. I just dont know what else to look for.


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## travelover (Dec 6, 2007)

Do you have the owner's manual?


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## glennjanie (Dec 6, 2007)

Welcome Earl964:
High efficency furnaces with LP gas conversion frequently accumulate soot in the heat exchangers, especially the secondary heat exchanger. I think there is a flexible snake for cleaning them; you might check with the dealer or distributor.
They are also prone to burn holes in the primary heat exchanger. I know they are stainless steel but LP burns so much hotter than natrual gas and I have personally seen this problem. To find it, you can rub your hand lightly along the bottom tube feeling for holes or rough spots. If there is a rough spot an extension mirror and flashlight will give you a better look.
Glenn


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## earl964 (Dec 6, 2007)

is the secondary heat exchanger behind the black colleter box. Is the primary wher you can see the flames inside the tubes.
Thanks for the quick reponses


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## glennjanie (Dec 7, 2007)

Hey Earl964:
You've got it friend. the secondary heat exchanger is made of tubes closer to 1/2" diameter with aluminum fins on it to rapidly exchange the heat. After the exhaust gasses go through the secondary, you begin to get condensation in  the flue which is now only warm to the touch. That's why they have to have a draft inducer, when the gasses are cooled that much it is hard to get it to draft.
Glenn
I was Army but I admire the Semper Fi.


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## earl964 (Dec 7, 2007)

Do I just take that cover off and find a brush that will fit inside those tubes and clean them out.


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