HP H4H3 SEQUENCE OF OPERATION

INSTALLATION INSTRUCTIONS							3-phase R-410A Split System Heat Pump
Figure 14			R-410A Required Liquid Line Temperature (°F) - Cooling Mode
Measured Liquid		Rating Plate (required)					Measured Liquid		Rating Plate (required)
	Subcooling Temperature (°F)							Subcooling Temperature (°F)
Pressure (psig)							Pressure (psig)
	6	8	10	12	14	16		6	8	10	12	14	16
251	78	76	74	72	70	68	364	104	102	100	98	96	94
259	80	78	76	74	72	70	374	106	104	102	100	98	96
266	82	80	78	76	74	72	384	108	106	104	102	100	98
274	84	82	80	78	76	74	395	110	108	106	104	102	100
283	86	84	82	80	78	76	406	112	110	108	106	104	102
291	88	86	84	82	80	78	416	114	112	110	108	106	104
299	90	88	86	84	82	80	427	116	114	112	110	108	106
308	92	90	88	86	84	82	439	118	116	114	112	110	108
317	94	92	90	88	86	84	450	120	118	116	114	112	110
326	96	94	92	90	88	86	462	122	120	118	116	114	112
335	98	96	94	92	90	88	474	124	122	120	118	116	114
345	100	98	96	94	92	90

SEQUENCE OF OPERATION

A. COOLING MODE

On a call for cooling, the thermostat makes circuits R-O, R-Y, and R-G. Circuit R-O energizes reversing valve, switching it to cooling position. Circuit R-Y energizes contactor, starting outdoor fan motor and compressor. Circuit R-G energizes indoor unit blower relay, starting indoor blower motor.

When thermostat is satisfied, its contacts open, de-energizing contactor and blower relay. Compressor and motors stop.

NOTE: If indoor unit is equipped with a time-delay relay circuit, the blower runs an additional length of time to increase system efficiency. (Applies to both cooling and heating modes.)

NOTE: Low ambient cooling feature allows unit to operate safely in cooling mode down to 0_ F outdoor ambient.

B. HEATING MODE

On a call for heating, the thermostat makes circuits R-Y and R-G (circuit R-O is NOT made, and the reversing valve stays in the de-energized, heating position). Circuit R-Y energizes contactor, starting outdoor fan motor and compressor. Circuit R-G energizes indoor blower relay, starting blower motor. If the room temperature continues to fall, circuit R-W2 is made through the second-stage room thermostat bulb. Circuit R-W2 energizes a sequencer, bringing on the first bank supplemental electric heat and providing electrical potential to the second heater sequencer (if used). If outdoor temperature falls below the setting of the outdoor thermostat (field-installed option), contacts close to complete the circuit and bring on the second bank of supplemental electric heat.

When the thermostat is satisfied, its contacts open, de-energizing contactor, blower relay, and sequencer. Compressor, motors, and heaters stop.

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