Possible to Use B vent pipe for DV fireplace?

[Andyz89]

I currently have an existing wood burning fireplace in my home that the old owners had a gas insert installed. It’s ugly and I am looking to replace with a contemporary look fireplace. I removed the hearth and am building a pop out around the existing brick fireplace so I can tile from floor to ceiling.
My problem is the existing fireplace used B venting, just a single 4” vent to the top of the chimney.
I know the DV uses the 4x7venting to use the 4” as exhaust and the outer for air intake. I would have no problem replacing with new venting but the original cavity only has about 4” of clearance at one point, so I can’t fit the DV 7”venting at all.
So my question is, can I just hook up the existing 4” vent as the DV exhaust and just allow the incoming air to come from just above the DV fireplace?
I don’t want to do a traditional B vent insert because none have the contemporary look I am going for and the surrounds are meant for an existing hearth.

 

[Millbilly]

Some manufacturers may allow this with a block off plate. Have you not considered a b vent gas insert?

 

[DAKSY]

No. You MUST use DV pipe. There is no adapter approved to use both together.
Your exhaust must run to the cap. Your intake can be PARTIALLY installed up the
chimney, if the manufacturer approves that set up. Otherwise you need to run
Co-linear 3" flexible liners from top to bottom. There are some units on the market
which allow Direct Venting out through the masonry, with the cap attached to the
facing. You will need to decide on a unit & then see what the approved venting needs to be.
Every product manual will give you that info.

 

[Andyz89]

Some manufacturers may allow this with a block off plate. Have you not considered a b vent gas insert?

none of the B vent gas inserts have the contemporary look i want

 

[Andyz89]

No. You MUST use DV pipe. There is no adapter approved to use both together.
Your exhaust must run to the cap. Your intake can be PARTIALLY installed up the
chimney, if the manufacturer approves that set up. Otherwise you need to run
Co-linear 3" flexible liners from top to bottom. There are some units on the market
which allow Direct Venting out through the masonry, with the cap attached to the
facing. You will need to decide on a unit & then see what the approved venting needs to be.
Every product manual will give you that info.

I’m not looking to run both together. Just only the exhaust pipe all the way to the cap. And leave the intake open. The model I’m looking at is an Empire DVL33FP and I’ve read the entire manual and i don’t recall it saying anything but how to install it. My masonry opening has a metal piece used i believe to redirect the smoke fumes or whatever that I may be able to cut with a grinding wheel and make the opening wide enough to fit the 7” venting

 

[DAKSY]

The unit you want to install is NOT an insert.
Inserts are installed in existing fireplaces &
need to be vented with connections to the cap.
Yours is meant to be installed in a manufactured chase.,
Framed in. insulated & sheet rocked. You CANNOT install
it with B-vent. It is not tested to be installed utilizing that method.

APPROVED venting - From the install manual:

The following vent systems are acceptable for use with the DVL(25,33)FP series fireplaces:
Simpson Duravent® GS 4" - 6 ⅝", refer to page 23.
American Metal Products 4" - 6 ⅝" Selkirk Direct-Temp®
4" - 6 ⅝" Security Secure Vent® 4" - 6 ⅝" Excel DV Venting
Empire Flexvent Kit DVVK-4F
Empire Flexvent Kit DVVK-4FV

No B-Vent is approved.

 

[Andyz89]

The unit you want to install is NOT an insert.
Inserts are installed in existing fireplaces &
need to be vented with connections to the cap.
Yours is meant to be installed in a manufactured chase.,
Framed in. insulated & sheet rocked. You CANNOT install
it with B-vent. It is not tested to be installed utilizing that method.

APPROVED venting - From the install manual:

The following vent systems are acceptable for use with the DVL(25,33)FP series fireplaces:
Simpson Duravent® GS 4" - 6 ⅝", refer to page 23.
American Metal Products 4" - 6 ⅝" Selkirk Direct-Temp®
4" - 6 ⅝" Security Secure Vent® 4" - 6 ⅝" Excel DV Venting
Empire Flexvent Kit DVVK-4F
Empire Flexvent Kit DVVK-4FV

No B-Vent is approved.

I am going to be making a frame around the existing fireplace following the manufactures specifications which is why I chose this model rather than a traditional insert. Plus it offers 4 sided surrounds which the inserts are all 3 sided because they expect an existing hearth to be there

 

[Andyz89]

The unit you want to install is NOT an insert.
Inserts are installed in existing fireplaces &
need to be vented with connections to the cap.
Yours is meant to be installed in a manufactured chase.,
Framed in. insulated & sheet rocked. You CANNOT install
it with B-vent. It is not tested to be installed utilizing that method.

APPROVED venting - From the install manual:

The following vent systems are acceptable for use with the DVL(25,33)FP series fireplaces:
Simpson Duravent® GS 4" - 6 ⅝", refer to page 23.
American Metal Products 4" - 6 ⅝" Selkirk Direct-Temp®
4" - 6 ⅝" Security Secure Vent® 4" - 6 ⅝" Excel DV Venting
Empire Flexvent Kit DVVK-4F
Empire Flexvent Kit DVVK-4FV

No B-Vent is approved.

I’m just going to try to cut out a notch big enough to fit the proper venting

this pic is with the existing 4” vent you can see how it barely clear so I will try to cut the metal to make it 7”