Gas Cabinet Fireplace Install

[latitude45]

Im looking for some pointers on installing a direct vent gas cabinet fireplace using an existing fireplace for venting. From reading the manual and what I envision I plan on using a co-axial to co-linear connector to break the exhaust and combustion into 4" pipes. Extend the exhaust all the way up the chimney to a cap. My question is what to do with the combustion air pipe. Do I need to extend it up to the top of the chimney? Or can I have it draw air from inside the chimney space? I would put in a blockoff plate or stuff insulation in the chimney so the combustion air is drawn from the outside down the chimney. Sound like a plan?

 

[DAKSY]

Im looking for some pointers on installing a direct vent gas cabinet fireplace using an existing fireplace for venting. From reading the manual and what I envision I plan on using a co-axial to co-linear connector to break the exhaust and combustion into 4" pipes. Extend the exhaust all the way up the chimney to a cap. My question is what to do with the combustion air pipe. Do I need to extend it up to the top of the chimney? Or can I have it draw air from inside the chimney space? I would put in a blockoff plate or stuff insulation in the chimney so the combustion air is drawn from the outside down the chimney. Sound like a plan?

If you manual will allow the flexible vent, then you've almost got it right.
I believe you'll find the co-linear to co-axial adapter will bring you to a double 3" vent - NOT 4.
Run both to the top of the chimney & attach em both to the adapter & to the underside of the DV cap.
This way you can insulate around the liners TOP & BOTTOM.
You'll create a dead column of air in your chimney & your overall installation will be warmer.
That's how I'd do it.
YMMV

 

[latitude45]

yes sorry double 3” pipe.

The manual does say I can use flexible pipe but it wants me to use a specific brand.

As for insulating does it matter that it is an interior chimney?

 

[DAKSY]

Well, interior or exterior, the farther down you allow the cold air to come, the colder the chimney can be.
If you run the liners all the way up, & the kits generally allow for (2) 30 foot lengths, it's just as easy to
run em both down together (taped with aluminum tape at 6' intervals) as it is to run one down...
Just gotta ID the exhaust somehow so you attach it correctly to the adapter.

 

[jtp10181]

I think you should do whatever the manual says to do. The fireplaces we install are very clear on what options are allowed, and anything else is not. Full liners for both intake and exhaust gives the best results.

We need to know the model and a link to the manual. Otherwise its like asking how to fix a car without telling anyone what kind of car it is.

 

[latitude45]

its a napoleon GD25 built in 99. The manual however does not say anything about using an existing chimney. They give example of new construction and threw wall instillation. I will scan the doc and upload it tomorrow.

 

[jtp10181]

http://www.mikesheating.com/gf/gd25nap.htm

That's all I can find about it online. Not even on the MFG webpage anymore and they have no manual I can find.

That is a built in fireplace, NOT an insert. It is probably not approved or tested to install with a co-linear liner system. If you install it this way you void the UL listing, warranty, and probably your homeowners insurance policy. If it cannot be installed using the venting specified in the install manual, it should not be installed at all.

 

[latitude45]

Here is a link to part of the manual.

http://arc2earth1954390720.s3.amazonaws.com/pdf/gd25.pdf

 

[jtp10181]

Well they allow flexible coaxial pipe, but nothing about co-linear. Something else notably scary in the directions is that they recommend wrapping the vent in insulation if its going through an attic! .... this is just plain wrong and absurd. There is a reason the pipe mfg's have attic insulation SHIELDS, to keep the insulation AWAY from the pipe.

They also do mention that if you use Simpson pipe, to simply follow the Simpson instructions. That's almost seems to leave it open to using any Simpson product. I still can not recommend it, since I cannot physically see your situation