Page 47
XP14 SERIES
SEQUENCE OF OPERATIONS
This is the sequence of operation for XP14 series units.
The sequence is outlined by numbered steps which
correspond to circled numbers on the adjacent diagram.
The steps are identical for both cooling and first stage
heating demand with the exception reversing valve L1 is
energizedduringcoolingdemandandde-energizedduring
heating demand.
NOTE- Transformer in indoor unit supplies power (24 VAC)
to the thermostat and outdoor unit controls.
COOLING:
Internal thermostat wiring energizes terminal O by cooling
mode selection, energizing the reversing valve L1.
1. Demand initiates at Y1 in the thermostat.
2. 24VAC energizes compressor contactor K1.
3. K1‐1 N.O. closes, energizing compressor (B1) and
outdoor fan motor (B4).
END OF COOLING DEMAND:
1. Demand is satisfied. Terminal Y1 is de‐energized.
2. Compressor contactor K1 is de‐energized.
3. K1‐1 opens and compressor (B1) and outdoor fan
motor (B4) are de‐energized and stop immediately.
FIRST STAGE HEAT:
Internal thermostat wiring de-energizes terminal O by
heating mode selection, de-energizing the reversing valve
L1.
See steps 1, 2 and 3.
END OF FIRST STAGE HEAT:
See steps 4, 5 and 6.
DEFROST MODE:
When a defrost cycle is initiated, the control energizes the
reversing valve solenoid and turns off the condenser fan.
The control will also put 24VAC on the “W1” (auxiliary heat)
line. The unit will stay in this mode until either the coil
sensor temperature is above the selected termination
temperature, the defrost time of 14 minutes has been
completed, or the room thermostat demand cycle has
been satisfied. (If the temperature select shunt is not
installed, the default termination temperature will be 90°F.)
If the room thermostat demand cycle terminates the cycle,
the defrost cycle will be held until the next room thermostat
demand cycle. If the coil sensor temperature is still below
the selected termination temperature, the control will
continue the defrost cycle until the cycle is terminated in
one of the methods mentioned above. If a defrost is
terminated by time and the coil temperature did not remain
above 35°F (2°C) for 4 minutes the control will go to the
30-minute Time/Temperature mode.
Start-Up and Performance Checklist
Job Name Job no. Date
Job Location City State
Installer City State
Unit Model No. Serial No. Service Technician
Nameplate Voltage
Rated Load Ampacity Compressor Amperage:
Maximum Fuse or Circuit Breaker
Electrical Connections Tight? Indoor Filter clean? Supply Voltage (Unit Off)
Indoor Blower RPM S.P. Drop Over Indoor (Dry) Outdoor Coil Entering Air Temp.
Vapor Pressure;
Refrigerant Lines: Leak Checked? Properly Insulated? Outdoor Fan Checked?
Service Valves: Fully Opened? Caps Tight? Voltage With Compressor Operating
SEQUENCE OF OPERATION
Calibrated?
THERMOSTAT
Properly Set? Level?
Heating Correct? Cooling Correct?
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