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158
SCS Series Manual —
P/N 15712:L 7/18/16
Ratings and Wiring Diagrams
HVAC Wiring Diagrams
Figure 5.49 Fan Control - HVAC Switch Group Type 12
Figure 5.49 depicts a fan in an HVAC system with the capability of
ON
and
OFF
control, switch group type 12. In the above configuration, the
CON
ON⁄OP
CM is deactivated and the CON
OFF⁄CL
CM is deactivated. These two control modules are always in the opposite state when the
smoke control system is in operation and are always deactivated during normal operation. The CON
ON⁄OP
CM is wired in parallel with the
EMS; when wired in parallel with the EMS the CM must be a relay module. When the CON
ON⁄OP
CM and the CON
OFF⁄CL
CM are deacti-
vated, the EMS is free to control the fan. In this case the EMS is
ON
, so power is being supplied to the fan. When the CON
ON⁄OP
CM is acti-
vated for smoke control, the CON
ON⁄OP
CM overrides whatever state the EMS is in and closes the normally open contactor, thus supplying
power to the fan and turning it
ON
. When the CON
OFF⁄CL
CM is activated for smoke control, the CON
OFF⁄CL
CM opens the normally closed
contactor and turns the fan
OFF
, overriding whatever state the EMS is in.
Power Source
1a listed
contact
Service
Disconnect
Switch
Power Return
Listed
24 VDC
Power Source
fa
n-h
1
2
-f
s
-2.
wmf
SLC Loop
FAN ON
Energy Management System
CON
ON/OP
CM
(deactivated)
FCM-1
CON
OFF/CL
CM
(deactivated)
Listed
24 VDC
Power Source
1b listed
contact
FRM-1
COM
N/O.
*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.