156 SCS Series Manual — P/N 15712:L 7/18/16
Ratings and Wiring Diagrams HVAC Wiring Diagrams
Figure 5.47 Fan Control - HVAC Switch Group Type 9
Figure 5.47 depicts a fan in an HVAC system with the capability of ON control and verification of the OFF state, switch group type 9. In the
above configuration, the CON
ON⁄OP
CM is deactivated. 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 is deactivated, the EMS is free to control the fan. In this case the EMS is
OFF, so no power is being supplied to the fan. When no power is supplied to the fan, the fan is OFF and the sail switch is CLOSED, indicating
no 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 activated because the fan is OFF due to the EMS. When the CON
ON⁄OP
CM is activated, 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.
FRM-1
COM
N/O.
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
(activated)
fan-h9-fs-2.wmf
SLC Loop
FAN OFF
Energy Management System
FMM-1
CON
ON/OP
CM
(deactivated)
*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.
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