Has anyone ever seen a valve like this on the PVC exhaust?


Yes, but I have no explanation as to why it is there.

Isn’t that the combustion air intake side?

The one that I saw was on the intake. It was a farmhouse, and all I could figure was they closed it in warmer weather (no a/c) to keep rodents out. (vacant home, no seller to ask).

That was my thought as well.:wink:

Probably not good if it is not open during the heating season.:shock:

Another pic–valve is on the lower pipe from the inducing fan.

Never seen one.

I have a carrier furnace with the intake from the outside and have a wood furnace in my home what happens when it gets real cold the cold air comes into the intake of the gas furnace turns into mousture in the fire box in my furnace and sits in a little cup shaped pan under the burner igniter and if you don’t keep a eye on it it will fill up and the igniter is in water

So they want to close the exhaust ?:shock: