Therma-Stor Products Group 200 MAX owner manual Compressor/Capacitor Replacement

5.Rotate the blower outlet toward you as you remove it. Use care to avoid hooking wiring, tubing or electrical components.

6.Reassembling with the new blower in the above procedure reversed.

4.6 Compressor/Capacitor Replacement

This compressor is equipped with a two terminal external overload, run capacitor, but no start capacitor or relay (see Fig. 3).

CAUTION-ELECTRICAL SHOCK HAZARD: Electrical power must be present to perform some tests; these tests should be performed by a qualified service person.

4.6A Checking Compressor Motor Circuits

Perform the following tests if the blower runs but the compressor does not with the power switch ON.

1.Turn the power switch OFF and unplug the unit, remove top panel and the cabinet front (6 screws).

2.Plug in the unit and turn the power switch ON. Use a voltmeter to check for 110 to 120 volts between

(a) the relay terminal that the black wire from the compressor connects to and (b) the capacitor terminal with the 2 white wires & blue wire connected. If voltage is present, go to step 3. If no voltage, the low pressure control or relay are open or there is a loose connection in the compressor circuit. Test each component for continuity; see the appropriate section if a defect is suspected.

3.Turn the power switch OFF and unplug the unit, then disconnect the red and yellow wires from compressor terminals R & S. Using an ohmmeter, check continuity between the points listed below.

4.Compressor terminals C and S: No continuity indicates an open start winding; the compressor must be replaced. Normal start winding resistance 3 to 7 ohms.

5.Compressor terminals C and R: No continuity indicates an open run winding; the compressor must be replaced. Normal run winding resistance is .5 to 2 ohms.

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 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 will provide greater starting torque. If this does not work, the compressor has an internal mechanical defect and must be replaced.

4.6B 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 or allow it to contact your eyes or skin.

3.Remove the burned out compressor. Use rubber gloves if there is any possibility of coming in contact with 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.

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