GMEC96 Service Manual

TROUBLESHOOTING
42
Symptoms
Green
LED Code
Amber
LED Code
Re d
LED Code
Fault Description Check Cautions
• Furnace fails to operate
• Control board LED is of f
• None • No ne • No ne
• Defective disconnect switch
• defective door swit ch • No
115 vo l t po w er • No 24 vol t
power
• Determine cause and restore
proper high and low volt pow er
supply
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace is waiting for a
call
• Solid ON • None • None
• Furnace is not receiving a
call
• None Required
• Confirm electrically safe
condit ion before
proceeding with w ork
• Furnace fan only is
running
• Rapid Flash • None • None
• Furnace i s receiving a call for
fan (24 volts on G terminal
• None Required
• Confirm electrically safe
condit ion before
proceeding with w ork
• Normal operation w it h
low stage call for cooling
(Ylo & G)
• One
repeati ng
flash
• No ne • No ne
• Normal operation with low
stage call for cooling (Ylo & G)
• None Required
• Confirm electrically safe
condit ion before
proceeding with w ork
• Normal operation w it h
hi gh or singl e st age cal l
f or coo li ng (Y & G)
• Tw o
repeati ng
flashes
• No ne • No ne
• Normal operation w it h high
or single stage call for cooling
(Y & G)
• None Required
• Confirm electrically safe
condit ion before
proceeding with w ork
• Normal operation w it h
low stage call for heat
(W1)
• None
• On e
repeat i ng
flash
• None
• Normal operation with low
stage call f or heat (W1)
• None Required
• Confirm electrically safe
condit ion before
proceeding with w ork
• Normal operation w it h
high or single stage call
for heat
• None
• Tw o
repeat i ng
flashes
• None
• Normal operation w it h high
or single stage call for heat
• None Required
• Confirm electrically safe
condit ion before
proceeding with w ork
• Furnace does not
operate, three Amber
flashes on cont rol board
• None
• Three
repeat i ng
flashes
• None • W2 call present wit hout W1
• Faulty t herm ostat or
thermostat wiring or
improperly connected
thermost at wires
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, four Amber
flashes on cont rol board
• None
• Four
repeat i ng
flashes
• None
• Yl o or Y call present w ithout
G
• Faulty t herm ostat or
thermostat wiring or
improperly connected
thermost at wires
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, rapid Amber
flashes on cont rol board
• None • Rapid • None • Low flame sense current
• Dirt y / co at ed fl am e ro d, poo r
flame, improper gas pressure,
poor flame sense w ire or
connections
• Clean flame rod with
steel wool. Confirm
electrically safe condition
bef ore proceeding w ith
repairs
• Furnace does not
operate, one Red flash
on control board
• None • No ne
• One
repeat ing
flash
• Flame sensed when no
flame should be present
• Gas valve st uck open,
improper wiring to gas valve,
short ed flame rod or wire
• Conf i rm electrical and
gas safe condi t ions
bef ore proceeding w ith
repairs
• Furnace does not
operate, two Red
flashes on control board,
possible inducer
operation
• None • No ne
• Tw o
repeat ing
flashes
• Pressure sw it ch stuck closed
• Faulty pressure swit ch,
pressure sw itch w ires shorted,
cont rol board inducer relay
stuck closed
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, three Red
flashes on cont rol board
• None • No ne
• Three
repeat ing
flashes
• Low f ire pressure sw i t ch
stuck open
• Faulty pressure swit ch,
pressure switch or tubing or
w iring / connection, cont rol
board inducer relay failed, vent
pipe restricti on / excessive
elbow s or length
• Confirm electrically safe
condit ion before
proceeding with repairs