
SERVICING
42
L2
INDUCER
LOW HIGH
L1
OD F
LOW HIGH
T1
Q3
K4
K3
K5
K6
T2
K7
FS
U1
U2
U6
U7
U4
U5
U3
P2
K2
K1
ECON
STAGE
DELAY
C9
SPEED UP
SW1
FAULT
RECALL
BLOWER
OFF DELAY
F1
R C W1W2 G
Y2
90
120
150
180
10MIN
5 MIN
NONE
PARK
1
2
3
4
5
Y1
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
WARNING
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.
Flame
Sensor
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 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.