Harman P43 install - Will 2" outside air kit restrict flow at all or do I need to go with 3"

[Ocelot]

I'm replacing my old Englander EP25 with a 4 year old Harman P43 I picked up, yay!

My current outside air kit is 2" and as everyone here knows the Harman uses 2 3/8 flex tube. I have a 2 1/2" to 2" car exhaust adapter that fits nice and snug in the P43 air intake so if I use that, I can use the 2" flex pipe and it would be a clean and tight install.

I have to buy a new outside air kit anyway since the old one is damaged and was wondering if a 3" kit would be better than a 2" I'm not sure if the airflow would be much different between the 2" and the 3" but I think I would prefer the 2" unless the airflow from the 3" would be better.

Thoughts?

 

[Washed-Up]

I put a 3” on my P61A, any larger airflow is better...think of it as using a tiny straw vs using a larger straw in a drink

 

[Tonyray]

3" also for my P61A.

 

[bogieb]

The thimble of my P43 only has a hole for the 2" OAK, so that is what I use (connected to a 3" before it goes into the stove) . The stove runs fine. That being said, it is a very short run so YMMV.

My P61a has a 3" on it, which it definitely needs. Used to have a 2" and the 3" is a definite improvement. However, it has a much longer run (about 6') and the OAK is seperate from the thimble so I just had to cut a bigger hole in the plywood.

 

[Ocelot]

Thanks for the replies everyone.
My current outside air kit is basically straight out behind the stove so the total length is probably under 20 inches. It's also separate from the thimble so easy enough to make whatever size is needed.

 

[bogieb]

Thanks for the replies everyone.
My current outside air kit is basically straight out behind the stove so the total length is probably under 20 inches. It's also separate from the thimble so easy enough to make whatever size is needed.

Since it is separate, I would go with the 3".