Therma-Stor Products Group Ultra-Aire 100V owner manual 7.6B Replacing a Burned Out Compressor

FOR HVAC INSTALLER AND HOMEOWNER

6.Compressor terminal C and overload terminal 1: No continuity indicates a defective overload lead.

7.Overload terminals 1 and 3:

If there is no continuity, the overload may be tripped. Wait

10 minutes and try again. If there is still no continuity, it is defective and must be replaced.

8.Compressor terminal C and compressor case: Continuity indicates a grounded motor. The compressor must be replaced.

9.Disconnect the wires from the run capacitor. Set the ohmmeter to the Rx1 scale. The capacitor is shorted and must be replaced if continuity exists across its terminals. If there is no needle movement with the meter set on the Rx100000 scale, the capacitor is open and must be replaced.

10.Reconnect the wires to the compressor and capacitor. Plug in and turn on the unit. If the compressor fails to start, replace the run capacitor.

11.If the unit still does not start, adding a hard-start kit (relay & capacitor) will provide greater starting torque. If this doesn't work, the compressor has an internal mechanical defect and must be replaced.

7.6B 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.

The following procedure is effective only if the system is monitored after replacing the compressor to insure that the clean up was complete.

1.This procedure assumes that the previously listed compressor motor circuit tests revealed a shorted or open winding. If so, cautiously smell the refrigerant from the compressor service port for the acid odor of a burn out. WARNING: The gas could be toxic and highly acidic. If no acid odor is present, skip down to the section on changing a non-burn out compressor.

2.Remove and properly dispose of the system charge. DO NOT vent the refrigerant indoors or allow it to contact your eyes or skin.

3.Remove the burned out compressor. Use rubber gloves if there is any possibility of contacting the oil or sludge.

4.To facilitate subsequent steps, determine the type of burn out that occurred. If the discharge line shows no evidence of sludge and the suction line is also clean or perhaps has some light carbon deposits, the burn out occurred while the compressor

was not rotating. Contaminants are therefore largely confined to the compressor housing. A single installation of liquid and suction line filter/driers will probably clean up the system. If sludge is evident in the discharge line, it will likely be found in the suction line. This indicates the compressor burned out will running. Sludge and acid have been pumped throughout the system. Several changes of the liquid and suction filter/driers will probably be necessary to cleanse the system.

5.Correct the system fault that caused the burn out. Consult the factory for advice.

6.Install the replacement compressor with a new capacitor and an oversized liquid line filter. In a running burn out, install an oversized suction line filter/drier between the accumulator and compressor. Thoroughly flush the accumulator with refrigerant to remove all trapped sludge and to prevent the oil hole from becoming plugged. A standing burn out does not require a suction line filter/drier.

7.Evacuate the system with a good vacuum pump and accurate vacuum gauge. Leave the pump on the system for at least an hour.

8.Operate the system for a short period of time, monitoring the suction pressure to determine that the suction filter is not becoming plugged. Replace the suction filter/drier if pressure drop occurs. If a severe running burn out has occurred, several filter/driers may have to be replaced to remove all of the acid and moisture.

NOTE: NEVER use the compressor to evacuate the system or any part of it.

7.6C Replacing a Compressor, Nonburn Out

Remove the refrigerant from the system. Replace the compressor and liquid line filter/drier. Charge the system to 50 PSIG and check for leaks. Remove the charge and weigh in the refrigerant quantity listed on the nameplate. Operate the system to verify performance.

7.7 Remote Controls

The Ultra-Aire is controlled by devices mounted on a panel that is remote from the unit. You may or may not have the devices listed below depending on the model of the remote control panel that you purchased. If the Ultra-Aire fails to operate as desired, always check the settings of the controls to insure that they are correct. Check that the controls are receiving 24Vac from the Ultra-Aire. Check the connections between the Ultra-Aire, the control panel, and the field control wiring.

7.7A 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

19 Ultra-Aire 100V Installer’s & Owner’s Manual