Relining Masonry Chimneys for use with Gas Appliances. M&G Duravent 3GV60, 5GVAF, 4GVRRA4, 3GVFS, 4GV60F, 3GVIS, 3GVRS4, 3GVFF, 4GVRS, 4GVX8

system up towards the termination using

DuraVent Type B Gas Vent, connect a Male

Adaptor to the last section of the system, as shown in Figure 23 , insuring that the inner liner of the Adaptor fits smoothly inside the

Pipe or fitting below it. Push the Adaptor down as far as it will go, and tighten the locking bolt until the connection is snug.

RELINING MASONRY CHIMNEYS

FOR USE WITH GAS

APPLIANCES

1. Description.

A masonry chimney should be relined with B-Vent when venting a Category I gas appliance, such as a gas fireplace insert or freestanding gas stove, or to improve the venting and reduce condensation of existing gas appliances which are currently venting into the masonry chimney. These instructions encompass two general configurations: (1)

A gas fireplace situated inside an existing masonry fireplace (Figure 24) or (2), a freestanding gas appliance venting into an existing masonry chimney. (Figure 30)

2. Masonry Inspection.

Have the masonry chimney inspected by a CSIA Certified

Chimney Sweep or other qualified professional to determine it’s structural condition. Clean and repair as necessary.

3. Gas Fireplace. Carefully read the appliance manufacturer’s installation instructions. Use the recommended vent size.

Do not reduce the vent size below that of the flue exit on the appliance. Do not common vent gas fireplaces.

(a) Measurements.

Measure and record the dimension as shown on Figure 25 (Height “A”).

You will need an additional 15” of vent above the masonry chimney. It is a good idea to allow for a little extra height in your measurements.

(b) Pipe and Fitting Requirements. The bottom 5 foot section of vent will be Flex Pipe

Figure 22

EXISTING

SYSTEM

STORM COLLAR

WITH SCREWS

GAS FIREPLACE

B-VENT

ADAPTER

(FEMALE)

Figure 23

EXISTING

SYSTEM

FLASHING

B-VENT

ADAPTER

(MALE)

FLEX PIPE

Figure 24

(used to get around the smoke shelf, and to connect to the appliance). The remainder will be rigid B-Vent Pipe Sections. For each pipe joint, subtract 1-1/2 inches.

(c). Connector.

Read the appliance manufacturer’s instructions for connecting the Flex Pipe to the appliance. In most cases, a Draft Hood Connector will be required as shown in Figure 26 . If you are not sure, contact

13

14

C

B

15 INCHES

A

Figure 25

DRAFT HOOD

CONNECTOR

Figure 26 the appliance manufacturer for clarification.

Place the appliance out in front of the fireplace area, as shown in Figure 27 , and install the

Draft Hood Connector, or other device in accordance with the appliance instructions.

The Flex Pipe Coupling may be able to attach directly to the appliance.

(d). Flex Pipe Assembly. Assemble first Rigid

Pipe Section to the Flex Pipe, insuring that the

“UP” arrows are in fact, pointing up. Push the sections together and twist to lock. Screws are not required, however if you desire to use them, use #8 sheet metal screws 1/4-inch long, being careful to not penetrate the inner liner. Repeat this process for the remainder of the Pipe

Sections, and lower the assembly down the chimney. Lower it below it’s normal position as shown in Figure 28 .

(e). Position and Connect Fireplace.

Push the gas fireplace towards the firebox, and connect the Flex Pipe female coupling to the appliance, or to the appropriate connector as specified by the appliance manufacturer. If insufficient space is available between the top of the appliance, and the fireplace opening, an access opening in the opposite side of the masonry chimney may be necessary. Position the gas appliance on it’s final location, again complying with the manufacturer’s instructions in regards to location. Install any shields or covers at this time.

(f). Adjust Height. Go to the top of the chimney and pull the vent system up to its desired height.

In most cases, this will be 15 inches above the masonry surface. Make a mark on the

Pipe Section even with the top of the masonry surface. If the top of the pipe is near a steep roof (more than 7/12 pitch) ,use the height as stated in Table 2 .

(g). Flashing. Bend and trim the base of the

Tall Cone Flashing so it fits onto the top of the masonry chimney. Use masonry anchors and

non-hardening sealant to secure the flashing to the masonry (Figure 28).

(h). Storm Collar. Slide the Storm Collar over the pipe down to top of the Flashing. Secure the

Storm Collar in place with at least (3) 1/4” sheet metal screws (Figure 29) . Do not penetrate the inner liner. The Storm Collar and Flashing will support the weight of the vent assembly. Use non-hardening sealant around the top of Storm

Collar to make a weatherproof seal.

(i). Termination Cap.

Install the Termination

Cap as shown in Figure 28 . This concludes the procedures for installing a gas fireplace in an existing masonry fireplace. Conduct a final inspection of the system, and verify that you have complied with the manufacturer’s installation instructions.

4. Gas Appliance Venting Into the Side Wall of a Masonry Chimney.

(a). Locate Appliance.

Set the appliance in it’s desired position, and mark the center of the hole where the lateral Pipe Section is to pierce the masonry chimney. Ensure the manufacturer’s requirements have been followed, particularly in regards to distances from combustible surfaces. Refer to Figure 30 .

(b). Hole in Masonry. Move the appliance aside, and break out the masonry, forming a hole large enough for the Pipe Section to get through, and also large enough to reach through and hold the Tee, while connecting the horizontal Pipe Section. An alternate procedure is to make the hole only large enough for the Pipe Section to pass through, and construct an access gate on the other side of the masonry chimney. Do not mortar directly to the pipe, but use a Mortar

Sleeve instead.

NON-

HARDENING

SEALANT

B-VENT PIPE

SECTION

STORM COLLAR

TALL CONE FLASHING

MASONRY

ANCHORS

NON-HARDENING

SEALANT

Figure 28

USE (3)¼" SCREWS. DO NOT

PENETRATE INNER WALL

SCREWS

Figure 27

SIDE VIEW

Figure 29

TOP VIEW

15

16

STORM COLLAR

WITH SCREWS

TEE

OPTIONAL

HIGH WIND

CAP

FLASHING

TRIM COLLAR

DRAFT HOOD

CONNECTOR (IF

REQUIRED)

GAS

APPLIANCE

Figure 30

Figure 31

CERAMIC FIBER

INSULATION

(c). Tee. A Tee is installed at the bottom end of the assembled vertical Pipe Sections, as shown in Figure 30 . The Tee has a removable

Tee Cap at the bottom, for cleaning and condensate removal. If the configuration of the building permits it, a clean-out access gate is recommended.

(d). Vertical Pipe Sections . Run the assembled vertical Pipe Sections (with the Tee attached to the bottom), down the chimney, until the horizontal branch of the Tee is opposite the hole in the masonry.

(e). Adjust Height.

Hold the assembled Pipe

Sections in this position, and make a mark even with the top surface of the masonry chimney. The vertical Pipe Sections should protrude 12 inches (in most cases) above this mark. If the top of the pipe will be near a steep roof (more than 7/12 pitch), use the height as stated in Table 2 .

(f). Flashing. Bend and trim the base of the

Tall Cone Flashing so it fits onto the top of the masonry chimney. Use masonry anchors and non-hardening sealant to secure the flashing to the masonry (Figure 28).

(g). Storm Collar. Slide the Storm Collar over the pipe down to top of the Flashing. Secure the Storm Collar in place with at least (3)

1/4” sheet metal screws (Figure 29) . Do not penetrate the inner liner. The Storm Collar and

Flashing will support the weight of the vent assembly. Use non-hardening sealant around the top of Storm Collar to make a weatherproof seal.

(h). Horizontal Pipe Section(s).

Run the horizontal Pipe Section(s) through the hole in the masonry, and connect it firmly to the

Tee, either by reaching through the hole, and holding the Tee while twisting the Pipe Section, or by holding the Tee through the access door while someone twist-locks the Pipe Section to it. Use an Adjustable Pipe Length as needed