COOLING OPERATION
This product utilizes a 2-stage cooling indoor thermostat. With a
call for first stage cooling (Yl), the outdoor fan and low capacity
compressor are energized. If low capacity cannot satisfy cooling
demand, high capacity is energized (Yl and Y2 or just Y2) by the
second stage of indoor thermostat. After second stage is satisfied,
the unit returns to low-capacity operation until first stage is
satisfied or until second stage is required again. When both first
stage and second stage cooling are satisfied, the compressor will
shut off.
NOTE: If unit has not operated within the past 12 hr, or following
a unit power-up, upon the next thermostat high- or low-speed
demand, unit operates for a minimum of 5 minutes on high speed.
NOTE: Outdoor fan motor will continue to operate for one
minute after compressor shuts off, when outdoor ambient is greater
than 100°F.
NOTE: When two-speed unit is operating in low-capacity cool-
ing, system vapor (suction) pressure will be higher than a standard
single-speed system or high-speed operation. This normal opera-
tion is due to the reduced capacity operating with typically larger
indoor and outdoor coils.
HEATING OPERATION
This product utilizes a 3-stage heating indoor thermostat. With a
call for first stage heating (Y1), the outdoor fan and low capacity
compressor are energized. If low capacity cannot satisfy heating
demand, high capacity is energized (Y1 and Y2) by the second
stage of the indoor thermostat. Auxiliary or back up heat is
controlled by third stage (W1). After second stage of heat is
satisfied, the unit returns to low capacity operation until first stage
is satisfied or until second stage is required again. When both first
stage and second stage heating are satisfied, the compressor will
shut off.
NOTE: If unit has not operated within the past 12 hr, or following
a unit power-up, upon the next thermostat high- or low-speed
demand, unit operates for a minimum of 5 minutes on high speed.
STATUS FUNCTION LIGHTS
A system control STATUS function light is located on the outdoor
unit control board. (See Fig. 14.) The STATUS light provides
indication signals for several system operations. See Table 4 for
codes and definitions. Table 4 also provides the order of signal
importance.
NOTE: Only one code will be displayed on the outdoor unit
control board (the most recent, with the highest priority).
FACTORY DEFAULTS
Factory defaults have been provided in the event of failure of
outdoor air thermistor and/or outdoor coil thermistor. Refer to
Table 6 for default and function.
ONE MINUTE SPEED CHANGE TIME DELAY
When compressor changes speeds from high to low or low to high,
there is a 1-minute time delay before compressor restarts. The
outdoor fan motor remains running.
COMPRESSOR OPERATION
When the compressor operates in second stage operation, the
motor rotates clockwise. Both the lower and upper pistons are
eccentric with the rotating crankshaft, and both compress refrig-
erant. When the compressor operates in single stage operation the
motor reverses direction (rotates counter-clockwise). The lower
piston becomes idle and the upper piston compresses refrigerant.
During single capacity operation the “start” and “run” wind-
ings are reversed.
Table 3—Required Liquid-Line Temperature (°F)
LIQUID PRESSURE AT
SERVICE VALVE
(PSIG)
REQUIRED SUBCOOLING TEMPERATURE
(°F)
5 101520
174 56 51 46 41
181 58 53 48 43
188 61 56 51 46
195 63 58 53 48
202 65 60 55 50
209 67 62 57 52
216 69 64 59 54
223 71 66 61 56
230 73 68 63 58
237 75 70 65 60
244 77 72 67 62
251 79 74 69 64
258 81 76 71 66
265 82 77 72 67
272 84 79 74 69
279 86 81 76 71
286 88 86 78 73
293 89 84 79 74
300 91 86 81 76
307 93 88 83 78
314 94 89 84 79
321 96 91 86 81
328 97 92 87 82
335 99 94 89 84
342 100 95 90 85
349 102 97 92 87
356 103 98 93 88
363 105 100 95 90
370 106 101 96 91
377 107 102 97 92
384 109 104 99 94
391 110 105 100 95
398 112 107 102 97
405 113 108 103 98
412 114 109 104 99
419 115 110 105 100
426 117 112 107 102
433 118 113 108 103
440 119 114 109 104
447 120 115 110 105
454 122 117 112 107
461 123 118 113 108
468 124 119 114 109
475 125 120 115 110
482 126 121 116 111
489 127 122 117 112
496 129 124 119 114
503 130 125 120 115
510 131 126 121 116
517 132 127 122 117
524 133 128 123 118
531 134 129 124 119
538 135 130 125 120
545 136 131 126 121
552 137 132 127 122
559 138 133 128 123
566 139 134 129 124
573 140 135 130 125
580 141 136 131 126
587 142 137 132 127
594 143 138 133 128
601 144 139 134 129
608 145 140 135 130
8
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