16
MASON-LITE Chimney Systems:
This MGFPST43(P)A Mason-Lite Fireplace requires the
installation of a Vent Plate Assembly which allows connection
to either a 12 inch diameter B-Vent system or UL 103-12
Class A Chimney system.
Installers are cautioned to put the chimney system together
exactly as instructed and shown in chimney manufacturer’s
guide. Any variations may have serious consequences
resulting in an accident or malfunction. If instructions are not
followed, the warranty on the product will become null and
void.
Note that although the fireplace itself is a “zero clearance”
fireplace, the most important aspect of the installation is
maintaining the minimum required clearances to combustible
materials for the flue system according to the chimney pipe
manufacturer’s recommendations, otherwise a potential fire
hazard may occur.
Warning: do not interchange chimney manufacturer’s parts
with any other parts except those specifically required by
the chimney manufacturer’s recommendations otherwise a
potential hazardous condition may be created.
A “B-type” venting system must be connected to the appliance
for venting to outside of 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 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 burning appliance.
Assuming you have sections of vertical pipe that are more than
10’ (ten feet) measuring between elbows, you must insert – at
midpoint – a chimney stabilizer. When installing the stabilizer,
pull out the support straps with a good amount of tension and
hammer to the frame.
This appliance may be vented through a manufactured
chimney system or a masonry chimney using a B-vent adapter
or a chimney liner system if the system is listed, inspected and
approved by local codes and/or building authorities.
The examples shown in Fig.28 are typical of most B-vent
installations and codes practices.
Example 1:
Shows the minimum allowable system height and lateral offset
for an inclination of 60° or greater. Code specifies that offsets
of 60° or greater are considered horizontal and must follow
the 75% rule for lateral to total vertical system height. Codes
also allow only one offset in the total system when at 60° or
greater. The total vertical height in this example represents the
minimum height of 8 ft. and therefore the allowable lateral is 6
ft. when the 75% 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 a 45° inclination. Multiple
offsets are permitted if they do not exceed a 45° inclination.
The total lengths of the two offsets are not required to meet
the 75% allowable rule.
Example 3:
Shows a single offset at 45° of inclination and therefore the
lateral length at 10 ft. of offset does not have to meet the 75%
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 flashing, 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. These rules
Figure 28
