Lennox International Inc 61H42, LB-83114C i---No, Start Here, across, engaging?

DEFROST CONTROL TROUBLESHOOTING FLOWCHART

START HERE

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Check control transformer primary and secondary voltages. Repair or replace as necessary.

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Turn off power to unit.

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Check defrost sensor. Is sensor temperature or pressure acti-

............i ....	1	.o___1
Is defrost control set for	Is compressor		contactor
30, 60 or 90 minute de =		energized?
frost intervals?
	i---No	................I	Yes

Check thermostat and thermostat widng. Repair or replace as necessary

vated? For help in determining, re- fer to operation of control in unit installation instructions and unit wiring diagram.

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Repeat troubleshooting procedure.

Does un_ go into defrost within appropriate time?

Check circuit from "HLD" terminal back to thermo- stat, Repair or replace as necessary.

t

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Pressure			Temperatu		re
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	Is sensor			making good
		contact		with	coil?
	Yes _				No
					I
					Repair or
				replace sensor
					bracket.
Check all electrical		connections
at the defrost control. Defrost
sensor	and defrost		relay.
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Connect	a jumper		across
the defrost		relay.
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Connect a jumper across the two

Yes		No _		Repeat			troubleshooting
			]			procedure.
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Unit is operating	properly.	Check		voltage across "OUT"
Turn off power	to unit,	terminal		and	"COM"		terminal.
Remove all test jumpers.			Is voltage		24 ±		6VAC?
Reassemble	unit.

Yes

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Connect a jumper between "OUT" terminal

and "COM" terminal. CAUTION-Be careful not to short "OUT" terminal to "24v" terminal,

Permanent controt damage could result.

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Does unit go immediately into defrost?

Yes t

No

"TST" pins on the delrost Control,

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Turn indoor thermostat to

heat mode and adjust to high-

est temperature setting.

1

Turn on power to unit.

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Turn off power to unit. Remove all test jumpers.

Replace defrost control with new control board,

Repeat troubleshooting procedure.

Check voltage across de- frost relay coil. Is voltage 24 ± 6VAC?

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["-_ Yes _ No

Check voltage across "HLD"
terminal and "COM" termi-
nal, Is voltage 24 + 6VAC?
1
	I	Yes
ls solenoid	engaging?
Yes _t	No
i	1
Replace reversing	Replace solenoid.
valve. Repeat	Repeat troubleshoot-
troubleshooting	ing procedure,
procedure.

Is defrost relay energized?

					Yes		I	No
Check voltage			across re=
versing valve coil. Is volt-							Check	voltage	across "24Y"
	age 24 ÷		6VAC?
		I	I				terminal and "COM" terminal. Is
							voltage 24 ± 6VAC?
			No					I	Yes
						NO	,,,, ,,,,,,	_
			I			I			I
Turn off power to unit.
					Turn off power to unit.
Check	and repair		circuit
				Check circuit			from defrost
from	reversing		valve					Turn	off power	to unit.
					switch	back	to control
through		defrost relay to						Replace defrost		relay,
					transformer. Repair of re-
control		transformer.						Repeat troubleshooting
					place	as necessary,
Repeat	troubleshooting								procedure.
					Repeat	troubleshooting
	procedure.
					procedure,

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