Checking Flame Sensor - Daikin APGM3 Service And Troubleshooting

SERVICING
L2
LOW
T1
K4
Q3
FS
T2
C9
U6
5
4
U7
3
U4
2
1 U3
U5
180
SPEED UP
F1
150 NONE
120 5 MIN
SW1 10MIN
90
BLOWER STAGE
FAULT ECON
RECALL OFF DELAY DELAY
PCBAG127 DSI Control Board

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. 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.
L1
INDUCER OD F
PARK
HIGH LOW HIGH
K6
K3 K5
K7
U2 P2
U1
K2
K1
R C W1W2 G Y1 Y2
WARNING
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.
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 nominal microamp reading is 4 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
specified, 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
WARNING
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