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INSTALLATION INSTRUCTIONS
69-1518-2
Static Pressure Regulating Damper
(SPRD)
APPLICATION
The Static Pressure Regulating Damper (SPRD) is a
round or rectangular single-blade barometric relief
damper. It is a mechanical damper with no electrical
connections. The blade has a counter-balance weighted
arm that can be adjusted to open when necessary. It is
recommended for use on zone damper systems up to.5
in. static pressure and up to 2000 cfm. Systems above
2000 cfm may require use of the SPC static pressure
control and MARD damper.
The SPRD is used on zoned systems when the
automatic closing of zone dampers can create an
excessive increase in the air pressure and velocity
through the duct system. This increase can reduce the
volume of air through the air handler and cause it to trip
on high limit or to create ice on the coil.
The SPRD automatically opens as the air pressure in the
duct system increases, and ducts the air into the return or
dump zone. Both the position of the counterweight and
the swing of the arm can be adjusted to allow the SPRD
to open when necessary. See Fig. 1 and 2 for SPRD
dimensions.
The counterweight arm assembly and counterweight only
are available as replacement parts. See Fig. 3.
INSTALLATION
When Installing This Product…
1. Read these instructions carefully. Failure to follow
them could cause a hazardous condition.
2. Check that all components are included. The
SPRD package includes: SPRD damper, counter-
weight arm assembly and installation instructions.
3. Check the ratings given in the instructions and on
the product to make sure the product is suitable for
your application.
4. Installer must be a trained, experienced service
technician.
5. After installation is complete, check out the product
operation as provided in these instructions.
Selecting Damper Size
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 correct rectangu-
lar or round SPRD to use.
3. Alternately, calculate the bypass damper size using
a duct-sizing calculator. Use.25 in. for a bypass
zone and.1 in. for a dump zone.
Table 1. SPRD Damper Sizing.
Rectangular Recommended cfm Round Recommended cfm
12 x 8 1000 7 300
12 x 10 1200 8 400
12 x 12 1400 9 600
20 x 8 1600 10 750
20 x 10 2000 12 1200
20 x 12 3000 14 1800
— — 16 2400
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