18-CD35D1-1 15
INSTALLER’S GUIDE
DOWNFLOW/ HORIZONTAL VENTING TABLE
MAXIMUM VENT LENGTH:
MODEL
DIRECT VENT (2 PIPE SYSTEM) - MAXIMUM TOTAL
EQUIVALENT FEET FOR VENT AND INLET AIR PIPES
(SEE NOTES)
NON-DIRECT VENT (1 PIPE SYSTEM) - MAXIMUM
TOTAL EQUIVALENT FEET FOR VENT PIPES ONLY
(SEE NOTES)
2" PIPE &
FITTINGS
2-1/2" PIPE
& FITTINGS
3" PIPE &
FITTINGS
4" PIPE &
FITTINGS
2" PIPE &
FITTINGS
2-1/2" PIPE
& FITTINGS
3" PIPE &
FITTINGS
4" PIPE &
FITTINGS
M951P040BD24AA
60
80
100
130
50
80
80
130
M951P065BD42AA
45
80
100
130
40
80
80
130
M951P085CD48AA
NA
80
100
130
NA
80
80
130
M951P110DD60AA
NA
15
60
130
NA
NA
50
130
NOTES: * - First letter may be "A" or "T", NA = NOT ALLOWABLE
1. The INLET AIR of one pipe systems require the installation of a 90° elbow (to prevent dust and debris from falling straight into the furnace)
and a 2 foot horizontal or vertical straight pipe section connected before or after the elbow.
2. DO NOT MIX PIPE DIAMETERS IN THE SAME LENGTH OF PIPE OUTSIDE THE FURNACE CABINET (Except adapters at the top of the
furnace). If different inlet and vent pipe sizes are used, the vent pipe must adhere to the maximum length limit shown in the table above (See
Note 7 below for exception). The inlet pipe can be of a larger diameter, but never smaller than the vent pipe.
3. MAXIMUM PIPE LENGTHS MUST NOT BE EXCEEDED! THE LENGTH SHOWN IS NOT A COMBINED TOTAL, IT IS THE MAXIMUM
LENGTH OF EACH (Vent or Inlet air pipes in two pipe systems).
4. One standard radius 90° elbow is equivalent to 12' of 4" pipe; one SHORT radius 90° elbow is equivalent to 10' of 3" pipe and one LONG
radius elbow is equivalent to 6' of 3" pipe. One SHORT/LONG radius 90° elbow is equivalent to 7½' of 2½" pipe, and 5' of 2" pipe. Two 45°
elbows equal one 90°elbow.
5. The termination tee or bend must be included in the total number of elbows. If the BAYAIR30AVENTA termination kit is used, the equivalent
length of pipe is 5 feet. There is zero equivalent length for the BAYVENT200B.
6. Pipe adapters are field supplied.
7. 4" pipe may be reduced to 3" for termination with BAYAIR30AVENTA or BAYVENT200B without additional length restriction.
8. For Canadian applications Only: IPEX 196006 may be used for horizontal and vertical terminations. IPEX 081216, IPEX 081218, and IPEX
081219 may only be used for horizontal vent terminations. Equivalent lengths are IPEX 196009 = 5 feet, IPEX 081216 = 11 feet, IPEX 081218
= 16 feet, and IPEX 081219 = 21 feet.
TABLE 12
Vent only
to outside
Air Inlet
B
A
A (0-2') or greater
B (0-2') or greater
A+B = 2' minimum
UPFLOW FURNACE
g
Vent only
to outside
Air Inlet
A
A = 2' minimum
DOWNFLOW
FURNACE
SINGLE PIPE VENTING
NOTE:
To ensure proper operation at the vent lengths
indicated, the combustion air inlet and vent
terminals should be in the same pressure
zone. Terminating the vent and inlet in different
pressure zones will change the maximum vent
lengths and may cause nuisance tripping of the
pressure switch(es). The amount of change can
not be predicted. The selection of the inlet and
outlet terminal locations are the responsibility
of the designer/installer. If the installer chooses
separate pressure zones for the terminals, the
combustion air inlet termination must be in the
higher (more positive) pressure zone.
IMPORTANT:
Products installed in Canada must use vent
systems that are certified to the Standard for Type
BH Gas Venting Systems (ULC S636) for Class II-A
venting systems (up to 65°C). Components of the
vent system must not be interchanged with other
vent systems or unlisted pipe or fittings. Plastic
components, specified primers, and glues must
be from a single system manufacturer and not
intermixed with other system manufacturer's
vent system parts. In addition, the first three feet
of the vent pipe must be visible for inspection.
