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Can I extend my fresh combustion air intake pipe?

I have a 7 year old Ryan home in Fairport, NY. The forced air heater was installed with a fresh combustion air intake and exhaust using PVC pipe plumbed to the outside. I believe it is 3" OD, the pipe exit the house just 10" or so from the ground level. The fresh air intake immediately has a 90 degree elbow pointing down to the ground. The exhaust pipe extends upward about 2-3 feet and points away from the house with another 90 degree elbow. The problem I have is during the winter months when we get a lot of snow, the winds tend to create drifts as high as 5 feet in this corner of the house. The strong suction of the fresh air intake crystallizes the cold, moist air in the 90 degree elbow until ice formation finally obstructs the pipe completely. The safety pressure switch ofcourse shuts the system down and the heater fails to function every time it tries to cycle. I then have to manually clear the obstruction and reset the system per instructions.

To resolve the problem I thought of extending both pipes upward about 4-5 feet maintaining a safe distance between the exhaust outlet and fresh air inlet per the instructions. My question is, can I do this without affecting any volumetric settings or anything else with the system? I'm pretty handy and it seems like a simple job, just want to make sure I don't compromise the system further.

The furnace is a a York Diamond 90 model #G1UA048S21B with a 92.2 AFEU Efficiency rating.

Thanks for your insight and direction, winter will be here soon !


Re: Can I extend my fresh combustion air intake pipe?

Take a look at the link below,it looks like 60" is the max height you can extend.You need to use the correct pipe.
Do you have the manual,I would call the manufacture tech support help center. They for sure wil be able to answer your ?


Re: Can I extend my fresh combustion air intake pipe?

If all you are trying to do is raise the Concentric or exhaust and intake up 4-5 feet and you are within the allowable intake pipe length you should be OK. You have to take into consideration loss of length because of 90 and 45 degree fittings, 1 90 = 6', 1 45 = 3'. For example if your intake pipe length can only be 30' (per manual) and you have two 90s and one 45 your straight pipe can only be 15'. I think the 60" would have to do with lengthening the Concentric itself. I can't believe they terminated so close to the ground. That wouldn't fly in MA. Make sure the exhaust is the correct height above the intake and make sure you have enough room if you are terminating under a soffit. Good Luck!!! :)

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