
154
SCS Series Manual —
P/N 15712:L 7/18/16
Ratings and Wiring Diagrams
HVAC Wiring Diagrams
Figure 5.45 Fan Control - HVAC Switch Group Type 6
Figure 5.45 depicts a fan in an HVAC system with the capability of
OFF
control and verification of the
ON
state, switch group type 6. In the
above configuration, the CON
OFF⁄CL
CM is deactivated. The CON
OFF⁄CL
CM controls a normally closed contactor which switches power to
the fan (the contactor is used when the power being switched is greater than 24 volts). When the CON
OFF⁄CL
CM is deactivated, the contactor
is closed, thus allowing the EMS to freely 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
ON⁄OP
MM monitors the
OPEN
position of the sail switch, which would indicate when the fan is
ON
. In this case the VER
ON⁄OP
MM is deactivated because the fan is
OFF
due to the EMS. When the CON
OFF⁄CL
CM is activated, the normally closed contactor opens, thus cutting any power to the fan that was
being supplied by the EMS.
Switch group type 7 is for a fan that would require the capability of
OFF
control and verification of both the
ON
and
OFF
states. Since it is pos-
sible to determine this information from either switch group type 5 or switch group type 6, switch group type 7 would only be necessary for
redundancy in verifying the state of the fan. For example, if switch group type 5 were used instead of switch group type 7, the
OFF
state of the
fan would be verified when the monitor module is activated and the
ON
state of the fan would be verified when the monitor is deactivated.
Utilizing switch group types 5 or 6 also saves the use of an additional monitor module. Switch group type 7 would use two monitor modules
to provide the same verification as types 5 or 6.
Power Source
Service
Disconnect
Switch
ELR-47K
(use 3.9K listed ELR with FZM-1)
Listed
Sail
Switch
N/O
COM
N/C
Power Return
VER
ON/OP
MM
(deactivated)
fa
n-
h6
-f
s
-2
.w
m
f
SLC Loop
FAN OFF
Energy Management System
Listed
24 VDC
Power Source
FMM-1
Listed contact for
Energy
Management
System
1b listed
contact
Listed
24 VDC
Power Source
FCM-1
CON
OFF/CL
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.