Blockoff Plate Necessary?

[tynman]

Below is a pic of my prefab zero clearance before my stove install. I have a Hearth Heater that is vented from the back with a tee attached to a liner going right up the opening you see in the pic. There is insulation in the small gap between the pipe/liner and the prefab opening. I'm not having any problems heating our home with this stove, but I've been reading alot about the benefits of a blockoff plate. Just not sure how much I'd benefit (if at all) from putting one in since it seems as though the top of my prefab looks to be acting like a blockoff plate (though it's not insulated).

Any thoughts?

 

[DAKSY]

In that install, you hafta insulate the SS flex liner with
a wrap which will pretty much block off any air flow in or out.
No block-off plate needed.

 

[tynman]

Thanks DAKSY, it is an insulated the SS flex liner.

 

[DAKSY]

Thanks DAKSY, it is an insulated the SS flex liner.

You need to insulate the liner because of the heated gases flowing
thru it that are generated by your Hearth Heater.
The existing ZC vent has a 2" Clearance to Combustibles (CTC) which is NOT enough
to safely vent your liner. That single-wall liner has an 18" CTC & could potentially
ignite any framing members within that 2" clearance...
Better safe than....