Fig. 9—Typical hookup for MABS XX Control Panel with T874A Thermostat/Q674B,E Subbases in single-
stage heating-cooling zone system.
MABS XX
CONTROL PANEL
HEAT
MCM
TO SINGLE-
STAGE
Y
W
HEATING/
COOLING
EQUIPMENT
1
2
1
L2
L1
(HOT)
2
T874A
THERMOSTAT/
Q674B OR E
SUBBASE
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
2
WIRE ONLY THE TERMINAL CONNECTIONS SHOWN. SOME TERMINALS NOT AVAILABLE ON ALL THERMOSTATS. IF THERMOSTAT HAS
R/RC/RH TERMINALS, JUMPER TOGETHER AND WIRE AS SINGLE R TERMINAL. DO NOT CONNECT THERMOSTAT O AND B TERMINALS
TO CONTROL PANEL.
ZONE 1
FAN
COOL
G Gh
O
B
RC RH
ZONE 1
G
Y
R
W M6 M4 M1 VO VC
G
Y1
Y2
R
W1
W2
O
4
5
6
B
DAMPER
ACTUATOR
1
2
3
ZONE 2
HEAT
FAN
COOL
ZONE 1
FAN
ZONE
SYS
DAMPER
OPEN
CLOSE
ZONE 2
Y
R
W
G
M6 M4 M1 VO VC
G
Y1
Y2
R
W1
2
W2
O
Z
4
B
DAMPER
ACTUATOR
T874A
X
1
THERMOSTAT/
Q674B OR E
SUBBASE
6
ZONE 3
HEAT
FAN
CAC
FC
ZONE 2
ZONE 3
FAN
FAN
ZONE
SYS
ZONE
SYS
DAMPER
DAMPER
OPEN
CLOSE
OPEN
CLOSE
W M6 M4 M1 VO VC
G
Y
R
G
Y1
Y2
R
W1
2
W2
O
5
6
Z
B
T874A
2
3
X
THERMOSTAT
Q674B OR E
SUBBASE
COOL
1
2
3
4
5
6
7
8
9
ZONE 3
4
5
6
Z
DAMPER
ACTUATOR
1
2
3
X
M1636