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Can anyone tell me this pipe's purpose?

1351 Views 11 Replies 7 Participants Last post by  HVAC1000
Its in my utility room with the furnace, gas water heater, washer/dryer, etc. It goes up into the ceiling and across my home and leads to an exterior vent on the opposite side of the house. Its has a constant flow of exterior air coming from it and I'm fairly certain its the cause of my chilly basement. I have a radon mitigation system in place so that probably helps to draw air through this pipe as well. I'd really like to close it off but a friend has mentioned it probably is to provide fresh air for furnace combustion however my furnace and home are only 11 years old and I thought one of the two PVC pipes off the furnace was for the fresh air.

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It is for combustion.......though it should not have the 180 degrees of elbows on it.... Is your dryer gas?(combustion) Is your water heater gas (combustion)?
Dryer is electric, water heater is gas. So plugging it or covering it with a towel may be a bad idea then?
unless the appliances have been changed since the house was built then it was put there for a reason.
Well, that's not really what I want to hear. :wink:

Any suggestions to help with the amount of flow or temperature without sacrificing its purpose? It really does move at a good rate...
Reduce it down to about 2 square inches and your gas water heater will be just fine.
It is for combustion.......though it should not have the 180 degrees of elbows on it.... Is your dryer gas?(combustion) Is your water heater gas (combustion)?

Thats a J hook, its to help prevent excess air from coming in when the furnace isn't running.

Of course if the clothes drier is running, then air will come in through it.
A fresh air duct going from outside into the return duct and adding a supply in that room would help. The only reason that pipe in the picture has a lot of flow is because the home and/or the utility room are in a negative pressure. Eliminate the negative pressure and there will be almost no cold air dumping out of it.
you can extend that pipe down and end it in a 5 gallon bucket (the kind you get at home depot) about 6 inches from the bottom of the bucket. this will make a cold air trap and the cold air will only come out when it is being drawn by and appliance
you can extend that pipe down and end it in a 5 gallon bucket (the kind you get at home depot) about 6 inches from the bottom of the bucket. this will make a cold air trap and the cold air will only come out when it is being drawn by and appliance
Thats what the j hook is for. The Op has something causing a negative draft in that room. So the cold air would be coming out of the bucket too.
beenthere said:
Thats what the j hook is for. The Op has something causing a negative draft in that room. So the cold air would be coming out of the bucket too.
Opps! Your right. I didn't see it the first time I looked at the picture, these phone screens are getting too small haha
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