Robertshaw 8400 User Manual page 7

TERM EQUIPMENT TO CONNECT
Rh 24VAC hot connection
Rc 24VAC hot connection
W1 Heat connection
Y1 Compressor Connection
B Heat active reversing valve**
O Cool active reversing valve**
G Indoor fan connection
* This thermostat can be used as a heat only or cool only thermostat. Therefore it is not always
necessary to use both Y and W.
**The O and B terminals are accessory terminals that typically are used for heat pump applications.
G O B
ELECTRIC/GAS SWITCH
Selects fan control.
13. Make sure wire connections are secure.
14. Push excess wire back through opening.
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. Install two AA Energizer brand batteries or equivalent into
battery compartment as shown (Figure 5).
18. Replace thermostat cover by snapping into place.
TERMINAL LEGEND - 8400
° F
RH
NON_HP HP
RC
Y1 W1
ELEC GAS
REQ?
Yes
Yes
Yes*
Yes*
No
No
Yes
–
+
–
+
HP OPTION SWITCH
Heat pump switch.
Figure 5
7
TERMINAL FUNCTION
For input of 24VAC hot
side of heat transformer
For input of 24VAC hot
side of cool transformer
Energizes on a call for
heating
Energizes on a call for
cooling
Energizes when in the
HEAT mode
Energizes when in the
COOL mode
Energizes with Y1 & W1
terminals or with FAN
option switched to the
ON position
Correct battery
placement