16
18-CD20D3-18
Installer’s Guide
Seal
VENT PIPE
with RTV sealant
Seal
INLET AIR PIPE
with RTV sealant
Front of Furnace
VENT AND INLET AIR CONNECTIONS
f
Connection of the pipe and collar of the combustion air inlet
should just be a friction fit. It is recommended that the inlet
air joint be sealed with RTV type sealant to allow the joint to
be separated for possible future service. The inlet and vent
pipes must be properly supported throughout the entire
length.
Connection of the vent pipe to the vent collar should also be
accomplished using RTV type sealant. This type sealant
provides a connection which remains flexible and can be
separated in the future if service needs require the removal of
the vent pipe for service or clearance.
▲
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow the installation instructions for the venting
system being placed into operation could result in carbon
monoxide poisoning or death.
HIGH ALTITUDE DERATE
Input ratings (BTUH) of these furnaces are based on sea
level operation and should not be changed at elevations up to
2,000 ft.
If the installation is 2,000 ft. or above, the furnace input rate
(BTUH) shall be reduced 4% for each 1,000 ft. above sea
level.
The furnace input rate shall be checked by clocking the gas
flow rate (CFH) and multiplying by the heating value
obtained from the local utility supplier for the gas being
delivered at the installed altitude. Input rate changes can be
made by adjusting the manifold pressure (min 3.0 - max
3.7 in. W.C. - Natural Gas) or changing orifices (orifice change
may not always be required).
VENT LENGTH TABLE
ALTITUDE
MAXIMUM TOTAL EQUIVALENT LENGTH IN FEET
FOR VENT AND INLET AIR (SEE NOTES)
0-7,000 Feet
2 INCH PIPE
2.5 INCH PIPE
3 INCH PIPE
UY/DY060R9V3
200
200
200
UY/DY080R9V3
50
120
200
UY/DY100R9V4
Not Allowed
60
200
UY/DY120R9V5
Not Allowed
Not Allowed
200
7,000-9,500 Feet
2 INCH PIPE
2.5 INCH PIPE
3 INCH PIPE
UY/DY060R9V3
100
100
100
UY/DY080R9V3
25
60
100
UY/DY100R9V4
Not Allowed
30
100
UY/DY120R9V5
Not Allowed
Not Allowed
100
9,500-12,000 Feet
2 INCH PIPE
2.5 INCH PIPE
3 INCH PIPE
UY/DY060R9V3
50
50
50
UY/DY080R9V3
Not Allowed
30
50
UY/DY100R9V4
Not Allowed
Not Allowed
50
UY/DY120R9V5
Not Allowed
Not Allowed
50
NOTES: * - First letter may be "A" or "T"
1. Minimum vent length for all models: 3' horizontal or 3' vertical.
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 6 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).
4. 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
90° elbow is equivalent to 7½' of 2½" pipe or 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 BAYVENT100A termination kit is used,
the equivalent length of pipe is 5 feet. BAYVENT200A equivalent length is 0 feet.
6. Pipe adapters are field supplied. Downflow models, UY100, and UY120 include 2" X 3" pipe adapter.
