Prefab Fireplace Blues

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hoot

Member
Jan 6, 2012
63
Ben Wheeler, TX
Hello all.
We just moved from PA to Texas. The home we purchased has a stunning stone fireplace but unfortunately they elected to have a Superior prefab firebox installed. It had the outside air kit installed and a black iron stubout with the gas valve installed out on the side of the stonework. That was for a log lighter that was never installed. I have since installed the log lighter. The key would not go over the square valve stem due to the mason not lining up the estuchen and a bunch of cement around the stem. I got the estuchen out, chipped away the excess cement and was able to easily get the key in. The valve was fully open! I already knew because I was removing the capped end and gas started coming out so I just retightened it. Crazy what you run into.

This was our first winter here. We don't get the long winters but when it gets cold we like a fire. Up north in PA a couple of years we burned 24/7 all winter. That was work.

And so I lit the first fires and immediately realized the smell. It's a straight up flue probably 12 ft to the top. Flue wide open, left side there is a lever you pull out for outside combustion air. I am unable to figure out where this outside air actually enters the firebox. We've also had the patio door cracked. What we seem to be experiencing is poor draft due to not really cold conditions. Our place in PA were sealed burners so you didn't have the issue. Smoke had only one place to go. This unit sometimes smokes the room up.

Bottom line, after experiencing this cheap box, I'm annoyed with it's performance. And those horrible screens that you have to shake and jimmy to open and close. They've been around as long as I remember... never improved. But most importantly, I'm not interested in an open fireplace. Now it's time to figure out how to safely install a high quality insert.

So these prefab units are installed into wood framing. The unit isn't real heavy so the framing is not real robust.
Also, they install the unit into the framework before doing the stonework which basically locks the unit in. I have seen videos of them being removed by cutting the outside wall and pulling it out from outside. In my case the outside wall is another room so yes that is a possibility.
I also have the idea of attacking it from the inside. Remove all removable parts, pull the chimney from above if possible. I don't know if it's secured on the way up anywhere. I think the flue is the tough part... how it's connected, is it secured on the way up, will it drop. Those things go through my head. Then use a metal cutting disc and cut it out in pieces.

So I'm here for suggestions and looking if others have done this. After it's out I'm thinking of retaining the original flue, it's 8", and running a 6" double wall insulated liner up there. Down in the cavity where the old box was. do a buildout to match an insert's requirements for clearances to combustable materials and such as well as weight support. Might use combination of cement board and rockwool.

What do you all think?

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Last edited:

DAKSY

Full Time RVer
Staff member
Dec 2, 2008
9,359
Wherever we're parked
Have you considered a GAS insert? You already have the gas line in the firebox,
& the colinear liners should fit down the existing ZC pipe. Surrounds can be modified
to fit exactly into the opening between the insert& the ZC box. A whole lot cleaner &
more efficient than your current set up.
 

hoot

Member
Jan 6, 2012
63
Ben Wheeler, TX
Have you considered a GAS insert? You already have the gas line in the firebox,
& the colinear liners should fit down the existing ZC pipe. Surrounds can be modified
to fit exactly into the opening between the insert& the ZC box. A whole lot cleaner &
more efficient than your current set up.
I'm a wood burner at heart and love the newer sealed units. I don't like being dependent on big oil either, not that down here it's as critical.
 

hoot

Member
Jan 6, 2012
63
Ben Wheeler, TX
I think you will have to look up your model of superior also to make sure that model qualifies.
The Superior manual states:
Do not install a fireplace insert in this fireplace unless the manufacturer's instructions with the insert specifically state this fireplace has been tested for use with this insert.

Crossing my fingers,
 

SpaceBus

Minister of Fire
Nov 18, 2018
6,883
Downeast Maine
Wow, what an easy way to resolve your issue. A flue for that Lopi insert should even fit down the existing stainless flue making for a fairly painless install.
 

hoot

Member
Jan 6, 2012
63
Ben Wheeler, TX
Wow, what an easy way to resolve your issue. A flue for that Lopi insert should even fit down the existing stainless flue making for a fairly painless install.
Yea I installed a liner years ago for a Hearthstone Clydesdale years ago into a masonry chimney. It wasn't that difficult and that house also was only one story which makes everything easier.