Garage Heater, Thimble w/Heat Diffuser?

[JZB]

Hi all,
Recently moved into a new build and the gas/electrical/thermostat wiring was already roughed in. I plan to install a ~50k BTU garage heater, but I'm working through measuring for venting. The garage already has a "thimble" of sorts installed, but it's not the type I've used in the past and looks like it would not have anything sticking further to the exterior. Has anyone used a similar setup before, and if so does the entirety of the 3' vent pipe just need to be inside then? Just looking to see if anyone else has seen/used/installed something similar. It will frequently get below zero here in the winter (Montana) so trying to get things buttoned up and heated/insulated before snow gets here. Thanks!

 

[rlitman]

Looks like a co-axial vent to me. The inner tube is the exhaust, and the larger circle is the fresh air intake.

 

[PoorUB]

Looks like a gas fire place vent to me. I have never seen a shop heater vent like that, and I used to sell ans service them.

 

[JZB]

After some detective work, I've figured out that what I have is a "Tjernlund VH1-4", which seems to be a multi-purpose vent. The manual says it's cleared for systems up to 575F, which I would imagine is well within the range of a typical garage heater so I guess I'll give it a shot.

Tjernlund VH1-4

 

[Fav Onefour]

After some detective work, I've figured out that what I have is a "Tjernlund VH1-4", which seems to be a multi-purpose vent. The manual says it's cleared for systems up to 575F, which I would imagine is well within the range of a typical garage heater so I guess I'll give it a shot.

Tjernlund VH1-4

I'd verify that it's cleared for a 50,000 btu unit.
It's nice that the vent is installed. I'm not sure that the location and style will work for your plan. That thing is awful close to and under the soffits.