Installation Guide
4

69-2486—03

Wiring

See [notes] below

[1] Power supply. Provide disconnect means and overload protection as required.
 [3] Connectionto24VACcommonatthetransformerisrequired.
 [9] See"OptionalTHP9045WiringModule"on page 14 for more details.
Terminal Designations

Conventional Terminal Letters:

R Heating power. Connect to secon dary
side of heating system trans former.
Rc Cooling power. Connect to secon dary
side of cooling system trans former.
C Common wire from secondary side
of cooling transformer ( if 2 transform-
ers).
W 1st stage heat relay.
W2 2nd stage heat relay
Y 1st stage compressor contactor.
Y2 2nd stage compressor contactor.
G Fan rela y.
K OptionalTHP9045W iringModule
Terminal [9]

Heat Pump Terminal Letter s:

R Heating power. Connect to secon dary
side of heating system trans former.
Rc Cooling power. Connect to secon dary
side of cooling system trans former.
C Common wire from secondary side of
cooling system transfor mer.
Y 1st stage compressor contactor.
Y2 2nd stage compressor contactor.
Aux Auxiliary heat relay.
G Fan rela y.
E Emergency heat relay.
L Heat pump rese t (powered continu-
ously when System is set to Em He at;
system monitor when set to Heat ,
Cool or Off).
O/B Changeover valve for heat pumps .
K OptionalTHP9045W iringModule
Terminal [9]

1H/1C System (1 transformer)

Rc Power [1]
R [R+Rc joined by jum per]
W Heat relay
Y Compressor contactor
G Fan relay
C 24VACcommon[3]
K OptionalTHP9045W iringModule
Terminal [9]

Heat Only System

Rc Power [1]
R [R+Rc joined by jum per]
W Heat relay
C 24VACcommon[3]

Heat Only System (S eries 20)

Rc [R+Rc joined by jum per]
R Series 20 valve terminal “R” [1]
W Series 20 valve terminal “B”
Y Series20valvete rminal“W”
C 24VACcommon[3]

2H/2C System (1 transf ormer)

Y2 Cool relay 2
W2 Heat relay 2
Rc Power [1]
R [R+Rc joined by jum per]
W Heat relay 1
Y Cool relay 1
G Fan relay
C 24VACcommon[3]
K OptionalTHP9045Wi ringModule
Terminal [9]
Wiring guide—conventional systems