Service - Lennox ELITE EL297DFXV045P36B Installation Instructions Manual

6 - When the thermostat heating demand is satisfied,
the combustion air inducer begins a 5-second low
speed post-purge. The field-selected indoor blower
off delay begins. The indoor blower operates at the
low-fire heating speed.
1
ON
OFF
1 stg heat demand
low speed CAI
ignitor
low fire gas valve
indoor blower low heat
2 stg heat demand
high speed CAI
high fire gas valve
indoor blower high heat
* Conventional thermostat 30 seconds, communicating thermostat set for 30 adjustable 15 to 45 seconds.
ON
OFF
heat demand
low speed CAI
ignitor
low fire gas valve
indoor blower low heat
7 or 12 minutes after heating demand begins, furnace switches to high fire (depends on setting)
high speed CAI
high fire gas valve
indoor blower high heat
* Conventional thermostat 30 seconds, communicating thermostat set for 30 adjustable 15 to 45 seconds.

Service

WARNING
ELECTRICAL SHOCK, FIRE,
OR EXPLOSION HAZARD.
Failure to follow safety warnings exactly could result in
dangerous operation, serious injury, death or property
damage. Improper servicing could result in dangerous
operation, serious injury, death, or property damage.
Before servicing, disconnect all electrical power to
furnace. When servicing controls, label all wires prior to
disconnecting. Take care to reconnect wires correctly.
Verify proper operation after servicing.
Annual Furnace Maintenance
At the beginning of each heating season, and to comply
with the Lennox Limited Warranty, your system should be
checked as follows:
HEATING OPERATION WITH TWO-STAGE THERMOSTAT
15
Pre-Purge
Ignitor Warm-up
30 seconds
HEATING OPERATION WITH SINGLE STAGE THERMOSTAT
15
1
Ignitor Warm-up
Pre-Purge
7 - When the combustion air post-purge period is
complete, the inducer and the HUM contacts are
de-energized. The indoor blower is de-energized at
the end of the off delay as well as the 120V ACC
terminals.
35 39 80
30* second
blower
Trial For
"on" delay
Ignition
RECOGNITION PERIOD
FIGURE 63
35 39
30* second
Trial For
blower
Ignition
"on" delay
FIGURE 64
The blower access panel must be securely in place when
the blower and burners are operating. Gas fumes, which
could contain carbon monoxide, can be drawn into living
space resulting in personal injury or death.
1 - Check wiring for loose connections, voltage at
indoor unit and amperage of indoor motor.
2- Check the condition of the belt and shaft bearings if
applicable.
3- Inspect all gas pipe and connections for leaks.
4- Check the cleanliness of filters and change if
necessary (monthly).
5- Check the condition and cleanliness of burners and
heat exchanger and clean if necessary.
Page 61
5 SEC
80
WARNING
blower
"off"
Post
delay
Purge
5 SEC
blower
"off"
Post
delay
Purge