Installation and Service Manual

6
6-584.13
Model HDS/HDC unit heaters must be vented with the proper
passageway as described in these instructions to convey
flue gases from the unit or the vent connector to the outside
atmosphere. The heaters must also have a separate combustion
air intake pipe to bring in fresh air for combustion from the
outside atmosphere.
The venting instructions are organized in sections, based on
installation type. The sections are identified as follows:
Instructions Applicable Installation Instructions
Section by Vent System Type
A General instructions for ALL installations
B VERTICAL 2-PIPE vent systems j
C HORIZONTAL 2-PIPE vent systems j
D HORIZONTAL AND VERTICAL
CONCENTRIC vent systems j
j The differences between vertical and horizontal vent systems in 2-Pipe or
concentric vent configurations will be identified in “Section A - General
Instructions – All Units”.
Section A – General Instructions – All Units
A1. If the unit heater being installed is replacing existing
equipment and using the existing vent system from that
equipment, inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel Gas Code
ANSI Z223.1 or CSA B149.1 Installation Code-latest edition
and these instructions. Determine that there is no blockage
or restriction, leakage, corrosion and other deficiencies,
which could cause an unsafe condition.
A2. The combustion air pipe and vent pipe should be galvanized
steel or other suitable corrosion resistant material. Follow
the National Fuel Gas Code for minimum thickness of vent
material. The minimum thickness for connectors varies
depending on the pipe diameter. Do not vent unit with PVC
or other forms of plastic venting material.
A3. All heaters come with factory installed vent and combustion
air adapters for attaching the vent pipe to the heater. Attach
the vent pipe to the adapter with 3 corrosion resistant
screws. (Drill pilot holes through the vent pipe and adapter
prior to screwing in place). Vent pipe must not be smaller
than the connector size.
A4. Refer to Table 6.1 for total equivalent vent pipe lengths,
making the vent system as straight as possible. The
equivalent length of a 3” elbow is 1’ and for a 4” elbow is 5’.
A5. A minimum of 12" straight pipe is recommended from the
flue outlet before turns in the vent pipe.
A6. Horizontal sections of vent pipe are to be installed with an
upward or downward slope from the appliance of 1/4" per
foot and suspended securely from overhead structures at
points not greater than 3' apart.
A7. Fasten individual lengths of vent together with at least 3
corrosion-resistant sheet metal screws.
A8. Keep single wall vent pipe at least 6" from combustible
materials. For double wall vent pipe, follow the vent
pipe manufacturer’s clearances to combustibles. The
minimum distance from combustible materials is based
on the combustible material surface not exceeding 160°F.
Clearance from the vent pipe (or the top of the unit) may be
required to be greater than 6" if heat damage other than fire
could result (such as material distortion or discoloration).
A9. Avoid venting through unheated space when possible.
When venting does pass through an unheated space or
if the unit is installed in an environment that promotes
condensation, insulate runs greater than 5' to minimize
condensation. Inspect for leakage prior to insulating and use
insulation that is noncombustible with a rating of not less
than 400°F. Install a tee fitting at the low point of the vent
system and provide a drip leg with a clean out cap as shown
in Figure 8.1.
INSTALLATION - VENTING
WARNING
1. Gas fired heating equipment must be vented - do not
operate unvented.
2. A built-in power exhauster is provided - additional external
power exhausters are not required or permitted.
3. If an existing heater is being replaced, it may be necessary
to resize the venting systems. Improperly sized venting
systems can result in vent gas leakage or the formation of
condensate. Refer to the National Fuel Gas Code ANSI
Z223.1 (NFPA 54) or CSA-B149.1 Installation Code - latest
edition. Failure to follow these instructions can result in
serious injury or death.
4. Under no circumstances should 2 sections of double wall
vent pipe be joined together within 1 horizontal vent system
due to the inability to verify complete seal of inner pipes.
CAUTION
Installation must conform with local building codes or in the
absence of local codes, with Part 7, Venting of Equipment, of
the National Fuel Gas Code, ANSI Z223.1 (NFPA 54) - latest
edition. In Canada installation must be in accordance with
CSA B149.1.
Figure 6.1 - Venting Through Combustible Roof or Wall
Flashing
Listed
Thimble
Listed
Terminal
Listed
Terminal
Flashing
Clearance Specified
by Type B Vent Mfg.
Listed
Thimble
Single Wall Vent Pipe
Double Wall Vent Pipe j
Single Wall Vent Pipe Terminating
with Double wall vent pipe. j
Single Wall Vent Pipe
j See Instruction A12 for attaching single wall pipe to double wall pipe.
Double
Wall
Single
Wall
Listed
Terminal
Clearance Specified
by Type B Vent Mfg.
Single
Wall
Listed
Terminal
Table 6.1 - Vent Pipe Diameters, Transitions, and
Total Equivalent Vent Pipe Lengths For Horizontal
and Vertical Venting Systems
Model
Size
Vent Pipe
Sizes
Minimum
Eqv. Length
Maximum
Eqv. Length
30-45 3" 3' 25'
60-125 4" 3' 25'