Troubleshooting - Daikin DFG Series Installation Instructions Manual

Flame Sensor (Qualified Servicer Only)
A drop in the flame current can be caused by a nearly invisible
coating on the flame sensor. This coating, created by the fuel or
combustion air supply, can be removed by carefully cleaning the
flame sensor with steel wool.
NOTE: After cleaning, the microamp signal should be stable and in
the range of 4 - 6 microamps DC.
Flue Passages (Qualified Servicer Only)
At the start of each heating season, inspect and, if necessary,
clean the unit flue passage.
Inspection & Cleaning
All flue product carrying areas of the furnace, its vent system, and
main burners should be examined by a qualified service agency
before the start of each heating season. This examination is nec-
essary for continued safe operation. Particular attention should
be given to deterioration from corrosion or other sources. This
examination is accomplished in the following manner.
1. Disconnect power to the unit lock and tag out and re-
move furnace section access panel.
2. Remove burner assembly:
a. Disconnect the three wires from the gas valve after
noting which wires are connected to each terminal.
b. Disconnect wires from the flame rod and ignition
electrode.
c. Disconnect the gas piping at the union.
d. The entire burner assembly can now be removed
from the unit.
NOTE: Use all screws that were removed; they are necessary for
safe and proper operation of the unit.
3. Inspect and periodically clean the vent outlet (bird screen)
on the access panel.
NOTE: Periodic observation of the flame and a log of C0
ments are recommended. This will aid in determining whether the
furnace is operating efficiently or if the furnace requires cleaning.
Flames should be stable, soft and blue (dust may cause orange
tips but must not be yellow). The flames must extend directly out-
ward from the burner without curling, floating or lifting off.
BURNER FLAME
To avoid personal injury or death due to electrical shock,
do not remove any internal compartment covers or attempt
any adjustment. Contact a qualified servicer at once if an
abnormal flame should develop.
At least once a year, prior to or during the heating season, make a
visual check of the burner flames.
NOTE: This will involve removing and reinstalling the heat ex-
changer door on the unit, which is held by two screws. If you are
uncertain about your ability to do this, contact a qualified servicer.
If a strong wind is blowing, it may alter the airflow pattern within
the unit enough that an inspection of the burner flames is not
possible.
Functional Parts
Refer to the unit Parts Catalog for a list of functional parts. Parts
are available from your distributor.
Ignition Control Error Codes
The following presents probable causes of questionable unit op-
eration. Refer to Diagnostic Indicator Chart for an interpretation
of the signal and to this section for an explanation.
Remove the control box access panel and note the number of di-
agnostic LED flashes. Refer to Diagnostic Indicator Chart for an
interpretation of the signal and to this section for an explanation.
Internal Control Failure
If the integrated ignition control in this unit encounters an inter-
nal fault, it will go into a "hard" lockout and turn off the diagnostic
LED. If diagnostic LED indicates an internal fault, check power sup-
measure-
ply to unit for proper voltage, check all fuses, circuit breakers and
2
wiring. Disconnect electric power for five seconds. If LED remains
off after restoring power, replace control.
Abnormal Operation - Heating Codes
External Lockout
An external lockout occurs if the integrated ignition control de-
termines that a measurable combustion cannot be established
within three (3) consecutive ignition attempts. If flame is not
established within the seven (7) second trial for ignition, the gas
valve is deenergized, 15 second inter-purge cycle is completed,
and ignition is reattempted. The control will repeat this routine
three times if a measurable combustion is not established. The
control will then shut off the induced draft blower and go into a
lockout state.
If flame is established but lost, the control will energize the circu-
lator blower at the heat speed and then begin a new ignition se-
quence. If flame is established then lost on subsequent attempts,
the control will recycle for four (4) consecutive ignition attempts
(five attempts total) before locking out.
24
WARNING

TROUBLESHOOTING

(1 FLASH CODE)