Random HVAC Question

[LTb1ow]

Pretty sure some folks on here are HVAC guys, so heres a question for ya.

I have a high efficiency furnace (PVC feed/return) in a closet that originally had an old furnace. So the closet has a big register on the floor that is direct to outside which I assume was to make sure old furnace had proper air flow.

I can theoretically block that vent off now, correct? HE furance should feed itself via the PVC ducting? There is nothing else in the closet.

[MDSheds_SS]

Most likely that register is for return air. Not a good idea to close it. The burner gets intake air from the PVC/outside. The actual air that gets heated and cooled is separate and has nothing to do with the PVC intake or exhaust. The more return air the better.

[LTb1ow]

Most likely that register is for return air. Not a good idea to close it. The burner gets intake air from the PVC/outside. The actual air that gets heated and cooled is separate and has nothing to do with the PVC intake or exhaust. The more return air the better.

Negative, this is literally a duct straight outside. Nice and drafty.

Furnace return for the closed system is different.

[MDSheds_SS]

Ok. Close it up then.

[LTb1ow]

Ok. Close it up then.

Thanks, figured as much but don't wanna gas myself

[The_Bishop]

Two separate PVC pipes going to outside, one for intake and the other exhaust?

Should be able to close that right up.

Forced hot air heat?

[LTb1ow]

Two separate PVC pipes going to outside, one for intake and the other exhaust?

Should be able to close that right up.

Forced hot air heat?

Yes and yes, and yes