GMEC96 Service Manual
TROUBLESHOOTING
43
Symptoms
Green
LED Code
Amber
LED Code
Re d
LED Code
Fault Description Check Cautions
• Furnace does not
operate, four Red
flashes on cont rol board
• None • None
• Four
repeati ng
flashes
• Open limit circuit, main
li m it , aux limit, or roll out
sw itch
• Temperat ure rise, duct stat i c,
gas pressure, burner alignment ,
orifice plate position, wiring to
all limits
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, five Red
flashes on cont rol board
• None • None
• Five
repeati ng
flashes
• Limit & rollout circuit open
for 15 minutes. Open cont rol
board fuse or rollout sw it ch
• Cont rol board fuse,
Temperature rise, duct static,
gas pressure, burner alignment ,
orifice plate position, wiring to
all limits
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, six Red flashes
on cont rol board
• No n e • No ne
• Six
repeati ng
flashes
• Pressure swi t ch cycling
lockout , pressure sw itch has
opened 5 times in the same
heatin
g
c
y
cle
• Excessive venting restriction,
leaking pressure sw i tch tubing
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, seven Red
flashes on cont rol board
• None • None
• Seven
repeati ng
flashes
• Lockout - excessive ret ries
from flame not being proven
during trial for ignit ion
• Gas pressure, gas valve, front
cover pressure sw i tch, f lame
rod
• Confirm electrical and
gas safe condit ions
before proceeding with
repairs
• Furnace does not
operate, eight Red
flashes on cont rol board
• None • None
• Eigh t
repeati ng
flashes
• Lockout - excessi ve recycl es
from flame proving being lost
af ter being proven
• Gas pressure, gas valve, front
cover pressure sw i tch, f lame
rod
• Confirm electrical and
gas safe condit ions
before proceeding with
repairs
• Furnace does not
operate, nine Red
flashes on cont rol board
• None • None
• Nin e
repeati ng
flashes
• Improper grounding or
reverse polarit y
• 115 vo lt hot & n eut ral sup ply
t o f urnace reversed, hot w ire
(door sw it ch & L1 on control
board) must read 115 volt s to
ground & neut ral. Neut ral wire
should measure 0 volts t o
ground
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, ten Red flashes
on cont rol board
• No n e • No ne
• Ten
repeati ng
flashes
• Gas valve current detected
wit h no call for heat
• Verify gas valve is not
receiving voltage from an
electrical short. If valve wiring
is correct replace cont rol board
• Confirm electrical and
gas safe condit ions
before proceeding with
repairs
• Furnace does not
operate, eleven Red
flashes on cont rol board,
inducer running
• Non e • No ne
• Eleven
repeati ng
flashes
• Open limit sw itch circuit for
more than 5 minut es
• Re-set main pow er and check
indoor blow er operation
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, twelve Red
flashes on cont rol board
• None • None
• Tw el ve
repeati ng
flashes
• Cont rol board igniter relay
not energizing igniter
• Repl ace cont rol b o ard
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, cont rol board
Red LED on solid
• None • None • Solid ON • Control board internal fault • Replace cont rol board
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, cont rol board
Red LED rapid flash
• None • None • Rapid Flash • Tw inning error • Correct tw inning w iring
• Confirm electrically safe
condit ion before
proceeding with repairs
• Furnace does not
operate, cont rol board
Red LED w ith t hree
double flashes
• None • None
• Three
double
flashes
• Second stage pressure
sw itch stuck open
• Verify pressure switch
function & tubing, verify
inducer operating and pulling
enough vacuum to engage
sw itch
• Confirm electrically safe
condit ion before
proceeding with repairs