International comfort products B Series Installation Instructions Manual page 43

INSTALLATION INSTRUCTIONS
furnace input size. Compare the Total Equivalent Vent
Length (TEVL) to the MEVL:
a. 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.
b. 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
Figure 49 Optional Combustion Air Inlet Moisture Trap
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 Table 17.
1. Using winter design
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.
440 01 4102 01
TO CODE−APPROVED DRAIN OR CONDENSATE PUMP
Representative drawing only, some models may vary in appearance
temperature (used in load
Specifications subject to change without notice.
length of all the fittings and terminations (TEVL), recalculate
Total Equivalent Vent Length using the next smaller diameter. If
the Maximum 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 with pipe lengths of 10 ft. (3.0 M)
or less, use the smallest allowable pipe diameter. Using 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. (3.0 M), any larger diameter
shown in Table 14 or Table 16 for that size model may be
used.
5. Insulate combustion air inlet piping when run in warm,
humid spaces.
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 (See Table 17) cannot exceed
total allowable pipe length as calculated from Table 14 through
Table 16.
Gas Furnace: N9MSB
L12F028
43