Daikin DP14UM Service Instructions Manual page 6

SYSTEM OPERATION
4. The continuous fan operation will function while the
control is in heat mode lockout.
Cool Mode
1. When the thermostat calls for cooling ("Y"), the
control energizes the cooling speed fan after a 7
second on delay. The control provides a 3 minute
anti-short cycle protection for the compressor. If
the compressor has been off for 3 or more minutes,
the compressor immediately energizes when the
thermostat calls for cool. If the compressor has not
been off for at least 3 minutes when a call for cool
occurs, the control waits until 3 minutes has elapsed
from the time the compressor was last de-energized
before re-energizing the compressor.
2. When the thermostat removes the call for cooling
("Y") the compressor is deenergized and the control
deenergizes the cooling speed fan after a cooling off
delay period of 60 seconds.
Note: A call for cooling has priority over continuous fan. If
G is energized while Y is energized, during the cooling fan
on delay, the fan will remain off until the delay is over.
Note: The cooling fan operation will continue to function
while the control is in heat lockout.
Note: If a call for heat exist with a call for cooling, the call
for heat shall proceed as normal except the fan remains
energized on cool speed.
Heat Mode
The normal operational sequence in heating mode is as
follows:
• R and W thermostat contacts close, initiating a call for
heat.
• Integrated control module performs safety circuit
checks.
• Pressure Sensor Verification: The control operates the
inducer in a manner to verify the pressure sensor null
value and span operation are within specification. If
the system is operating correctly, this test takes only a
few seconds. If the system is not functioning properly,
the control times out after a maximum 90 seconds and
displays the proper fault code.
• Induced draft blower is energized for 30 second
prepurge.
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• The control energizes the gas valve and spark igniter. If
flame is not established within 4 seconds, the gas valve
and spark igniter is de-energized and the control goes
to an inter-purge. If the flame is established, the spark
igniter is de-energized and the control goes to heat
blower on delay.
• Heat Blower On Delay – The control waits for 30 second
heat fan on delay and then energizes the indoor blower
heat speed. If the blower is already energized by a
continuous fan call, the on delay is skipped and control
goes to heat fan speed.
• STEADY HEAT – Control inputs are continuously
monitored for ensure limit and pressure switches are
closed, flame is established and the thermostat call for
heat remains.
• POST PURGE – When the thermostat demand for heat
is satisfied, the control immediately de-energizes the
gas valve. The inducer output remains on for a 30
second post-purge period.
• Heat Blower Off Delay – The indoor blower motor is
de-energized after the selected blower off delay time.
Blower timing begins when the thermostat is satisfied.