Propane gas vent pipe questions

[mainecabin]

I have some questions about venting for a Jotul Allagash BV 300 propane stove. It requires a type B 4” vent pipe.

I am locating the stove where there used to be a wood stove with a 7” pipe which I have removed. The stove will go in a 1 story room. The B vent pipe will be vertical and it exceeds all safety clearances. There is a about a 10 foot run to get to the large, pre-existing, boxed in, double walled galvanized steel firewall (this extends another 3 feet or so above the firewall to the top of the old wood stove termination cap). The firewall has a 7” round opening in the firewall. The attached picture shows firewall/ cap.

Do I terminate the B vent pipe at the top of the firewall by getting various vertical B vent pipes and/ or adjustable length B vent pipe to exactly match the height from the top of the wood stove to the firewall? I would need to get a type B 4” adapter to connect to the existing 7” wood stove pipe. Would that adapter be specifically for a B vent installation?

The other option would be to run the B vent pipe inside the old stove pipe and extend it above the firewall as I could run the B vent pipe inside the old 7” diameter above the firewall as there is plenty of room.

Can I use the current termination cap (chimney cap) which was used for the wood stove? It appears to meet all specs in terms of clearances. Thanks.

 

[Riverbanks]

A picture of the the cap would help, but I like your idea of running it up thru the existing pipe

 

[mainecabin]

A picture of the the cap would help, but I like your idea of running it up thru the existing pipe

Here is a picture of the stove cap

 

[DAKSY]

What does the stove manual tell you about venting requirements?

 

[Riverbanks]

You got it made, just keep in mind, to not crowd the cap with the b-vent, flush or a bit higher with existing pipe , perfect

 

[mainecabin]

The stove manual does not address a scenario of using an existing vent cap for the B vent exhaust but I am within the limits of all other B vent safety guidelines

 

[Riverbanks]

What's somebody going to say,.. you are over protected.

 

[Lennox65]

The stove manual does not address a scenario of using an existing vent cap for the B vent exhaust but I am within the limits of all other B vent safety guidelines

The manual states that you must use a listed b vent termination cap.

 

[mainecabin]

Yes, you are right. I could put a B vent cap inside the cap you see in the picture. I didn’t think that would accomplish anything in terms of venting but maybe it is a good idea.