Service Manual

SYSTEM OPERATION
78
2 Y2
HUM
OG Y1C W1 R
DE
W2
1
Memory Card
Connector
Dual 7-Segment
LED’
s
4. Power the system back up and allow a few minutes for
the network to establish communication between all de-
vices.
5. Furnace control board will display "ON”.
6. Check operation.
7. Memory chip can be left on the control board (recom-
mended) or removed once equipment is powered down
again.
S-314 CHECKING FLAME SENSOR
A flame sensing device is used in conjunction with the igni-
tion control module to prove combustion. If proof of flame is
not present the control will de-energize the gas valve and
"retry" for ignition or lockout.
WARNING
HIGH VOLTAGE
D
ISCONNECT 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 the sensor.
2. Connect a micro-amp meter in series with this wire and
the sensor terminal.
3. Be sure the positive side of the meter is to the flame
sensor wire and the negative side of the meter is to sen-
sor terminal.
L
INE VOLTAGE NOW PRESENT
WARNING
4. Place the unit into a heating cycle.
5. As soon as flame is established a micro-amp reading
should be evident once proof of flame (micro-amp read-
ing) is established, the hot surface ignitor will be de-
energized.
6. The Integrated Ignition controls will have 1 to 4 micro-
amps. If the micro-amp reading is less than the mini-
mum specified, check for high resistance wiring con-
nections, sensor to burner gap, dirty flame sensor, or
poor grounding.
7. If absolutely no reading, check for continuity on all com-
ponents 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.