Emerson 50A55 Troubleshooting, Integrated Furnace, Guide, Control Module, Chart, 5A5B, 5P YES

TROUBLESHOOTING		INTEGRATED FURNACE
GUIDE		CONTROL MODULE
	CHART 5

Flame

Sensor

Check

5A5B

Does main	YES	Does ignitor remain
burner remain		energized with
lit?		flame present?
NO		YES

5E

	5C
	Is blower
NO	at heat speed	YES
	within 1 minute
	of burner ignition?

NO

System is

functioning

properly.

5F

Is resistance

less than

50megohms (50,000,000

Ohms)?

YES

5G

Disconnect lead

from flame sensor. Connect ohmmeter from sensor to burner ground.

De-energize system.

Disconnect 12-pin connector. Connect ohmmeter from flame sensor pin FP to burner GROUND.

5I

	Disconnect flame
NO	sensor from wire.
	Measure continuity from
	wire end to FP pin
	on 12-pin connector.

5J

Is sensor	YES
lead good?
NO

5L

Disconnect AC power to system at main fuse or circuit breaker. Connect voltmeter from control terminal LINE NEUTRAL to BURNER GROUND. Energize module.

5K YES Is

control

ground wire connected to burner ground?

NO

5D

Is 120V

present at

control terminals YES HEAT & CIR NEUTRAL?

NO

5M

Is 120V

present at YES burner ground?

NO

5N

Connect a microammeter

in series with flame sensor and sensor lead. Energize system. Measure current when burner ignites.

5O

Repair wiring and/or replace indoor blower motor. Check operation.

Replace control module. Check operation.

Reverse 120V

LINE & NEUTRAL

wires. Energize system. Check operation.

Clean surface of flame sensor with fine steel wool. Reinstall. Check operation.

5P YES

TECHNICAL HELP

5H

Is resistance

less than

50 megohms?

YES

Replace sensor. Energize system. Check operation.

Repair or	Connect ground
	wire from burner to
replace wire.
	12-pin connector
Energize system.
	terminal GROUND.
Check operation.
	Check operation.

NO

Replace flame

sensor lead. Check

operation.

Is 1 microamp	NO
or more
present?
YES

Replace control.

Check operation.

Remove

sensor.

Does sensor

have carbon or

dust buildup?

NO

!WARNING

If diagnostic indicator (LED)

shows continuous flashing, turn off gas supply at source before disconnecting electrical power!

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