Start-Up Procedure; Refrigerant Charge; Sequence Of Operation - International comfort products N4A3 Series Installation Instructions Manual

INSTALLATION INSTRUCTIONS

START-UP PROCEDURE

1. Set indoor thermostat selector switch to OFF.
2. Turn ON all electrical disconnect devices.
3. If unit has a crankcase heater, energize the heater
and wait 24 hours before proceeding.

REFRIGERANT CHARGE

Outdoor units are shipped with a refrigerant charge to
match a specific indoor coil and 15 feet of refrigerant line.
If shorter or longer refrigerant lines or a different indoor
coil are used, the charge will have to be adjusted.
For different line lengths, add or remove charge based on
0.6 ounces charge per foot of difference. For example, a
25 foot line set is 10 feet longer than the specified 15 feet.
Add 0.6 ounces charge for each of the extra 10 feet:
10 x 0.6 = 6.0 ounces additional charge
This outdoor unit is designed for use only with indoor coils
that utilize a TXV refrigerant metering device. With an
indoor TXV, use the subcooling method to make final
charge adjustments:
NOTE: Only use subcooling charging method when
S outdoor ambient temperature is between 70_F and 100_F
S indoor temperature is between 70_ and 80_F
S line set is less that 80 feet.
1. Operate unit a minimum of 15 minutes before
checking charge.
NOTE: If outdoor unit has a 2-speed fan motor,
motor will operate in low speed when outdoor
ambient temperature is below 82 °F. Pull one of the
yellow low voltage wires off the fan control and the
unit will default to high speed fan for servicing.
Reconnect wire after servicing.
Figure 10
Measured Liquid
Subcooling Temperature (°F)
Pressure (psig)
6
251 78
259 80
266 82
274 84
283 86
291 88
299 90
308 92
317 94
326 96
335 98
345 100

SEQUENCE OF OPERATION

With power supplied to indoor and outdoor units,
transformer is energized.
On a call for cooling, the thermostat makes circuits R-Y
and R-G. Circuit R-Y energizes contactor, starting
outdoor fan motor and compressor. Circuit R-G
energizes indoor unit blower relay, starting indoor blower
motor.
421 01 5101 00
R-410A Required Liquid Line Temperature (°F)
Rating Plate (required)
8 10 12 14
76 74 72 70
78 76 74 72
80 78 76 74
82 80 78 76
84 82 80 78
86 84 82 80
88 86 84 82
90 88 86 84
92 90 88 86
94 92 90 88
96 94 92 90
98 96 94 92
R-410A Split System Air Conditioner
4. Set indoor thermostat at desired temperature. Be
sure setpoint is below indoor ambient temperature
or thermostat will not call for cooling.
5. Set indoor thermostat selector switch to COOL.
Operate unit for minimum 15 minutes, then check
the system refrigerant charge.
2. Measure liquid service valve pressure by attaching
an accurate gauge to service port.
3. Measure liquid line temperature by attaching an
accurate thermistor type sensor or electronic
thermometer to liquid line near outdoor coil.
4. Refer to unit rating plate for required subcooling
temperature.
5. Refer to Figure 10. Find the required liquid line
temperature where the rating plate subcooling
temperature intersects measured liquid service
valve pressure.
6. If the measured liquid line temperature is higher
than the chart number, add refrigerant to lower the
measured temperature.
NOTE: When adding refrigerant, charge in liquid form,
using a flow restricting device, into the suction port.
If the measured liquid line temperature is lower than the
chart number, reclaim refrigerant to raise the measured
temperature.
Tolerance is | 3 °F.
Measured Liquid
Pressure (psig)
16
68 364 104
70 374 106
72 384 108
74 395 110
76 406 112
78 416 114
80 427 116
82 439 118
84 450 120
86 462 122
88 474 124
90
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.
Rating Plate (required)
Subcooling Temperature (°F)
6 8 10 12 14
102 100 98 96
104 102 100 98
106 104 102 100
108 106 104 102
110 108 106 104
112 110 108 106
114 112 110 108
116 114 112 110
118 116 114 112
120 118 116 114
122 120 118 116
16
94
96
98
100
102
104
106
108
110
112
114
11