Daikin DP14U Series, Installation Instructions Manual

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8.  The unit delivers heat to the conditioned space until the 

thermostat is satisfied; integrated control module monitors 

safety circuits continuously.

9.  R and W thermostat contacts open, completing the call for 

heat; gas valve de-energizes.

10.  Induced draft blower keeps operating for 30-second post 

purge.

11.  Ignition control begins timing the HEAT FAN OFF 

delay. There is an adjustable HEAT FAN OFF delay of 

approximately 90/120/150/180 seconds (factory set at 150).

NOTE:

 This delay allows any additional heat in the heat 

exchanger to be transferred to the conditioned space. After the 

HEAT FAN OFF delay time has elapsed, the blower will de-

energize. 

Cooling 

1.  Thermostat calls for low or high stage cooling.
2.  If the thermostat call is for low stage cooling, the compressor 

and outdoor fan are energized at low stage. If the thermostat 

call is for high stage cooling, the compressor and outdoor 

fan are energized at high stage.

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.

Fan Only

1.  Thermostat calls for FAN ONLY by energizing “G”.
2.  Indoor blower is energized at fan only speed. DP16U 

models are equipped with ECM variable speed motor; the 

fan only blower speed is approximately 75% of the HIGH 

COOL speed for DP16U models.

3.  The indoor blower is immediately de-energized once 

thermostat call for FAN is removed. 

Startup, Adjustments, and Checks

Heating Startup 

This unit is equipped with an electronic ignition device to 

automatically light the main burners. It also has a power vent 

blower to exhaust combustion products.
On new installations, or if a major component has been replaced, 

the operation of the unit must be checked.
Check unit operation as outlined in the following instructions. If 

any sparking, odors, or unusual sounds are encountered, shut 

off electrical power and check for wiring errors, or obstructions in 

or near the blower motors. Duct covers must be removed before 

operating unit.

Burner Limit Control

The burner temperature switch is mounted on the burner 

assembly to monitor the burner box temperature. It is normally 

closed (electrically), auto-reset sensor. An input to the control is 

provided by the normally closed blocked burner switch. An open 

blocked burner switch interrupts current to the gas valve which 

closes the valve. This switch guards against the burner flames not 

being properly drawn into the heat exchanger.

Secondary Limit Control

The secondary limit control is located on the top of the blower 

scroll assembly. This control opens when elevated temperatures 

are sensed. Elevated temperatures at the control are normally 

caused by blower failure. The reason for the opening should be 

determined and repaired prior to resetting.
If the power to the unit is interrupted during the heating cycle, 

it may cause the secondary limit to trip. Once the blower 

compartment temperature drops below the limit reset temperature, 

the limit will automatically reset.

Secondary

Control Limit

Back of Unit

Secondary Limit Control

Pre-Operation Checks

1.  Close the manual gas valve external to the unit.
2. 

Turn off the electrical power supply to the unit.

3.  Set the room thermostat to its lowest possible setting.
4.  Remove the heat exchanger door on the side of the unit by 

removing screws.

5.  This unit is equipped with an ignition device which 

automatically lights the main burner. DO NOT try to light 

burner by any other method.

6.  Move the gas control valve switch to the OFF position. Do 

not force.

7. 

Wait five minutes to clear out any gas.