CRISPAIRE/MARVAIR
Existing
Function
Terminals
Common
X
Power
R
Compressor
Y
1st Stg. Heat
–
Aux. Heat
W2
Fan
G
C/O Valve
B
Heat
C/O Valve
O
Cool
System Monitor/
A
System Defrost
EM. Heat
E
2nd Stage
–
Compressor
Terminal X or C must be connected to transformer common.
When W2 is not used, configure W2 cycle rate to NC.
Do not remove factory-installed jumper.
To eliminate automatic fan in emergency heat mode, connect switching relay
as shown on page 9.
70-6627 • 46
Electromechanical
X
X
X
R
R
R
Y
Y
Y
–
–
–
W2
W2
W2
G
G
G
B
B
B
O
O
O
L
L
L
E
E
E
–
–
–
Electronic Replacement or Upgrade
®
Chronotherm
III
C
C
R
R
or
Y1
Y
Y
W1
W1
W2
W2
G
G
B
B
O
O
O
L
L
E
E
–
–
Configure O/B (select models) in Installer Setup.
LED is energized when terminal is powered.
L terminal is powered continuously when thermostat is in Em. Ht. position.
Chronotherm
IV
C
C
C
R
R
R
Y1
Y
Y1
W1
W1
W1
W2
W2
W2
G
G
G
or
or
B
O/B
B
B
or
or
O/B
O
O
O/B
L
L
L
E
E
E
–
–
–
C
R
Y1/W1
–
Aux.
G
O/B
O/B
O/B
L
E
W2
M13151