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17
COMPRESSOR ROTATION
On 3-phase units with scroll compressors, it is important to be cer-
tain compressor is rotating in the proper direction. To determine
whether or not compressor is rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings.
2. Energize the compressor.
3. The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
NOTE: If the suction pressure does not drop and the discharge
pressure does not rise to normal levels:
4. Note that the evaporator fan is probably also rotating in
the wrong direction.
5. Turn off power to the unit.
6. Reverse any two of the unit power leads.
7. Reapply power to the compressor.
The suction and discharge pressure levels should now move to
their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direction,
the unit makes an elevated level of noise and does not provide
cooling.
See Table 1 for cooling service analysis.
Filter Drier
Replace whenever refrigerant system is exposed to atmo-
sphere. Only use factory specified liquid-line filter driers with
working pressures no less than 650 psig. Do not install a suc-
tion-line filter drier in liquid line. A liquid-line filter drier de-
signed for use with Puron refrigerant is required on every unit.
Condenser Fan Adjustment
See Fig. 20.
1. Shut off unit power supply. Install lockout tag.
2. Remove condenser-fan assembly (grille, motor, and fan).
3. Loosen fan hub setscrews.
4. Adjust fan height as shown in Fig. 20.
5. Tighten setscrews.
6. Replace condenser-fan assembly.
Fig. 20 — Condenser Fan Adjustment
Conduit
0.14 in + 0.0 / -0.03
Table 1 — Cooling Service Analysis
PROBLEM
CAUSE
REMEDY
Compressor and condenser fan will not start
Power failure.
Call power company.
Fuse blown or circuit breaker tripped.
Replace fuse or reset circuit breaker.
Defective thermostat, contactor, transformer, or
control relay.
Replace component.
Insufficient line voltage.
Determine cause and correct.
Incorrect or faulty wiring.
Check wiring diagram and rewire correctly.
Thermostat setting too high.
Lower thermostat setting below room temperature.
Compressor will not start but condenser
fan runs
Faulty wiring or loose connections in compressor
circuit.
Check wiring and repair or replace.
Compressor motor burned out, seized, or internal
overload open.
Determine cause. Replace compressor.
Defective run/start capacitor, overload, start
relay.
Determine cause and replace.
One leg of three-phase power dead.
Replace fuse or reset circuit breaker. Determine
cause.
Compressor cycles (other than normally
satisfying thermostat)
Refrigerant overcharge or undercharge.
Recover refrigerant, evacuate system, and
recharge to nameplate.
Defective compressor.
Replace and determine cause.
Insufficient line voltage.
Determine cause and correct.
Blocked condenser.
Determine cause and correct.
Defective run/start capacitor, overload, or start
relay.
Determine cause and replace.
Defective thermostat.
Replace thermostat.
Faulty condenser, fan motor, or capacitor.
Replace.
Restriction in refrigerant system.
Locate restriction and remove.
Compressor operates continuously
Dirty air filter.
Replace filter.
Unit undersized for load.
Decrease load or increase unit size.
Thermostat set too low.
Reset thermostat.
Low refrigerant charge.
Locate leak; repair and recharge.
Leaking valves in compressor.
Replace compressor.
Air in system.
Recover refrigerant, evacuate system, and
recharge.
Condenser coil dirty or restricted.
Clean coil or remove restriction.
Excessive head pressure
Dirty air filter.
Replace filter.
Dirty condenser coil.
Clean coil.
Refrigerant overcharged.
Recover excess refrigerant.
Air in system.
Recover refrigerant, evacuate system, and
recharge.
Condenser air restricted or air short-cycling.
Determine cause and correct.
Summary of Contents for Puron R-410A
Page 29: ...29 Fig 44 RTU Open Overlay for Economizer Wiring ...
Page 30: ...30 Fig 45 VFD Overlay for W2770 Controller Wiring ...
Page 50: ...50 Fig 63 50KC Typical Unit Wiring Diagram Power 06A 208 230 3 60 ...
Page 51: ...51 Fig 64 50KC Unit Wiring Diagram Control A06 ...
Page 77: ...77 Fig C Unit Wiring Diagram Power for Sizes A04 and A06 208 230 1 60 ...
Page 78: ...78 Fig D Unit Wiring Diagram Power for Size A05 208 230 1 60 ...
Page 79: ...79 Fig E Unit Wiring Diagram Power for Sizes A04 A06 208 230 3 60 460 3 60 575 3 60 ...