Harman p35i: How to connect existing outside air intake vent on firebox floor to pellet stove?

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drp37

New Member
Nov 3, 2021
12
Georgetown, ON, Canada
Hi, I'm about to purchase a Harman p35i. I requested my dealer include an OAK for the installation. They noted that I have an existing outside air intake vent on the bottom of the firebox floor, which is true, but they didn't explain what they were planning on doing with it to satisfy my OAK request...I am waiting for them to clarify.

My question is, how will they make a connection to this vent if the outside air connection on the p35i is at the back of the unit and the unit will be sitting on the firebox floor covering this vent?
 

Washed-Up

Minister of Fire
Nov 5, 2011
804
Kananaskis,Alberta, Canada
It would have to line up perfectly, some photos would help
 

drp37

New Member
Nov 3, 2021
12
Georgetown, ON, Canada
Yes, pictures would probably help!

The 0 mark of the tape measure is where the surround would start. In the top view of the pellet stove, the item marked in yellow is the outside air connection.

222.jpg



111.jpg
 

Washed-Up

Minister of Fire
Nov 5, 2011
804
Kananaskis,Alberta, Canada
They might be able to use it, but not without modifying the Pelletstove base….if that’s possible
 

Dataman

Minister of Fire
Sep 10, 2018
1,013
Newport, Wa
Talk to place that does sheet metal and have them fab it for you. Then use flexible pipe. Use stub on stove end so the soft alum pipe does not get damaged. 1st pic is what I used for my Harmon XXV and 2nd pic is out of Manual for your stove. It's setup for same type of flex tubing. You won't need stub I bet since it's part of kit. Sheet metal shop will have to build your air kit for the floor vent. You can fab out of Cardboard I bet for prototype. Personally I would have local sheet metal place fab part from stove to flex tube also. I bet lots cheaper. 300 bucks seems steep

IMG_20210119_064841867.jpg Untitled-1.jpg
 
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drp37

New Member
Nov 3, 2021
12
Georgetown, ON, Canada
Dealer/installer responded via email by saying that "the mounting bracket will hold the unit up to allow access to the outside air".

I still don't get what they plan on doing. The clearance between firebox floor and bottom of unit (when in final position) is probably <1"...how will they duct it?
 

drp37

New Member
Nov 3, 2021
12
Georgetown, ON, Canada
Waiting for a callback from the dealer/installer, one of their installers will be describing their approach, but I strongly suspect they will not be ducting as there is no physical clearance. I think I will just seal off the firebox vent and force them to use a ducted 100% outside air option as per Figure 4.1 in the Harman installation manual.

Any suggestions on creating a non-permanent seal in the firebox vent? Would simply stuffing 6" Roxul insulation in the vent ducting from the outside intake work?

Screenshot 2021-11-24 172639.jpg


UPDATE: Spoke with installer, he noted the following:

1) Canadian code does not allow installation of outside air intake as per Figure 4.1 above (ie in chimney flue).
2) The colder and humid Canadian winters (at least in Ontario) increase likelihood of condensation in ducting and unit. He noted that an Italian stove manufacturer (I can’t remember who he quoted) in their installation manual, recommends against direct cold air intake for Canadian installs.

So I guess I will have to use the firebox vent as is.
 
Last edited:

Mt Bob

Minister of Fire
Oct 31, 2013
3,365
park county montana
You are being mislead. That link is all about -"For heating appliances burning solid fuel and operating on natural draft," which a pellet stove is not, they are forced draft. Many thousands use the vent system shown in you picture above, in very cold climates,also.
If you want a definite answer for your area,contact a WETT inspector.
 

drp37

New Member
Nov 3, 2021
12
Georgetown, ON, Canada
You are being mislead. That link is all about -"For heating appliances burning solid fuel and operating on natural draft," which a pellet stove is not, they are forced draft. Many thousands use the vent system shown in you picture above, in very cold climates,also.
If you want a definite answer for your area,contact a WETT inspector.
The link I added was not meant to describe my situation, rather, was something evidence based data that I came across.

The installer I am dealing with is WETT certified and provided feedback as I noted above.