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
10
15
20
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
