Unit Fails To Fire In The Heating Mode, Combustion Air Inducer Does Not Energize - Lennox G61MPV Service Manual

PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER DOES NOT
Flash Code
LED X + Y
2.1
Unit operates with a cooling or
continuous fan demand.
Combustion air inducer will not start
with a Heating demand. g
Diagnostic lights flash the limit failure Di ti li ht fl h th li it f il
mode.
LED 3 + 1
2.2
Unit operates with a cooling and
continuous fan demand.
Combustion air inducer will not start
with a Heating demand.
Diagnostic lights flash the pressure Diagnostic lights flash the pressure
switch failure code.
LED 2 +4
2.3
Unit operates with a cooling or
continuous fan demand.
Combustion air inducer will not start
with a Heating demand.
Diagnostic lights flash the open
rollout failure mode.
LED 5 + 1
PROBLEM 3: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR INDUCER DOES
Condition
3.3
Unit operates with a cooling and
continuous fan demand.
Combustion air inducer will not start
with a Heating demand.
Diagnostic lights flash the pressure Diagnostic lights flash the pressure
switch failure code 2.5 minutes after
heating demand.
LED 2 + 3
ENERGIZE
Possible Cause
2.1.1
Primary Limit or secondary limit
(if equipped ) open.
2.1.2
Miswiring of furnace or improper con-
nections at limit switch(es).
2.2.1
Miswiring of furnace or improper con-
nections to combustion air inducer.
2.2.2
Prove switch stuck closed.
2.3.1
Rollout Switch Open.
NOT ENERGIZE
Possible Cause
3.3.1
Miswiring of furnace or improper con-
nections to combustion air inducer.
3.3.2
Combustion air inducer failure.
Page 98
Corrective Action / Comments
ACTION 1 − Check continuity across switch(es).
Switches reset automatically upon cool down.
ACTION 2 − Check for restrictions on blower inlet
air (including filter) and outlet air. Determine
cause for limit activation before placing unit back
in operation.
ACTION 1 − Check for correct wiring and loose
connections. Correct wiring and/or replace any
loose connections.
ACTION 1 − Check for correct wiring and loose
connections. Correct wiring and/or replace any
loose connections.
ACTION 1 − Check that the prove switch is open
without the combustion air inducer operating. Re-
place if defective.
ACTION 1 − Check continuity across rollout
switches. Rollout switches must be manually re-
set.
ACTION 2 − Look for restrictions in vent pipe or
combustion air inlet or heat exchanger. Deter-
mine cause before placing unit in operation.
Corrective Action/Comments
ACTION 1 − Check for correct wiring and loose
connections. Correct wiring and/or replace any
loose connections.
ACTION 1 − If there is 120V to combustion air in-
ducer and it does not operate, replace combus-
tion air inducer.