3M Macurco CM-21A User Instructions - page 3
coil
Power
to remote 24vac alarm
transformer
24 vac
Main
fan power
Relay
24 vac coil
exhaust fan
CM-21A
Exhaust fan
air inlet
door, louver
damper
mount centrally
Typical layout in
small garage
(transformer
Controls
Typical Installation in small garage
red
red
yel.
yel
.
blue
brn.
org.
POWER
12/24V
ALARM
RELAY
SPDT fan
RELAY
CM-21A
red
red
yel.
yel
.
blue
brn.
org.
POWER
12/24V
ALARM
RELAY
SPDT fan
RELAY
CM-21A
red
red
yel.
yel
.
blue
brn.
org.
POWER
12/24V
ALARM
RELAY
SPDT fan
RELAY
CM-21A
red
red
yel.
yel
.
blue
brn.
org.
POWER
12/24V
ALARM
RELAY
SPDT fan
RELAY
CM-21A
coil
POWER
MAIN FAN
POWER
Relay
24 vac
coil
24 vac
remote alarm
exhaust fans
24 VAC
Transformer
Air Inlet
door, damper
louver
Air Inlet
door, damper
louver
CM-21A
CM-21A
CM-21A
exhaust fan
exhaust fan
controls
relay &
transformer
Typical layout in parking garage
INSTALLATION NOTES
1. One sensor per 5000 square feet (approximately).
2. Mount CM-21A four to five feet above the floor.
3. See applicable building code for fan size vs air
changes per periods of time.
4. Make sure there are air inlets to provide
adequate air flow throughout the building.
Typical multiple CM-21A installation
space sensors equally
& relay)
red
red
yel.
yel
.
blue
brn.
org.
POWER
12/24V
ALARM
RELAY
SPDT fan
RELAY
CM-21A
coil
MAIN FAN
POWER
exhaust fan
RELAY
12 or 24
vdc coil
Alarm Control Panel
12 or 24 vdc power
battery backed up
N.O. (fire)
initiating circuit
auxiliary functions
such as dialers.
Typical Connection to Alarm Control Panel
1. CM-21A can be used with 12vdc or
24vdc N.O. (fire) panels.
2. Alarm panel provides battery
backed up power to CM-21A.
3. CM-21A dry contact fan relay can
use panel power or fan power: check
ratings.
4. Match fan relay contacts to fan
size, and coil voltage to power source.
5. Alarm Control Panels are available with many
features & can control other devices such as smoke
detectors, fire detectors & burglar alarms.
(starter)
6. Several fan relays (starters) may be
used. Match the relays to the fan size.
5. CM-21A fan relays are dry contact &
can switch up to 240V: see ratings,
over.