FOR HVAC INSTALLER ONLY
5.6A Replacing a Burned out Compressor
The refrigerant and oil mixture in a compressor is chemically very stable under normal operating conditions. However, when an electrical short occurs in the compressor motor, the resulting high temperature arc causes a portion of the refrigerant oil mixture to break down into carbonaceous sludge, a very corrosive acid and water. These contaminants must be carefully removed otherwise even small residues will attack replacement compressor motors and cause failures.
Test the failed compressor oil with a test kit. If it indicates a burn- out, follow EPA regulations for disposing of the old refrigerant and oil. Follow standard procedures for replacing a
5.6B Replacing a Compressor-Nonburn Out
Dispose of the old refrigerant per EPA guidelines. Replace the compressor and liquid line filter/drier. Weigh in the refrigerant quantity listed on the nameplate.
5.7 Humidity Control
The humidity control is an adjustable switch that closes when the relative humidity of the air in which it is located rises to the dial set point. It opens when the RH drops 4 to 6% below the set point.
5.8 Defrost Thermostat
The defrost thermostat is attached to the refrigerant suction tube between the accumulator and compressor. It will automatically shut the compressor off if the low side refrigerant temperature drops due to excessive frost formation on the evaporator coil. The blower will continue to run, causing air to flow through the evaporator coil and melt the ice. When the ice has melted, the evaporator temperature will rise and the thermostat will restart the compressor.
5.9 Condensate Pump
Condensate is automatically pumped to a remote location when the water level in the pump’s reservoir rises to close the float switch.
The pump also contains a safety float switch. If the pump fails, this switch opens the compressor control circuit and stops water production before the reservoir overflows. The compressor will stop, but the blower will not.
5.10 Relay
The relay provides power to the compressor via the black wire. Current passes through relay contacts between terminals 4 and 6. The contacts are closed when power is applied to relay terminals
0 and 1 by the dehumidistat, pump safety, defrost control and low pressure control are all closed.
If there is no continuity between terminals 4 and 6 when power is applied to terminal 0 and 1 by the control circuit, the relay is defective and must be replaced. The relay is also defective if there is continuity between 4 and 6 when no power is applied to 0 and 1.
5.11 Low Pressure Control
If the low side refrigerant pressure drops to 15 PSIG, the low pressure control opens; this opens the blower circuit and the control circuit that controls the compressor. It is an automatically reset control; it will close if the pressure rises to 37 PSIG. It’s primary function is to prevent damage to the compressor if a leak develops in the refrigeration system.
6 | Santa Fe Rx Installer’s & Owner’s Manual |
