Harman p61 Exhaust Install

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New Member
Dec 4, 2023
Planning out my install and after looking at the user manual, there are clearly different options when it comes to installing the exhaust piping. I'm leaning towards doing the straight shot out from behind the stove to the outside. What are the negatives of doing it this way? I saw some mentioning about smoke coming into the house if there are power outages. Is this true? Any other negatives? Thanks!
Harman recommends a vertical rise in the exhaust venting of 3-5 feet to help with natural draft if the stove loses power.
If I were to do mine again, I’d go T off the appliance adapter straight up to about 18” from my 8’ ceiling and out, by doing it that way I wouldn’t have had to modify everything when I switched to my P61A as my old stove was higher exhaust and I did go straight out.
My P61a has a vertical rise of 6-7' inside. Vertical is a bit of a misnomer as the stove sits about 5' to the side of the old basement window that it is vented thru so it is at an angel. I have never had it puff smoke out into the basement at a power outage.

The P43 is basically a straight shot out the wall (although not exactly since I had to do some finagling to match the hole from when I had another brand stove there. I did test it and I got just a bit of smoke. Not too much, but smoke will find the weakest point and filter thru that so if a door gasket has a corner going, it will find it.

My advice is to use a UPS that will allow the stove to gracefully shut down (hey, you really want a UPS anyway to clean u dirty electricity and take care of spikes). The right UPS will take over when the power goes out and the stove will sense this from the sine wave (I think that is what it senses), quit feeding and pulse the exhaust fan for something like 10-15 minutes to keep the smoke evacuating where it should. In that time, you can get a generator going, or just let the stove complete its shut down until the power comes back without any worries about smoke.

BUT, you have to make sure it is the "right" type of UPS (not pure sine wave) and some of the newer Harman stoves you have to set a dip switch (so I've heard anyway). I started using APC BE750G (what was recommended by the manual back in the early teens. That model has been discontinued, but I just replaced the batteries with the BE850G2 batteries and they work the same way.
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