How to Convert B-Vent to Direct Vent

in Fireplace Product Feature by Alan Gleave

Converting B-vent to Direct Vent

A full refit of a gas fireplace vent run isn’t always a viable option. This can be due to HOA/Strata restrictions or juridical code requirements. Additionally, condominiums are rightfully apprehensive about anyone opening up walls to replace a venting run. Fortunately, B-vent to direct vent conversion kits exist.

Now available for the DelRay linear and Square series, you can replace a dated gas fireplace with a modern unit without replacing the entire vent run. Not all DelRay models are compatible with the conversion kit, so be sure to confirm in the BVK35 Conversion Kit Manual.

The B-vent to direct vent conversion kit allows the current vent run to remain in place while having minimum impact on the building itself. As an added benefit, the new roof termination is often visually accurate to the previous B-vent termination. Therefore, the exterior of the building also retains a similar aesthetic.

The B-vent to Direct Vent Conversion Process

As with any gas fireplace project, review the fireplace manual, confirm clearances, and make sure to check local codes before starting any work. This is a basic overview of the conversion process. Please consult the conversion kit manual for full step-by-step instructions and a list of parts/tools required.

B-vent to direct vent conversion kit

Current Fireplace & Termination

This conversion is for 5″ B-vent fireplaces with a straight vertical vent run.

Before removing anything, cut the B-vent to prevent damaging the vent and supports.

Remove the Fireplace & Termination

Remove the termination and B-vented fireplace. Do not remove or damage the existing B-vent run, as this will become the outer wall of the new direct vent system.

Use an inspection camera to help verify the integrity of the existing vent and feasibility of the installation.

Insert the Liner

Lower a 3″ aluminum liner down the B-vent run to create a coaxial vent system. Fasten the 3″ liner to the collar on the lower adapter (BVA25) using sheet metal screws.

Add the Adaptors

First, connect a BVA35 adapter to the top end of the 3″ liner and attach to the 46DVA-VCH termination.

At the fireplace end, a  use a 46DVA-AD-M1 to convert the Montigo 4/7 venting to Duravent 4/7.

Then use a BVA35 to connect to the B-vent adaptor. A DRSQCOL47 reducing collar will be required as well if installing a DelRay DRSQ38.

Add the New Termination & Fireplace

At this point, seal all inner joints with Mill-Pack and outer joints with aluminum foil tape.

Other Considerations

  • Confirm the existing venting uses dual wall pipe, not single wall pipe
  • This kit is only applicable with DelRay Linear 36/48/60, and DelRay Square 34/38 fireplaces
  • Use an inspection camera to verify the integrity of the vent and feasibility of the installation
  • Where required, extend the existing B-vent to the adapter location using flex or rigid 4/7 Direct-vent
  • Duravent termination is not included in the conversion kit and must be ordered separately

To convert your B-vent to direct vent, contact your local Montigo dealer to enquire about the BVK35 Direct-Vent Adapter Kit

BVK35 Kit Manual


Commercial Quality

Professionals planning a custom residential or commercial fireplace project, please contact the Montigo Sales Rep in your area.