Dual Fuel Operation - York LX series Owner's Manual

Installer Setup
Lockout Heat Pump On Outdoor Temp
This feature stops the heat pump from running below a specified outdoor temperature,
where the heat pump has become inefficient or could damage equipment.
Lockout Heat Pump With Outdoor Temp (Setup Step 46) - When set to ON, the Heat
Pump Lockout feature is enabled. When set to OFF, the heat pump will stage normally.
Heat Pump Lockout Temp (Setup Step 47) - (10 - 45 ) This step allows the user to set
the temperature at which the heat pump will be locked out. Adjustable from 10 to 45
degrees Fahrenheit in five degree increments.
Auxiliary Heat Lockout (Setup Steps 48 -49)
This feature allows the auxiliary heat for a heat pump
(W2 and W3) to be locked out above a specific outdoor
temperature. These steps will only appear if the
thermostat jumper J1 is set for Heat Pump and J3
is set for Electric Heat.
Lockout Aux Heat With Outdoor Temp (Setup Step 48) - When set to ON, the Aux
Heat Lockout feature is enabled. When set to OFF, Auxiliary Heat will stage normally.
Aux Heat Lockout Temp (Setup Step 49) - (20 - 75 ) This step allows the user to set
the temperature at which Auxiliary Heat will be locked out. Adjustable from 20 to 75
degrees Fahrenheit.
NOTE: This temperature setting cannot be lower than 5 degrees above
the Heat Pump Lockout temperature.
Dual Fuel (Setup Steps 50 - 54)
(This feature not available on all models)
This feature is for heat pump applications only.
Steps 50 - 54 will only appear if the thermostat jumper
J1 is set for Heat Pump and J3 is set for Gas Heat.
Dual Fuel On, Off, or External (Setup Step 50) - On - Tells the thermostat an outdoor
temperature or a demand for third stage heat will be used to stop running the heat pump
and only run a fossil fuel source of heat. NOTE: Once the change to fossil fuel is made,
the heat demand must finish with fossil fuel. Additional heat demands within 10 minutes
will also use fossil fuel, regardless of outdoor temperature. External - This setting
allows the use of an external fossil fuel kit. This may be a third party fossil fuel kit or
part of the heat pump control.
CAUTION - this setting will allow the heat pump and furnace to run at
the same time unless an external fossil fuel kit is properly connected.
(If External is chosen setup steps 51 - 54 will not have any effect.)
(Setup Steps 46 -47)
Jumpers are located on the
back of the thermostat
GAS/ELEC RV=O
J1 J2
HEATPUMP RV=B
Jumpers are located on the
back of the thermostat
GAS/ELEC RV=O
J1 J2
HEATPUMP RV=B
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GAS
J3
ELEC
GAS
J3
ELEC