Checking Flame Sensor - Daikin DBG Series Service Instructions Manual

SERVICING
Flame Detected with Gas Valve Closed
If flame is detected with the gas valve deenergized, the
combustion 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
The automatic ignition control has a built-in feature that pre-
vents damage to the compressor in short cycling situations.
In the event of intermittent power losses or intermittent ther-
mostat operation, the ignition control will delay output to the
compressor contactor for three minutes from the time power
is restored. (Compressor is off a total of three minutes). The
diagnostic LED will flash six (6) times to indicate the compres-
sor contactor output is being delayed.
NOTE: Some electronic thermostats also have a built-
in compressor 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 additional five minutes to allow
the thermostat to complete its short cycle delay time.
NOTE: The flash rate is 0.25 seconds on, 0.25 seconds
off, with a 2-second pause between codes.
S-314 CHECKING FLAME SENSOR
A flame sensing device is used in conjunction with the ignition
control module to prove combustion. If a microamp signal
is not present the control will de-energize the gas valve and
"retry" for ignition or lockout.
DSI Direct Spark Ignition Systems
HIGH VOLTAGE!
Disconnect ALL power before servicing
or installing this unit. Multiple power
sources may be present. Failure to do so
may cause property damage, personal injury
or death.
1. Disconnect the flame sensor wire from terminal FS of the
ignition control module.
50
(5 FLASH CODE)
(6 FLASH CODE)
Flame Sensor
2. Connect a microamp meter in series with this wire and
terminal FS.
3. Be sure the negative side of the meter is to the wire and
the positive of the meter is to terminal FS.
4. Turn on Power.
WARNING
Line Voltage now present.
5. With Power ON, Place the unit into a heating cycle.
6. As soon as flame is established a microamp reading
should be evident once proof of flame (microamp reading)
is established, the hot surface ignitor will be de-energized.
7. The microamp reading should be 4 - 6 microamps.
8. If the microamp current is less than 0.5 microamp the control
will lockout and flash a code of 1 flash after attempting to
reestablish flame sense.
9. If the microamp reading is less than the minimum spec-
ified, check for high resistance wiring connections, the
distance (3/16") between the sensor and burner, flame
sensor connections, dirty flame sensor or poor grounding.
10. If no reading, check for continuity on all components and
if good - replace ignition control module.
NOTE: Contaminated fuel or combustion air can create
a nearly invisible coating on the flame sensor. This
coating works as an insulator causing a loss in the
flame sense signal. If this situation occurs the flame
sensor must be cleaned with steel wool. Do not use
sand paper, the silicone in sand paper will further
contaminate the sensor.
Flame
Sensor