Daikin M Series Service And Troubleshooting page 10

SYSTEM OPERATION
Cooling
1. Thermostat calls for cooling.
2. When the thermostat call is for cooling, the
compressor and outdoor fan are energized .
3. The indoor blower will energize approximately 6
seconds later.
4. The unit delivers cooling to the conditioned space
until the thermostat is satisfied.
5. The compressor and outdoor fan will be de-
energized when the thermostat opens.
6. The indoor blower continues to run at low cool speed
for approximately 60 seconds after the thermostat
is satisfied. This allows additional cooling from the
indoor coil to be transferred to the conditioned space.
Then, the indoor blower is de-energized.
NOTE: A 180-second anti-short cycle is integral to the
control and prevents recycling of the compressor
Defrost Cycle
NOTE: The defrost board is equipped with a jumper
for SmartShift™ defrost technology operation. This
operation turns the compressor off for 30 seconds at
defrost initiation and termination. The unit is factory
shipped for SmartShift™ defrost technology operation.
To operate unit at rated efficiencies, move the jumper
on the defrost board from "DLY" to "NORM".
During operation, the power to the circuit board is
controlled by a temperature sensor, which is clamped to a
feeder tube entering the outdoor coil. Defrost timing periods
of 30, 60 and 90 minutes may be selected by setting the
circuit board jumper to 30, 60 and 90 respectively.
Accumulation of time for the timing period selected starts
when the sensor closes (approximately 30°F), and when
the wall thermostat calls for heat. At the end of the timing
period, the unit's defrost cycle will be initiated provided the
sensor remains closed.
Upon a call for defrost, the blower will continue to run
and the defrost board will send a W1 signal to the ignition
control. At the same time, the compressor will stop for
30 seconds, if the SmartShift™ defrost technology delay
feature is selected on the defrost board. At this time,
the reversing valve shifts from heat to cool position and
condenser fans shut off. The inducer motor will immediatly
energize for a 15 second prepurge.
A 7-second trial for ignition begins by energizing the low
and high stages of the gas valve along with this spark
ignition. Main burners light and control detects presence
of flame. The compressor (after its 30/OFF second delay)
restarts in cooling mode to defrost the condensor coil.
When the sensor opens (approximately 60°F), the
defrost cycle is terminated and the timing period is reset.
If the defrost cycle is not terminated due to the sensor
temperature, a twelve minute override interrupts the unit's
defrost period. At this time the W1 signal is removed from
the ignition control board, the compressor will stop for a 30
second SmartShift™ defrost technology delay (if selected)
and the reversing valve slides back to its normal heat
position.
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