Daikin DFG Series Installation Instructions Manual page 25

The diagnostic fault code is 1 flash for a lockout due to failed igni-
tion attempts or flame dropouts. The integrated control will auto-
matically reset after one hour, or it can be reset by removing the
thermostat signal or disconnecting the electrical power supply for
over five seconds. If the diagnostic LED indicates an external lock-
out, perform the following checks:
• Check the supply and manifold pressures
• Check the gas orifices for debris
• Check gas valve for proper operation
• Check secondary limit
A dirty filter, excessive duct static, insufficient air flow, a faulty lim-
it, or a failed circulator blower can cause this limit to open. Check
filters, total external duct static, circulator blower motor, blower
motor speed tap (see wiring diagram), and limit. An interruption
in electrical power during a heating cycle may also cause the aux-
iliary limit to open. The automatic reset secondary limit is located
on top of the circulator blower assembly.
• Check rollout limit
If the burner flames are not properly drawn into the heat ex-
changer, the flame rollout protection device will open. Possible
causes are restricted or blocked flue passages, blocked or cracked
heat exchanger, a failed induced draft blower, or insufficient com-
bustion air. The rollout protection device is a manual reset limit lo-
cated on the burner bracket. The cause of the flame rollout must
be determined and corrected before resetting the limit.
• Check flame sensor
A drop in flame signal can be caused by nearly invisible coating
on the sensor. Remove the sensor and carefully clean with steel
wool.
• Check wiring
Check wiring for opens/shorts and miswiring.
IMPORTANT: If you have to frequently reset your gas/electric
package unit, it means that a problem exists that should be cor-
rected. Contact a qualified servicer for further information.
Pressure Switch Stuck Open
A pressure switch stuck open can be caused by a faulty pressure
switch, faulty wiring, a disconnected or damaged hose, a blocked
or restricted flue, or a faulty induced draft blower.
If the control senses an open pressure switch during the pre-
purge cycle, the induced draft blower only will be energized. If
the pressure switch opens after ignition has begun the gas valve
is deenergized, the circulator blower heat off cycle begins, and
the induced draft blower remains on. The diagnostic fault code is
two flashes.
Pressure Switch Stuck Closed (3 FLASH CODE)
A stuck closed pressure switch can be caused by a faulty pres-
sure switch or faulty wiring. If the control encounters a pressure
switch stuck closed, the induced draft blower remains off. The
diagnostic LED code for this fault is three (3) flashes.
(2 FLASH CODE)
Open Thermal Protection Device
If the primary limit switch opens, the gas valve is immediately
deenergized, the induced draft and air circulating blowers are en-
ergized. The induced draft and air circulator blowers remain ener-
gized until the limit switch recloses. The diagnostic fault code for
an open limit is four (4) flashes.
A primary limit will open due to excessive supply air tempera-
tures. This can be caused by a dirty filter, excessive duct static,
insufficient air flow, or a faulty limit. Check filters, total external
duct static, blower motor, blower motor speed tap (see wiring
diagram), and limit. This limit will automatically reset once the
temperature falls below a preset level.
Flame Detected with Gas Valve Closed
If flame is detected with the gas valve deenergized, the combus-
tion and air circulator blowers are energized. The diagnostic fault
code is five (5) flashes for this condition. The control can be reset
by removing the power supply to the unit or it will automatically
reset after one hour. Miswiring is the probable cause for this fault.
Abnormal Operation - Cooling Codes
Short Cycle Compressor Delay (6 FLASH CODE)
The automatic ignition control has a built-in feature that prevents
damage to the compressor in short cycling situations. In the event
of intermittent power losses or intermittent thermostat opera-
tion, the ignition control will delay output to the compressor con-
tactor for three minutes from the time power is restored. (Com-
pressor is off a total of three minutes). The diagnostic LED will
flash six (6) times to indicate the compressor contactor output is
being delayed.
NOTE: Some electronic thermostats also have a built-in compres-
sor short cycle timer that may be longer than the three minute
delay given above. If you are using an electronic thermostat and
the compressor has not started after three minutes, wait an addi-
tional five minutes to allow the thermostat to complete its short
cycle delay time.
to prevent unreliable operation or equipment damage, the
gas manifold pressure must be as specified on the unit
rating plate. Only minor adjustments should be made by
adjusting the gas valve pressure regulator.
25
(4 FLASH CODE)
(5 FLASH CODE)
CAUTION