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HPXA16 SERIES
Table 6
HPXA16 Normal Operating Pressures
COOLING (Liquid ±10 & Vapor ±5 psig)*
°F (°C)**
−024
−036
−048
−060
°F (°C)**
Liq
Vap
Liq
Vap
Liq
Vap
Liq
Vap
First Stage (Low Capacity)
65 (18.3)
217
143
227
142
222
140
225
140
75 (23.9)
250
145
262
145
258
143
259
142
85 (29.4)
291
147
305
146
298
145
293
146
95 (35.0)
336
149
352
148
343
147
356
147
105 (40.6)
386
151
403
152
402
147
408
147
115 (49.0)
440
153
458
155
452
152
455
151
Second Stage (High Capacity)
65 (18.3)
222
143
244
136
232
134
249
126
75 (23.9)
256
145
282
139
266
136
289
134
85 (29.4)
302
145
325
142
309
139
330
140
95 (35.0)
349
147
377
144
359
142
378
143
105 (40.6)
403
149
428
146
410
144
433
146
115 (49.0)
464
152
488
148
468
147
492
149
*These are most−popular−match−up pressures. Indoor match
up, indoor air quality, and indoor load cause pressures to vary.
**Temperature of the air entering the outside coil.
Table 7
HPXA16 Normal Operating Pressures
HEATING (Liquid ±10 & Vapor ±5 psig)
°F (°C)**
−024
−036
−048
−060
°F (°C)**
Liq
Vap
Liq
Vap
Liq
Vap
Liq
Vap
First Stage (Low Capacity)
40 (4.4)
321
99
296
95
315
97
319
93
50 (10)
340
120
310
112
330
114
335
111
Second Stage (High Capacity)
20 (−7.0)
273
68
277
60
294
60
300
57
30 (−1.0)
296
80
296
74
303
75
312
70
40 (4.4)
321
95
321
88
314
90
323
83
50 (10)
341
115
341
104
325
106
339
97
*These are most−popular−match−up pressures. Indoor match
up, indoor air quality, and indoor load cause pressures to vary.
**Temperature of the air entering the outside coil.
4. Use the same digital thermometer used to check
outdoor ambient temperature to check liquid line
temperature. Verify the unit charge using the approach
method.
5. The difference between the ambient and liquid
temperatures should match values given in table 8. If
the values don’t agree with the those in table 8, add
refrigerant to lower the approach temperature or
recover refrigerant from the system to increase the
approach temperature.
Table 8
Approach Values for Charging
Model Number
Second Stage (High Capacity) Ap-
proach Temperature Liquid Line Temp. −
Outdoor Ambient °F (°C)
HPXA16−024
4.0 + 1 (2.2 + .5)
HPXA16−036
7.0 + 1 (3.9 + .5)
HPXA16−048
8.0 + 1 (4.4 + .5)
HPXA16−060
10.0 + 1 (5.6 + .5)
System Operation
The outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is in the
ON
position, the indoor blower operates continu-
ously.
Thermostat Operation
Some indoor thermostats incorporate isolating contacts
and an emergency heat function (which includes an amber
indicating light). The thermostat is not included with the
unit and must be purchased separately.
Emergency Heat (Amber Light)
An emergency heat function is designed into some room
thermostats. This feature is applicable when isolation of the
outdoor unit is required, or when auxiliary electric heat is
staged by outdoor thermostats. When the room thermostat is
placed in the emergency heat position, the outdoor unit con-
trol circuit is isolated from power and field-provided relays by-
pass the outdoor thermostats. An amber indicating light si-
multaneously comes on to remind the homeowner that he is
operating in the emergency heat mode.
Emergency heat is usually used during an outdoor unit
shutdown, but it should also be used following a power out-
age if power has been off for over an hour and the outdoor
temperature is below 50°F (10°C). System should be left in
the emergency heat mode at least six hours to allow the
crankcase heater sufficient time to prevent compressor
slugging.
Filter Drier
The unit is equipped with a large−capacity biflow filter drier
which keeps the system clean and dry. If replacement is
necessary, order another of like design and capacity. The
replacement filter drier must be suitable for use with
HFC−410A refrigerant.
