Honeywell Heat/1Cool - T841A1563 Premier 2 Stage Thermostat User Manual page 111

Existing
Function
Terminals
Common
X
Power
R
Compressor
Y
1st Stage
–
Heat
Aux. Heat
W2
Fan
G
C/O Valve
–
Heat
C/O Valve
O
Cool
System Monitor/
L
System Defrost
Em. Heat
E
Multiple Aux.
Heat Loads
W3
LED Indication
A
2nd Stage
–
Compressor
2nd Stage
–
Cool
Configure O/B (select models) in Installer Setup.
When W2 is not used, configure W2 cycle rate to NC.
Terminal is for multiple auxiliary heat loads such as contactors, sequencers,
or relays.
Optional LED indication activated with completed circuit on X1 and
X2 terminals.
If multiple auxiliary heat loads are used, connect to W2 (Aux W8900B)
terminal.
T874C1570/Q674B1000
T874R1236/Q674L1348
Electromechanical
X X X
R R R
Y Y Y1
– W1 W1
W2 W2 W2
G G G
B B B
O O O
L
E E E
W3 W3 W3
– X2 X1 X2
– – –
– – –
TYPICAL THERMOSTATS AND SUBBASES — HONEYWELL MODEL NUMBER
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
X1 X2 –
– –
– –
Terminal must be connected to the transformer common.
Do not remove factory-installed jumper.
Optional Check LED on T8611G1004. See Fig. 26.
Field-installed X2 to X (C) jumper.
LED is energized when terminal is powered.
L terminal is powered continuously when thermostat is in Em. Ht. position.
T874L1455/Q674L1322
T874R1392/Q674L1447
WILLIAMSON
COOLING CHANGEOVER
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
L L L
E E E
– – X1 X2
– – –
– – –
70-6627 • 109
C
R
Y1/W1
–
Aux.
G
O/B O/B
O/B O/B
L
E
–
W2
Y2
M13213