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C-Three Phase Scroll Compressor Voltage Phasing
Three phase scroll compressors must be phased
sequentially to ensure correct compressor and blower
rotation and operation. Compressor and blower are wired
in phase at the factory. Power wires are color-coded as
follows: line 1-red, line 2-yellow, line 3-blue.
1- Observe suction and discharge pressures and
blower rotation on unit start-up.
2- Suction pressure must drop, discharge pressure must
rise, and blower rotation must match rotation marking.
If pressure differential is not observed or blower rotation is
not correct:
3- Disconnect all remote electrical power supplies.
4- Reverse any two field-installed wires connected to
the line side of S48 disconnect or TB13 terminal strip.
Do not reverse wires at blower contactor.
5- Make sure the connections are tight.
Discharge and suction pressures should operate at
their normal start‐up ranges.
D-R410A Refrigerant
Units charged with R410A refrigerant operate at much
higher pressures than R22. The expansion valve and
liquid line drier provided with the unit are approved for use
with R410A. Do not replace them with components
designed for use with R22.
R410A refrigerant is stored in a pink cylinder.
IMPORTANT
Mineral oils are not compatible with R410A. If oil
must be added, it must be a polyol ester oil.
Manifold gauge sets used with systems charged with
R410A refrigerant must be capable of handling the higher
system operating pressures. The gauges should be rated
for use with pressures of 0-800 on the high side and a low
side of 30” vacuum to 250 psi with dampened speed to
500 psi. Gauge hoses must be rated for use at up to 800
psi of pressure with a 4000 psi burst rating.
E-Refrigerant Charge and Check
WARNING-Do not exceed nameplate charge under
any condition.
This unit is factory charged and should require no further
adjustment. If the system requires charge,
reclaim the
charge,
evacuate the system,
and
add required
nameplate charge.
If weighing facilities are not available, or to check the
charge, use the following procedure:
1- Attach gauge manifolds and operate unit at full CFM
in cooling mode until system stabilizes
(approximately five minutes). Make sure all outdoor
air dampers are closed.
2- Check each system separately with all stages
operating.
3- Use a thermometer to accurately measure the
entering water temperature at the strainer. See
figure 33.
4- Apply the water temperature to appropriate table 10
through 17 to determine normal operating pressures.
5- Compare the normal operating pressures to the
pressures 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.
6- If discharge pressure is high, remove refrigerant from
the system. If discharge pressure is low, add
refrigerant to the system.
Add or remove charge in increments.
Allow the system to stabilize each time
refrigerant is added or removed.
7- Operate the unit in heating mode until system
stabilizes (approximately five minutes).
8- Apply the water temperature to appropriate table 10
through 17 to determine normal operating pressures.
Use steps 5 and 6 to adjust refrigerant.
TABLE 10
SW 036 COOLING OPERATING PRESSURES
Entering
Water Temp
Discharge
+10 psig
S 5
psig
59
F
245
140
77
F
312
144
86
F
339
148
TABLE 11
SW 036 HEATING OPERATING PRESSURES
Entering
Water Temp
Discharge
+10 psig
S 5
psig
32
F
291
77
50
F
321
106
68
F
352
137
