Lennox 84W88 Installation Instructions Manual

Lennox 84W88 Installation Instructions Manual

Replacement defrost control kit used with various heat pumps

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Installation INSTRUCTIONS FOR REPLACEMENT DEFROST CONTROL KIT (84W88)
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property.
Installation and service must be performed by a licensed
professional installer (or equivalent) or a service agency.
WARNING
Electric Shock Hazard. Can cause injury
or death. Unit must be grounded in
accordance with national and local
codes.
Line voltage is present at all components
when unit is not in operation on units with
single‐pole contactors. Disconnect all
remote electric power supplies before
opening access panel. Unit may have
multiple power supplies.

Shipping and Packing List

Package 1 of 1 contains:
4 - 1/4" quick connect terminals
2 - Black wire
1 - Wire (1 foot in length)
1 - Defrost control replacement - information sticker
(401843S)

Application

Replacement defrost control kit (84W88) includes defrost
control 100269. This defrost control may be used in
various heat pump units to replace any defrost control
listed in table 1. The 100269 includes features which may
not be found in all of the existing controls. If the unit was
originally equipped with any defrost control other than a
100269 series, operation should be reviewed at the time of
replacement. Features of 100269 defrost control include:
Five-minute compressor anti-short cycle delay;
Pressure switch lockout circuit;
Loss of charge / low pressure switch circuit;
Field-selectable compressor delay
Field connection terminals for service light.
HEAT PUMP UNITS
KITS AND ACCESSORIES
504,587M
3/2014
Supersedes1/2013
USED WITH VARIOUS HEAT PUMPS
Page 1
REPLACEMENT DEFROST
Table 1. Applicable Defrost Controls
Original Defrost Control
100269-01, -02 and -04
29M0101
29M0201
56M3701
68J2901
68J8401

Defrost System

The defrost system includes a defrost thermostat and a
defrost control.

DEFROST THERMOSTAT

The defrost thermostat is located on the liquid line between
the check/expansion valve and the distributor. When the
defrost thermostat senses 42°F (5.5°C) or cooler, its
contacts close and send a signal to the defrost control to
start the defrost timing. It also terminates defrost when the
liquid line warms up to 70°F (21°C).
DEFROST CONTROL (CMC1)
The defrost control includes the combined functions of a
time/temperature defrost control, defrost relay, time delay,
Diagnostic Leds, and a terminal strip for field wiring
connections.
The control provides automatic switching from normal
heating operation to defrost mode and back. During
compressor cycle (defrost thermostat is closed, calling for
defrost), the control accumulates compressor run times at
30, 60, or 90 minute field adjustable intervals. If the defrost
thermostat is closed when the selected compressor run
time interval ends, the defrost relay is energized and
defrost begins.
Defrost Control Timing Pins (P1)
Each timing pin selection provides a different
accumulated compressor run time period for one defrost
cycle. This time period must occur before a defrost cycle
is initiated. The defrost interval can be adjusted to 30
(T1), 60 (T2), or 90 (T3) minutes (see figure 1). The
maximum defrost period is 14 minutes and cannot be
adjusted. Factory default is 90 minutes
If the timing selector jumper is missing, the defrost
control defaults to a 90-minute defrost interval.
Litho U.S.A.
CONTROL
Replacement Defrost Control
100269-05

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Table of Contents
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Summary of Contents for Lennox 84W88

  • Page 1 KITS AND ACCESSORIES Litho U.S.A. REPLACEMENT DEFROST 504,587M 3/2014 CONTROL Supersedes1/2013 INSTALLATION INSTRUCTIONS FOR REPLACEMENT DEFROST CONTROL KIT (84W88) USED WITH VARIOUS HEAT PUMPS Table 1. Applicable Defrost Controls WARNING Original Defrost Control Replacement Defrost Control Improper installation, adjustment, alteration, service or...
  • Page 2 FIELD SELECT TIMING PINS TEST PINS DIAGNOSTIC LEDS COMPRESSOR DELAY PINS REVERSING VALVE SERVICE LIGHT CONNECTIONS LOW PRESSURE SWITCH 24V TERMINAL STRIP CONNECTIONS DEFROST THERMOSTAT HIGH PRESSURE SWITCH Figure 1. Defrost Control (100269-05) Bypass-Anti-Short Cycle Delay Test Mode The TEST mode is activated by removing the jumper on The Y1 input must be active ON, the high pressure switch the defrost termination pins (30, 60 or 90) and placing the must be closed or a jumper must be installed on the high...
  • Page 3 Test Mode Sequence switches heat/cool modes. If the TEST pins are jumpered and the 5-minute delay is being bypassed, Using the defrost termination pin, short the TEST pins for the LO PS terminal signal is not ignored during the a period of two seconds: 90-second start-up period.
  • Page 4 Figure 2. Typical Unit Wiring Diagrams - Defrost Control with C, L and Y1 Terminals) Page 4...
  • Page 5 Figure 3. Typical Unit Wiring Diagrams - Defrost Controls with W1, C, L and T, T terminals) Figure 4. Earlier Model Defrost Control Terminal Designations for Service Light and Ambient Thermistor Connections Page 5...
  • Page 6 Figure 5. Wiring Ambient Compensator (RT3) and Service Light and Service Light Thermostat (S54) to New Defrost Control Page 6...
  • Page 7 Figure 6. Wiring Ambient Compensator (RT3) and Service Light and Service Light Thermostat (S54) to New Defrost Control Page 7...
  • Page 8 Figure 7. Connector Descriptions 4. Position replacement defrost control properly over Installation mounting holes in unit and snap stand-offs into place. 5. Reconnect labeled wires to the proper terminals on the CAUTION replacement defrost control. Refer to figure 1 for pressure switch wiring and terminal identification.

Table of Contents