Robertshaw 8425 User Manual page 7

110-1090.qxd 7/22/04
TERMINAL LEGEND - 8425
TERM EQUIPMENT TO CONNECT
R 24 VAC hot connection
C 24 VAC common connection
L System fault indicator
connection
W1 Second stage connection
for non heat-pump applications
Y2 Second stage cooling
connection
Y1 First stage compressor
connection
W2/E Second stage heat or
Emergency heat connection
B Heat active reversing
valve connection
O Cool active reversing
valve connection
G Indoor fan connection
* Do not connect W1 in heat pump applications. Connect auxiliary heat to W2/E.
** Most heat pump systems will have a cool active or a heat active reversing valve. Use the
appropriate terminal.
C
Y2
R
W2/E
NON_HP HP
L
G O B Y1 W1
ELEC GAS
ELECTRIC/GAS SWITCH
Selects fan control.
15. Set the Electric/Gas switch to either GAS for a gas/oil heating
system or ELEC for an electric heating system (Figure 5).
16. Set the HP option switch to either the HP for heat pump or
NON_HP for furnace applications (Figure 5).
17. Replace thermostat cover by snapping into place.
8:39 AM Page 7
REQ? TERMINAL FUNCTION
Yes For input of 24VAC hot
side of transformer
Yes For input of 24VAC
common side of
transformer
No For connection of system
fault indicator (if present)
No* Energizes on a call
for heat
No Energizes on a call for
second stage cooling
Yes Energizes on a call for
first stage of heating
and cooling
Yes* Energizes on a call for
second stage or
emergency heat
Yes** Energizes when in the
HEAT or EM modes
Yes** Energizes when in the
COOL mode
Yes Energizes with E & Y1, Y2
and W2 terminals or with
FAN option switched to
the ON position
° F
HP OPTION SWITCH
Heat pump switch.
Figure 5
7