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If defrost thermostat is in open position, and speedup pins are
shorted (with a flat head screwdriver) for 5 sec and released, a
short defrost cycle will be observed (actual length is dependent
upon the selected Quiet Shift position). When Quiet Shift switch is
in ON position, the length of defrost is 1 minute (30 sec
compressor off period followed by 30 sec of defrost with com-
pressor operation). On return to heating operation, compressor will
again turn off for an additional 30 sec and the fan for 40 sec. When
the Quiet Shift is in OFF position, only a brief 30 sec cycle will be
observed.
If it is desirable to observe a complete defrost in warmer weather,
the thermostat must be closed as follows:
1. Turn off power to outdoor unit.
2. Disconnect outdoor fan motor lead from OF2 on control board
(See Fig. 9.) Tape to prevent grounding.
3. Restart unit in heating mode, allowing frost to accumulate on
outdoor coil.
4. After a few minutes in heating mode, liquid line temperature
should drop below closing point of defrost thermostat (ap-
proximately 30°F).
NOTE: Unit will remain in defrost until defrost thermostat
reopens at approximately 80°F coil temperature at liquid line or
remainder of defrost cycle time.
5. Turn off power to outdoor and reconnect fan motor lead to
OF2 on control board after above forced defrost cycle.
Speedup
Quiet
Pins
Shift
Fig. 9—Defrost Control
CARE AND MAINTENANCE
For continuing high performance and to minimize possible equip-
ment failure, periodic maintenance must be performed on this
equipment.
Leave User's Manual with owner. Explain system operation and
periodic maintenance requirements outlined in manual. Frequency
of maintenance may vary depending upon geographic areas, such
as coastal applications.
7
CESO130076–00
Defrost interval
DIP switches
A99442
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