SERVICING
55
01 UltraCheck-EZ
TM
diagnostic tool . If the motor runs
with the diagnostic tool, the motor is good. To check
the end bell, see the previous variable speed testing
section of this manual before replacing the end bell.
b. The two-stage variable speed furnaces should have
120 Volts at the motor at all times, even without a
call for cooling or heating. These motors receive their
operational signals through the 4-pin wiring harness,
connected between the motor and integrated control
board.
NOTE:
For complete troubleshooting
MEMORY CHIPS (Comfortbridge™ Only)
On a ComfortBridge™ furnace using the shared data memory
chip is a “last resort.” The CoolCloudHVAC™ App should be
used to populate shared data to the control via the “Shared
Data” menu under Furnace tab.
CHECKING FLAME SENSOR
A flame sensing device is used in conjunction with the ignition
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
VOLTAG
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ER
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ATH
.
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 sensor
terminal.
L
IN
E
VOLTAG
E
NOW
P
RE
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E
NT
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 reading)
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 minimum
specified, check for high resistance wiring connections,
sensor to burner gap, dirty flame sensor, or poor
grounding.
7. If absolutely 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.
