Fresh air intake damper

vpchester

New Member
Oct 5, 2020
15
Washington
I'm installing a 4 inch fresh air flexible duct. Would like to install an airtight damper that will allow me to close the intake air from entering the stove when not in use. I don't want to pay the $170 for the ones the stove retailers advertise. Has anyone found a simple low cost solution? For example, just use a 4 inch pvc ball/gate valve, or some other ingenious DIY solution? Thanks!
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,788
South Puget Sound, WA
Yes, a simple butterfly damper for 4" duct will work, but it will be leaky. It's more of a volume damper.

4" pvc ball valves aren't cheap. A 4" pvc irrigation valve might be a little less expensive.
 

vpchester

New Member
Oct 5, 2020
15
Washington
I found on Amazon this 4 inch "self cleaning no clog aluminum blast gate cut off valve for dust collection systems" (only $13.99!). Anyone have other homemade devices?

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Woodcutter Tom

New Member
Apr 28, 2019
63
Northern Illinois

vpchester

New Member
Oct 5, 2020
15
Washington
A couple final questions:
1. I've read that for the fresh air intake, one should minimize the number of 90 degree bends?? My Drolet 1800i insert's air intake is on the side, so it forces me to have two 90 degree bends in my 4" aluminum flex liner (total run of about 5 ft to outside of house).
2. I'm planning to use semi-rigid aluminum flex dryer ducting. Instead, can I use 4" flex dryer ducting that is foil wrapped (easier to flex) or will it melt close to the insert?
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,788
South Puget Sound, WA
The 2 elbows and the aluminum duct will be ok. That area of the stove does not get nearly hot enough for this to be an issue.
 

vpchester

New Member
Oct 5, 2020
15
Washington
Apologies for more questions...

I started installation today and removed an old gas insert. I see that the masonry fireplace has an ash door that opens to the crawl space under the house. Can I use this to run my 4 inch fresh air intake? Simply, insert the flexible ducting into the ash door and run it into the crawl space? I plan to go under the house tomorrow to make sure there are no obstructions. The crawl space has several air vents so I would assume this would be adequate for fresh air into the insert. Anything I should be on the lookout for to avoid? This option would really be a time and effort saver since I was planning to bore through the side of the fireplace and house to run the fresh air ducting.

Also, how does one remove the insert door? I'm trying to lighten it up so it will be easier to move around.
 

Highbeam

Minister of Fire
Dec 28, 2006
17,868
Mt. Rainier Foothills, WA
I live in Washington and my fresh air intake draws air from the ventilated crawlspace under my home. Works great. You’re not using that ash dump anymore.
 

snaple4

Feeling the Heat
Dec 18, 2017
272
AR
Lots of people use the ash dump for makeup air. I don't see a problem as long as you have fresh air going into it. You may have to remove the door outside and install a screen.

Also, if you are worried about the bends just use some metal 90 degree elbows. They are cheap and the airflow they allow are significant compared to a flexible elbow.