York LX series Owner's Manual page 18

Installation Instructions
Explanation of Thermostat Jumpers
Jumpers are located on the back of the thermostat
GAS/ELEC RV=O GAS
J1 J2 J3
HEATPUMP RV=B ELEC
GAS/ELEC GAS/ELEC
This jumper configures the thermostat to control a conventional
gas/electric system or a heat pump. If your system is anything
J1
OR
other than a heat pump, leave this jumper set for GAS/ELEC.*
HEATPUMP HEATPUMP
*For some commercial heat pumps, this jumper will need to
be set for GAS/ELEC. Consult the commercial heat pump literature.
RV=O RV=O When J1 is configured to control a heat pump, this jumper (J2)
must be set to control the appropriate reversing valve. If RV=O
J2
OR
is chosen, the W1/O/B terminal will energize in cooling. If RV=B
is chosen, the W1/O/B terminal will energize in heating.
RV=B RV=B
When J1 is set for GAS/ELEC:
This jumper (J3) controls how the thermostat will control the
Fan (G) terminal in heating mode. When GAS is chosen, the
thermostat will not energize the Fan (G) terminal in heating.
GAS GAS
When ELEC is chosen the thermostat will energize the fan in
J3 heating.
OR
When J1 is set for HEATPUMP:
ELEC ELEC
This jumper (J3) defines the Aux Heat type. When GAS is
chosen, the auxiliary heat will not be allowed to run during
heat pump operation. When using a Dual Fuel system, set this
jumper for GAS. When ELEC is chosen, up to two stages of
auxiliary strip heat will be allowed to run.
GAS/ELEC
J1 J2
HEATPUMP
C
AUX
OUTDOOR
SENSOR
REMOTE
SENSOR
DRY
CONTACT
FAULT
Page 10
RV=O GAS
J3
RV=B ELEC
R
G
W1/O/B
W2
Y1
Y2
W3
HUM
DEHUM