Industrial Climate Engineering MiniPac ECUA06ACA A2 Series Operation And Installation Manual page 5

to the liquid pressure conditions. The condenser blower always turns on after the compressor and
will cycle frequently during normal operation at low temperatures.
• Condenser motor powered directly through this switch.
• Circuit closes (motor on) at ~400 psi and opens (motor off) at ~245 psi.
• Located in condenser liquid line.
Access Valve
• Port used in service work to sense refrigerant pressures and to add or remove refrigerant.
• Valves are located both in high pressure (discharge) line and low pressure (suction) line.
• 1/4" male flare.
• Automatically closes when test/charging hoses are removed.
• Valve is opened by depressor located in end of test/charging hose.
• Has additional seal cap with "O" ring to prevent leakage.
Filter Drier
• Used to remove contaminants or moisture from refrigerant.
• Located in liquid line.
• Replacement recommended any time sealed refrigeration system is opened for service.
High Pressure Switch (HPS)
• The high pressure switch is mounted on the compressor liquid line. It is electrically connected to
a lockout relay which shuts down the system if the refrigerant pressure rises to 625 PSIG. This
protects the unit if airflow through the condenser is blocked or if the outdoor blower motor fails.
Although the contacts of the high pressure switch close when the refrigerant pressure falls to
approximately 450 PSIG, the system must be manually reset once the lockout relay is activated.
A manual reset is necessary to prevent harmful short-cycling. To reset switch, turn primary power
off, then back on or turn thermostat system switch off, then back on.
• Electrically is part of the low voltage control system.
Low Pressure Switch (LPS)
• The low pressure switch is mounted on the compressor suction line. It is designed to open if the
refrigerant pressure drops to 40 PSIG; it resets when the pressure rises to 60 PSIG. The switch
protects the unit if airflow through the indoor blower is impeded, if the indoor blower motor fails,
or if there is a loss of refrigerant.
• Electrically is part of the low voltage control system.
Evaporator Coil
• Heat exchanger which transfers heat from cabinet air to cold refrigerant in evaporator tubes.
Refrigerant is evaporated to a gas.
• Copper tubes, aluminum fins.
• Rifled tubing, lanced fins.
Condenser Blower and Motor (CBM)
• Single blower used.
• Pulls ambient air through condenser coil and discharges heated air back to ambient.
• Squirrel cage blower design.
• Forward curved blades on wheels.
• Motor drives blower wheel.
• PSC motor design.
• Ball bearings.
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ECUA06 7/2014 new