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SCS Series Manual —
P/N 15712:L 7/18/16
159
HVAC Wiring Diagrams
Ratings and Wiring Diagrams
Figure 5.50 Fan Control - HVAC Switch Group Type 13
Figure 5.50 depicts a fan in an HVAC system with the capability of
ON
and
OFF
control and verification of the
OFF
state, switch group type
13. 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 deactivated, the EMS is free to control the fan. In this case the EMS is
ON
, so power is being sup-
plied to the fan. When power is supplied to the fan, the fan is
ON
and the sail switch is
OPEN
, indicating airflow in the duct. The VER-
OFF⁄CL
MM monitors the
CLOSED
position of the sail switch, which would indicate when the fan is
OFF
.
In this case the VER
OFF⁄CL
MM is deactivated because the fan is
ON
due to the EMS. When the CON
ON⁄OP
CM is activated 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 turn-
ing 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
ELR-47K
(use 3.9K listed ELR with FZM-1)
Listed
Sail
Switch
N/O
COM
N/C
Power Return
Listed
24 VDC
Power Source
VER
OFF/CL
MM
(deactivated)
fa
n-
h1
3-
fs-
2
.w
m
f
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.
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.