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 Frozen vent pipe roof vent
Author: sbergerson (MN)

The temperature has been around zero for the past week. All the traps in my new house are getting sucked dry when the washing machine empties. I know from prior experience that my 4 inch roof vent is frosted shut.

About 10 years ago, I learned the simple cure... Cut the vent pipe off at about a 45 degree angle. By doing this, you increase the size of the opening and the frost will not be able to go from one side to the other like it can in a square cut vent.

Just got down off the roof.... should be the last time.

Hope this helps somebody.

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 Re: Frozen vent pipe roof vent
Author: PlumberManDan (IA)

That is a good idea, It may not look very good from the street but I bet it will work for you. You would not have had to slice it at a 45, Oh, BTW, What size pipe is it that you were working on? And is it the ONLY VTR on the house?

PlumbCat TM 2003


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 Re: Frozen vent pipe roof vent
Author: oncall

I wonder if it would help to put a "hook" or an upside down trap on the vent to act as a condensation buffer. Then paint that sucker black to collect heat. I'm glad it doesn't get that cold here....usually!;-)


Edited 1 times.

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 Re: Frozen vent pipe roof vent
Author: hj (AZ)

It can either do it down lower, or just take longer to to around the larger circumference.

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 Re: Frozen vent pipe roof vent
Author: Edmplumber (Non-US)

I've never heard of 4" freezing shut, and I live in Canada where it is -20F right now but it gets a lot colder than that. Thats a good tip though. I'm sure I will use it someday because when I drive down the street there are some scabs who put 2" through the roof(which is to code but not realistic here). I only put 4" through.

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 Re: Frozen vent pipe roof vent
Author: Donavon (MN)

I connect my clothes dryer exhaust vent up to my septic vent pipe clean out (in the basement) and run about 10 minutes of hot air up the pipe. It melts all the ice and I'm good until the next arctic blast. I don't need to go up on the roof and my wife stops doing the genetically predisposed verbiage.

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