www.desatech.com
108795-01N
9
INSTALLING TRANSITION PIPE AND
STARTER COLLAR
The transition pipe and starter collar shown in
Figure 9 are supplied with the fireplace, unattached
and ready for installation. Remove the starter collar
and set aside. Slide the transition pipe over the vent
collar and attach with a minimum of three screws.
Replace the starter collar over the transition pipe
and attach using four screws located on the leg
stands (five used on the model M42). To install
B-vent piping, slide the first piece of B-vent over
the transition pipe and attach with either a mini-
mum of two screws or other means approved by
the vent manufacturer.
Figure 9 - Installing Transition Pipe and
Starter Collar
B-Vent Piping
Transition Pipe
Starter Collar
Vent Collar
PRE-INSTALLATION
PREPARATION
Continued
VENTING INSTALLATION
A B-type venting system must be connected to the
appliance for venting to the outside of the building.
The following section is provided as a guide to a
standard B-type vent installation.
Standing codes requirements concerning B-type
vent installations may vary within your state,
province or local codes jurisdiction. Therefore,
it is recommended that you check with your
local building codes for specific requirements
or in absence of local codes, follow Section 7.0
of the current
National Fuel Gas Code ANSI
Z223.1/NFPA 54
and in Canada with
CAN/CGA
B149 for Category I systems using double wall
B-1 vent pipe
.
This gas appliance must be vented to the outdoors
only and may not be terminated into an attic space
or into a chimney flue servicing a solid-fuel burn-
ing appliance.
This appliance may be vented through a manufac-
tured chimney system or a masonry chimney using
a B-vent adapter or a chimney liner system if all
are listed, inspected and approved by local codes
and/or building authorities.
The examples shown in Figure 10, page 10 are
typical of most B-vent installations and codes
practices.
Example 1:
Shows the minimum allowable sys-
tem height and lateral offset for a 60° degree or
greater inclination. Code specifies that offsets at
60° degrees or greater are considered horizontal
and must follow the 75% percent rule for lateral
to total vertical system height. Codes also allows
only one offset in the total system when at 60°
degrees or greater. The total vertical height in this
example represents the minimum height of 8 feet
and therefore the allowable lateral is 6 feet when
the 75% percent rule applies. If the lateral length
must exceed 75% then the system must be sized in
accordance with the Category I venting tables.
Example 2:
Shows a multiple offset each at 45°
degrees of inclination. Multiple offsets are permit-
ted if they do not exceed 45° degrees of inclination.
The total lengths of the two offsets are not required
to meet the 75% percent allowable rule.
Example 3:
Shows a single offset at 45° degrees
of inclination and therefore the lateral length at
10 feet of offset does not have to meet the 75%
percent rule.
In each case the offsets must be supported and
firestops must be positioned wherever the vent
must pass through a sub-floor, ceiling joist or
an attic overhang. The vent pipe must terminate
vertically into a listed type vent cap and extend a
sufficient height through an approved roof flash-
ing, roof jack or a roof thimble. At all points the
listed clearances must be maintained.
Vent terminations must be located in accordance
with height and proximity rules of NFPA No. 54 or
CAN/CGA B149. These rules apply to vents at 12
in. diameter or less and require a minimum height
in accordance with the roof pitch and a minimum
of 8 ft. distance from a vertical wall or obstruction
(see Figure 11, page 10).
If venting horizontally through a side wall be-
comes necessary, a listed thimble approved for use
with B-type vent must be used. Check with your
local codes before venting through a side wall.
Some codes areas allow the use of existing B-type
vent systems if the system is at or above the recom-
mended diameter of the flue; in this case 6".
The flue connection must be made using listed
