Table of Contents
Advertisement
926SA: Installation, Start-up, Operating, Service and Maintenance Instructions
6. When using polypropylene venting systems with flexible vent
pipes, perform adjustments for the equivalent length of the flexible
vent pipe to the calculated total equivalent venting system length.
See the polypropylene vent system manufacturer's instructions for
details.
7. Select a diameter of vent pipe from
Maximum Equivalent Vent Length (MEVL) shown for that
application for that specific furnace input size. Compare the Total
Equivalent Vent Length (TEVL) to the MEVL:
8. If the Total Equivalent Vent Length is shorter than the Maximum
Equivalent Vent Length for the diameter of pipe chosen, then that
diameter of pipe selected may be used.
9. If the Total Vent Length is longer than the Maximum Equivalent
Vent Length for the diameter of pipe chosen, that diameter pipe
MAY NOT be used for venting the furnace. Try the next larger
.
diameter pipe
NOTE: If the calculated Total Equivalent Vent Lengths results in
different diameter pipes for the vent and combustion air, select the larger
diameter for both pipes.
NOTE: If the Maximum Vent Length for diameter of the pipe selected is
longer than the measured length and the equivalent length of all the
fittings and terminations (TEVL), recalculate Total Equivalent Vent
Length using the next smaller diameter. If the Maximum Equivalent
Vent Length is still longer than the longer TEVL of the vent pipe or
combustion air pipe, then that diameter of pipe selected may be used.
When installing vent systems pipe lengths of 10 ft. (3 M) or less, use the
smallest allowable pipe diameter. Using a pipe size greater than required
for short venting systems may result in loss of efficiency, incomplete
combustion, flame disturbance, or flame sense lockout.
For vent systems longer than 10 ft. (3 M), any larger diameter vent pipe
shown in
Table 13
FOR THAT SIZE FURNACE may be used.
Combustion Air and Vent Piping Insulation
Guidelines
NOTE: Use closed cell, neoprene insulation or equivalent.
The vent pipe may pass through unconditioned areas. The amount of
exposed pipe allowed is shown in
1. Using winter design temperature (used in load calculations), find
appropriate temperature for your application and furnace model.
2. Determine the amount of total and exposed vent pipe.
3. Determine required insulation thickness for exposed pipe length(s).
4. When combustion air inlet piping is installed above a suspended
ceiling, the pipe MUST be insulated with moisture resistant
insulation such as Armaflex or other equivalent type of insulation.
5. Insulate combustion air inlet piping when run in warm, humid
spaces.
Table 15 – Maximum Allowable Exposed Vent Lengths in Unconditioned Space Insulation Table - Ft. / M
Unit Size
Uninsulated
Winter
Pipe Dia.
Design
1 ½
2
in.
Temp
20
20
20
°F
0
10
5
-20
5
-40
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Table 13
and note the
Table
15.
40,000* BTUH
3/8-in.
1/2-in.
Insulation
Insulation
2 ½
1 ½
2
2 ½
1 ½
20
20
50
45
20
5
20
25
20
20
20
15
10
20
15
10
5
15
6. Install the insulation per the insulation manufacturer's installation
instructions.
NOTE: Pipe length (ft. / M) specified for maximum pipe lengths located
in unconditioned spaces cannot exceed total allowable pipe length as
calculated from
Table
Configure the Furnace
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
To route the vent pipe and combustion air pipe through the furnace, the
manufacturer supplied kit must be used. Failure to properly seal the
blower compartment from the furnace vestibule could result in the
circulation of carbon monoxide throughout the structure. The vent pipe
and combustion air pipe must be a continuous pipe while passing
through the blower compartment. Seals supplied in this kit must be
installed per the instructions provided. Follow all procedures outlined
in these instructions.
Near Furnace Vent Connections
Offsets in the vertical portion of the vent pipe should be made with 45
deg. elbows instead of 90 deg. elbows. Short horizontal runs of vent pipe
are difficult to pitch correctly and may trap water in the vent pipe.
Trapped water in the vent pipe may result in nuisance pressure switch
tripping.
Install the Vent and Combustion Air Pipes
With the furnace installed in the required position, remove the desired
knockouts from the casing. It will be necessary to remove one knockout
for the vent pipe and the other knockout for the combustion air
connection. See
Fig.
Use a flat blade screwdriver and tap on the knockout on opposite sides,
where the knockout meets the casing. Fold the knockout down with duct
pliers and work the knockout back and forth until it is removed. Trim
any excess metal from the knockout with tin snips.
The vent elbow can be rotated to the required location on the casing if
necessary. See
Fig.
1. Loosen the clamp on the inlet of the vent elbow attached to the
inducer.
2. Rotate the vent elbow to the required position. There are rounded
notches on the vent elbow to align it with the inducer housing for
each orientation.
3. Tighten the clamp around the vent elbow. Torque the clamp to 15
lb-in. See
Fig. 53
Uninsulated
2
2 ½
1 ½
2
2 ½
60
50
20
30
30
30
25
15
15
10
20
15
10
5
15
10
5
46
13.
WARNING
!
15.
58. To rotate the vent elbow:
-
Fig.
56.
60,000 BTUH
3/8-in. Insulation
3
1 ½
2
2 ½
3
1 ½
25
20
75
65
60
20
10
20
40
30
25
20
20
25
20
15
20
20
15
15
10
20
1/2-in. Insulation
2
2 ½
3
85
75
65
45
40
30
30
25
20
20
15
10
Advertisement
Table of Contents
