Mr Heater vent up or down?

[martymet]

Just installed the Mr Heater 75 and the instructions state that the vent should be sloped upward through the wall thimble. There are several posts here that say it should be sloped downward ( this is a horizonal vent). I can understand the rationale for both, but which is right?
Also, the gap between the thimble and the vent pipe should no be sealed in any way, is that right?

Thanks guys.

 

[scottr]

Just installed the Mr Heater 75 and the instructions state that the vent should be sloped upward through the wall thimble. There are several posts here that say it should be sloped downward ( this is a horizonal vent). I can understand the rationale for both, but which is right?
Also, the gap between the thimble and the vent pipe should no be sealed in any way, is that right?

Thanks guys.

It may be code related. Here in St. Paul, Minnesota my inspector wanted all horizontal vent pipes pitched UP the usual 1/4-in per foot minimum. No downward pitched horizontal runs. I believe the only advantage to the downward option is if there was some clearance issue that forced you to need to pitch downwards. Otherwards, because you want to encourage the flow of gases outside, upwards pitch is natural!

You are correct. nothing should be placed in the gap between the pipe and thimble.

Scott

 

[MXtras]

UP.

Who said to pitch it down?

Scott

 

[martymet]

I have been reading the other threads on this board relating to the same type of question, and there are a few references to the downward slope. Glad I asked, but more glad I got it right.
Thanks again

 

[mulepackin]

The install manual for my HD75, shows both up and down pitch configurations, both with specific drops, need for drip leg in the up pitch etc. They are power exhausted, otherwise the natural flow of combustion byproducts would be a huge factor.

 

[GearHd6]

I believe the horizontally vented units are supposed to be pitched down so any condensation can run out the end. Unless you got a vent kit thats got a drain hose back near the heater so the condensation can drain out the hose and not the exhaust end. Read all your instructions very close and read the vent kits instructions. Mines pitched 1/4" per foot down so it drains out the end. You dont want condensation draining back into your heater.