Carrier 912SD Installation, Start-Up, Operating And Service And Maintenance Instructions page 39

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912SD: Installation, Start-up, Operating and Service and Maintenance Instructions
Include a deduction for a Tee when used for Alberta and Saskatchewan
terminations.
NOTE: Polypropylene venting systems MAY require additional
deductions from the MEVL, or additions to the TEVL, for vent
terminations and flexible pipe sections. See the polypropylene venting
system manufacturer's instructions for details on equivalent lengths of
vent terminations and flexible vent pipes, and for calculating total vent
lengths.
To calculate the Total Equivalent Vent Length (TEVL) of the venting
system:
Tee
Dry Well
Cap
(water tight
and removable)
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
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
A
TO CODE- -APPROVED DRAIN OR CONDENSATE PUMP
Recommend "T" fitting with 4- -inch minimum height standpipe (A) of same diameter or larger extending upward.
Dry Well
(water tight
and removable)
Representative drawing only, some models may vary in appearance.
Fig. 51 – Recommended Combustion Air Inlet Moisture Trap
Table 13
and note the
1. Measure the individual distance from the furnace to the termination
for each pipe.
2. Count the number of elbows for each pipe.
3. For each pipe, multiply the number of elbows by the equivalent
length for the type of elbow used. Record the equivalent length of
all the elbows for each pipe.
4. If a Tee is used on the termination (Alberta and Saskatchewan,
when required) record the equivalent length of the Tee used.
5. Calculate Total Equivalent Vent Length by adding the equivalent
lengths of the fittings to the lengths of the individual vent and
combustion air pipes.
A
Tee
Cap
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
39
A
Tee
Dry Well
Cap
(water tight
and removable)
.
FOR THAT SIZE FURNACE may be used.
m
A170122A

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