NOTE: This sequence of operation assumes that 2 thermo- stats control units 38AH124 or 134 with one thermostat con- trolling each module.
If compressor A1 is insufficient for the cooling require- ments, the thermostat second stage closes, which opens the liquid line solenoid valve
ALL UNITS Ð When the fan switch is set for automatic (AUTO) operation, the
Restart After Stoppage by Safety Control Ð The
Stoppage by
The compressor motor overcurrent protectors are manual- reset circuit breakers. Reset of control circuit may also be necessary.
Independent Refrigerant Circuit Controls Ð Each refrigeration circuit is controlled by independent circuitry. Therefore, it is possible to maintain partial cooling capabil- ity even if one compressor is inoperable.
NOTE: The
NOTE: Black denotes closed contacts.
Fig. 47 Ð Timer Cycle
Unit Control Box Ð (See Fig. 48.) Viewed facing com- pressors, the control box is at left end of the unit. All in- coming power enters through the control box. The control box contains power components and electronic controls. Outer panels are hinged and latched for easy opening. Remove screws to remove inner panels. Outer panels can be held open for service and inspection by using door retainer on each panel. Remove bottom pin from door retainer assembly, swing re- tainer out horizontally, and engage pin in one of the retainer ears and the hinge assembly.
Condenser Fans Ð Each fan is supported by a formed wire mount bolted to fan deck and covered with a wire guard. The exposed end of fan motor shaft is protected from weather by grease. If fan motor must be removed for service or re- placement, be sure to regrease fan shaft, and reinstall fan guard. For proper performance, fan should be 7¤8 in. (22 mm) below top of venturi on the fan deck to top of the fan hub for
IMPORTANT: Check for proper fan rotation (clock- wise viewed from above). If necessary to reverse, switch leads.
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