Page 1
HEAT PUMP UNITS
KITS AND ACCESSORIES
Litho U.S.A.
504,587M
3/2014
Supersedes1/2013
REPLACEMENT DEFROST
CONTROL
INSTALLATION INSTRUCTIONS FOR REPLACEMENT DEFROST CONTROL KIT (84W88)
USED WITH VARIOUS HEAT PUMPS
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:
1 - Defrost control (100269-05)
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.
Table 1. Applicable Defrost Controls
Original Defrost Control Replacement Defrost Control
100269-01, -02 and -04
100269-05
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.
To Next Page
Need help?
General
