CPRD Installation Manual

INSTALLATION INSTRUCTIONS
69-2770EFS-03
TrueZONE
®
Bypass (CPRD)
APPLICATION
The TrueZONE
®
Bypass constant pressure regulating damper
(CPRD) is a round static pressure relief damper. It is used in
forced-air bypass applications to relieve excess static
pressure when some of the zone dampers are closed. The
damper is installed in a duct that delivers air to the return or a
dump zone. The damper automatically opens and closes to
maintain a desired static pressure.
The CPRD uses a calibrated spring to regulate the bypass air
accurately when any number or combination of zones is
calling. Conventional, weighted arm, bypass dampers may
operate properly when one zone is calling; however, when
different combinations of zones are calling, they bypass too
much or too little. This can cause callbacks when
homeowners complain of air noise.
Selecting the Correct CPRD
1. Size the bypass damper by subtracting the cfm of the
smallest zone from the cfm of the system.
2. Consult Table 1 to determine the CPRD to use.
3. Example:
Bypass CFM = Total System CFM - Smallest Zone CFM
SPECIFICATIONS
Construction:
Galvanized steel, see Table 2
Temperature Range:
Ambient: 0F–165F (-17C–73C)
Storage: 30F–150F (-1C– 65C)
Table 1. Damper Sizing
DIMENSIONS
Table 2. CPRD Dimensions.
Bypass
Damper
Replacement
Regulator Maximum Airflow
CPRD8 CPR8 600 CFM
CPRD10 CPR10 1000 CFM
CPRD12 CPR12 1400 CFM
CPRD14 CPR14 1700 CFM
Model
ABCDE
Gaugein mm in mm in mm in mm in mm
CPRD8 8 203.2 9.65 245 1.50 38 11.54 292.84 4.65 118 26
CPRD10 10 254 11.42 290 1.50 38 13.50 343 4.65 118 26
CPRD12 12 305 13.18 235 1.50 38 15.47 392.84 4.65 118 24
CPRD14 14 355 14.96 380 1.50 38 17.36 441 4.65 118 22
M34207
D
E
B
C
A
Regulator
Damper