11
ES SPLIT INSTALLATION MANUAL
Dual Fuel Systems
ES units can be connected to fossil fuel furnaces that include an A-coil or slab coil. Dual fuel installations utilize the
ES heat pump for heating until the point that auxiliary heat is called for on the thermostat. At that point, the furnace will be
enabled and the heat pump will be disabled. The ES heat pump provides air conditioning through the furnace’s refrigerant
coils.
Refer to the furnace manufacturer’s installation manual for the furnace installation, wiring and coil insertion. A fi eld-in-
stalled SPDT auxiliary heat relay is required. See Figure 7 for typical Dual Fuel application. Figure 8 shows the wiring for
Single Speed ES units. Figure 9 shows wiring for Dual Capacity ES units.
Figure 7: Typical Split System Application - Heat Pump Coil Add-On Fossil Fuel Furnace
Fault Signal
Fossil Fuel
Furnace
C
R
L0
Reversing Va lve
Commo n
C
R
G
W
Commo n
24 VA C
Fa n
Auxiliary Heat
1st Stage Compressor
Split
Thermostat
Y1
L
O
Y2
C
W
G
R
Y2
O
2nd Stage Compressor
24 VA C
Auxiliary Heat Relay
Y1
Fault Signal
Fossil Fuel
Furnace
C
R
L0
Reversing Valve
Common
C
R
G
W
Common
24 VAC
Fan
Auxiliary Heat
1st Stage Compressor
ES Split
Thermostat
Y1
L
O
Y2
C
W
G
R
Y2
O
2nd Stage Compressor
24 VA
Emergency Shutdown
Note: Field installed SPST dual fuel relay
(Required for dual fuel installation)
C
Auxiliary Heat Relay
Y1
P1
P2
ES
Figure 8: Single Speed Dual Fuel Wiring
Figure 9: Dual Capacity Dual Fuel Wiring
Electrical (cont.)
Lineset
To Air Handler
Insulated Suction
Line
Return
Duct
Low
Voltage Wire
Disconnect
Remote Air Handler
(Maximum Recommended Distance is
50' Between Units)
Supply
Duct
Up-Flow
Fossil Fuel
Furnace
Condensate
Drain
(must be trapped)
"A" or
Slab Coil
Wire To
Thermostat
