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SCS Series Manual —
P/N 15712:L 7/18/16
181
HVAC Wiring Diagrams
Ratings and Wiring Diagrams
Figure 5.73 EP Damper Control - HVAC Switch Group Type 7
Figure 5.73 depicts an EP damper in an HVAC system with the capability of
CLOSED
control and verification of the
OPEN
and
CLOSED
state,
switch group type 7. In the above configuration, the CON
OFF⁄CL
CM is activated. The CON
OFF⁄CL
CM controls a normally open contactor for
the pressure switch power line. When the CON
OFF⁄CL
CM is activated, the normally open contactor is closed. When the contactor closes,
power is supplied to the pressure switch, which cuts the airflow to the damper, closing the damper. When the CON
OFF⁄CL
CM is deactivated,
the EMS is free to control the damper. The EMS is currently being overridden by the CON
OFF⁄CL
CM.
When power is supplied to the pressure switch, the damper closes. When the damper completely closes, the damper closed limit switch is
CLOSED
and the damper open limit switch is
OPEN
, indicating that the damper is in the
CLOSED
position. The VER
OFF⁄CL
MM monitors the
CLOSED
position of the damper closed limit switch and the VER
ON⁄OP
MM monitors the
CLOSED
position of the damper open limit switch. In
this case the VER
OFF⁄CL
MM is activated and the VER
ON⁄OP
MM is deactivated because the damper is
CLOSED
.
FMM-1
Airflow
PRESSURE
SWITCH
SMOKE
DAMPER
CLOSED
Power Source
Listed
24 VDC
Power Source
SLC Loop
FCM-1
CON
OFF/CL
CM
(activated)
D
e
p-
h7
A-
fs-
2
.w
m
f
Power
Return
VER
OFF⁄CL
MM
(activated)
N/O
COM
Limit Switch
for closed
position
ELR-47K
(use 3.9K listed ELR with FZM-1)
Pneumatic
Tubing
Energy
Management
System
1a listed
contactor
N/O
COM
Limit Switch
for open
position
VER
ON⁄OP
MM
(deactivated)
FMM-1
*If the SLC device
does not match the
one in this figure,
refer to the SLC
manual appendix,
which contains
wiring conversion
charts for type V
and type H
modules.