Duel-Fuel Operations - Lennox EIM Installation And Setup Manual

Duel-Fuel Operations

To use the EIM in dual-fuel mode, the following equipment combinations
and configuration is required.
Defrost Air Tempering Kit (67M41) will be required. The included DT1
discharge temperature probe is inserted in the furnace air outlet between
the furnace and the indoor coil to keep the furnace from overheating
the coil which would cause heat pump high pressure tripping during the
defrost cycling. The DT1 is only needed with non-communicating furnaces
and is not required for air handlers.
Wiring example for the DT1 Discharge Temperature Probe is in "Figure
13. Dual-Fuel - Conventional Furnace with Conventional Heat Pump
(1 or 2-Stage)" on page 12.
Lennox Communicating Equipment Interface
Thermostat
Wiring Legend
4-wire communicating
24VAC conventional
Figure 7. EIM, Conventional Furnace and Lennox Communicating Heat Pump
Model (EIM)
Lennox
Communicating
Heat Pump
(Outdoor Unit)
Outdoor Sensor
(Included with
Heat Pump)
Defrost Tempering
(Available only if
furnace is variable
capacity
or multi-stage)
Optional
Lennox
Communicating
Thermostat
Non-Communicating
Furnace
Figure 8. EIM, Conventional Furnace and Conventional Heat Pump
9
Lennox
Equipment Interface
Communicating
Model (EIM)
Furnance
Wiring Legend 4-wire communicating
24VAC conventional
24VAC
Conventional Heat
Pump
(Outdoor Unit)
X2658 Outdoor
Sensor Required