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Three-Phase Compressor Rotation
Three phase scroll compressors must be phased sequen
tially to ensure that the compressor rotates and operates
correctly. When the compressor starts, a rise in discharge
and drop in suction pressures indicate proper compressor
phasing and operation. If discharge and suction pressures
do not perform normally, follow the steps below to correctly
phase in the unit.
1 - Disconnect the power to the unit.
2 - Reverse any two field power leads to the unit.
3 - Reconnect the power to the unit.
The discharge and suction pressures should operate with
in their normal start up ranges.
NOTE - The compressor's noise level will be significantly
higher when the phasing is incorrect. The compressor will
not provide cooling when the unit is not correctly phased.
Continued backward operation of the compressor to due to
incorrect phasing will cause the compressor to cycle on in
ternal protector.
Charging
Units are shipped with a holding charge of dry air and/or
helium. which must be removed before the unit is evacu
ated and charged with refrigerant. In new installations,
the recommended and most accurate method of charg
ing is to weigh the refrigerant into the unit as outlined in
table 4 and the following procedure.
Weighing in the Charge
(TXV Systems, < 60°F Outdoor Temperature)
1 - Recover the refrigerant from the unit.
UNIT MODEL
MATCHED
NUMBER
INDOOR UNIT
HP29-090-2
HP29 090 2
CB17/CBH17 95
CB17/CBH17-95
HP29-120-2
HP29 120 2
CB17/CBH17-135
CB17/CBH17 135
* If line length is greater than 25 feet (7.62 m), add this amount. If line length is less than 25 feet (7.62 m), subtract this amount.
NOTE - Refrigerant line sets should not be longer than 100 feet (30.5 m). Refrigerant line losses deduct from the net capacity of the sys
tem. Additional refrigerant required for such systems may also upset the refrigerant to oil ratio.
Outdoor Coil
Entering Air
Temperature
65°F (18°C)
75°F (24°C)
85°F (29°C)
95°F (35°C)
105°F (41°C)
115°F (46°C)
* HP29-090 tested with CB17/CBH17-95V. **HP29-120 tested with CB17/CBH17-135V.
TABLE 4
HCFC 22 FOR 25 FEET
(7.6 m) OF LINE
23 lb
23 lbs. (10.4 kg)
31 lbs (14 1 kg)
31 lbs. (14.1 kg)
TABLE 5
NORMAL OPERATING PRESSURES
HP29-090*
HP29-090*
Discharge
+ 10 psig
188
216
248
283
319
360
Page 18
2 - Conduct a leak check, then evacuate as previously
outlined.
3 - Weigh in the factory charge as shown on the outdoor
unit's rating plate.
Checking Charge Using Normal Operating Pressures
If weighing facilities are not available, or if charge needs
to be checked, use the following method:
1 - Attach gauge manifolds and operate unit in cooling
mode until system stabilizes (approximately five min
utes).
2 - Use a thermometer to accurately measure the outdoor
ambient temperature.
3 - Apply the outdoor temperature to table 5 to determine
normal operating pressures.
4 - Compare the normal operating pressures to the pres
sures obtained from the gauges. Minor variations in
these pressures may be expected due to differences in
installations. Significant differences could mean that
the system is not properly charged or that a problem
exists with some component in the system. Correct
any system problems before proceeding.
5 - Use approach method to confirm the readings, or ad
just the refrigerant charge.
Charge Verification
The refrigerant charge can be verified using the approach
method if the outdoor ambient temperature is 60°F or
above. If the outdoor ambient temperature is below 60°F,
you must weigh the refrigerant into the unit to ensure prop
er charging.
LIQUID LINE
DIAMETER
5/8 in. (16 mm)
(10 4 k )
3/4 in. (19 mm)
5/8 in. (16 mm)
3/4 in. (19 mm)
HP29-120**
Vapor
Discharge
+ 5 psig
+ 10 psig
69
71
72
74
76
78
ADJUSTMENT PER
FOOT (.3 m) OF LINE*
1.8 oz. (51g)
2.6 oz. (74g)
1.8 oz. (51g)
2.6 oz. (74g)
HP29-120**
Vapor
+ 5 psig
180
64
206
66
236
67
269
69
304
70
345
72
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