Lennox G26 Series - Continuous Low Speed Fan Sequence; Heating Sequence of Operation

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Page 42
D- SureLight Control Trouble Shooting Guide
UPON INITIAL POWER UP, REMOVE ALL THERMOSTAT DEMANDS TO THE UNIT
PROBLEM: 1 UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE
Condition Possible Cause Corrective Action / Comments
1.1
- Both diagnostic lights fail to light up.
1.1.1
Main voltage 120V not supplied to
unit.
ACTION 1 - Check 120V main voltage.
Determine cause of main power failure.
LED#1-Off
LED#2-Off
1.1.2
Miswiring of furnace or improper
connections.
ACTION 1 - Check for correct wiring of 120V to
power make up box and transformer.
ACTION 2 - Check 24V wiring to control board.
1.1.3
Circuit breaker tripped or fails to
close.
ACTION 1 - Replace circuit breaker if it is reset
but does not have continuity.
ACTION 2 - If circuit breaker still trips, check for
short.
1.1.4
Door interlock switch failure.
ACTION 1 - Check that door switch is activated
when door is closed.
ACTION 2 - Check wire connections to switch, reĆ
place loose connectors.
ACTION 3 - Check continuity of switch in closed
position. Replace if malfunctioning
1.1.5
Transformer Failure.
ACTION 1 - Check that transformer output is
24V. Replace if malfunctioning
1.1.6
Failed control board.
ACTION 1 - If all the above items have been
checked, replace board.
1.2
- Diagnostic lights flash the roll-out
code.
1.2.1
Roll-out switch open.
ACTION 1 - Manually reset the roll-out switch
by pushing the top button.
ACTION 2 - Determine the cause of the roll-out
switch activation before leaving furnace.
code
.
LED#1 O
1.2.2
Roll-out switch failure.
ACTION 1 - Check continuity across roll-out
switch. Replace roll-out switch if switch is reset
but does not have continuity.
LED#1-On,
LED#2-Slow Flash
1.2.3
Mis iring or improper connections at
ACTION 1 - Check wiring connections to switch
LED#2 Slow
Flash
Miswiring or improper connections at
roll-out switch.
ACTION
1
-
Ch
ec
k
w
i
r
i
ng connect
i
ons to sw
i
tc
h
.
1.2.4
Nine pin connector failure
ACTION 1 - Check 9-pin connector for proper
connection to control board.
ACTION 2 - Check continuity of the multi plug
pin.
1.3
- On initial power-up the comb. air
b
l
o
w
e
r
does
n
ot
e
n
e
r
g
iz
e
.
blower
does
not
energize
.
- Diagnostic lights flash the reverse
polarity code.
1.3.1
120V main power polarity reversed.
ACTION 1 - Check the 120V has line and neutral
correctly input into control.
ACTION 2 - Reverse the line and neutral at the
120V field connection.
LED#1-Fast Flash,
LED#2-Slow Flash.
120V
field
connection.
1.4
- On initial power up the combustion
air blower does not energize.
- Diagnostic lights flash normal power
on o
p
eration.
1.4.1
Open combustion air blower motor
circuit.
ACTION 1 - Check for 120V to combustion air
blower. If no power, check wire and connecĆ
tions.
on
operation
.
LED#1-Slow Flash
LED#2-Slow Flash
1.4.2
Failed combustion air blower motor.
ACTION 1 - If power is present at blower, replace
blower.
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