FRIEDRICH QUIETMASTER KS10J10 (01) PDF Document

* Rating Conditions: 80°F. Room Air Temperature and 50% Relative Humidity with 95°F. Outside Air Temperature at 40% Relative Humidity.

To perform a compressor winding test, first disconnect the electrical power to the unit. Then, remove the compressor terminal box cover and disconnect the wires from the terminals. Using an ohmmeter, check the continuity across the following terminals:

1. Terminal “C” and “S”: If there is no continuity, the winding is open, and the compressor needs to be replaced.

2. Terminal “C” and “R”: If there is no continuity, the winding is open, and the compressor needs to be replaced.

3. Terminal “R” and “S”: If there is no continuity, the winding is open, and the compressor needs to be replaced.

To perform a ground test on the compressor, first disconnect the electrical power to the unit. Use an ohmmeter set on its highest scale. Touch one lead to the compressor body (ensure a clean point of contact for a good connection) and the other probe in turn to each compressor terminal. If a reading is obtained, the compressor is grounded and must be replaced.

Compressor inefficiency is normally due to broken or damaged suction and/or discharge valves. To check for this condition, follow these steps:

1. Install a piercing valve on the suction and discharge or liquid process tube.

2. Attach gauges to the high and low sides of the system.

3. Start the system and run a cooling performance test.

If the test shows below normal high side pressure, above normal low side pressure, and a low temperature difference across the coil, the compressor valves are faulty and the compressor should be replaced.

To test an external type thermal overload on the compressor, follow these steps after disconnecting power to the unit:

1. Remove the overload.

2. Allow time for the overload to reset before attempting to test.

3. Apply ohmmeter probes to the terminals on the overload wires. There should be continuity through the overload. If there is no continuity, it needs to be replaced.

To check the internal overload, which is embedded in the motor windings, follow these steps:

1. With no power to the unit, remove the leads from the compressor terminals.

2. Using an ohmmeter, test for continuity between terminals C-S and C-R. If there is no continuity, the compressor overload is open, and the compressor must be replaced. Note that the overload will automatically reset but may require several hours for the heat to dissipate.

To test the fan motor, follow these steps after ensuring power is disconnected:

1. Determine that the capacitor is serviceable.

2. Disconnect the fan motor wires from the fan speed switch or system switch.

3. Apply “live” test cord probes on the black wire and the common terminal of the capacitor. The motor should run at high speed.

4. Apply “live” test cord probes on the red wire and the common terminal of the capacitor. The motor should run at low speed.

5. Apply “live” test cord probes on each of the remaining wires from the speed switch or system switch to test intermediate speeds.

To test the run capacitor, follow these steps:

1. Remove the capacitor from the unit.

2. Check for visual damage such as bulges, cracks, or leaks.

3. For a dual-rated capacitor, apply an ohmmeter lead to the common (C) terminal and the other probe to the compressor (HERM) terminal. A satisfactory capacitor will cause a deflection on the pointer, which then gradually moves back to infinity.

4. Reverse the leads of the probe and momentarily touch the capacitor terminals. The deflection of the pointer should be two times that of the first check if the capacitor is good.

5. Repeat steps 3 and 4 to check the fan motor capacitor portion.

NOTE: A shorted capacitor will indicate a low resistance, with the pointer moving to “0” and staying there. An open capacitor will show no pointer movement.

Disconnect the leads from the control switch. There must be continuity between terminals as follows:

1. “Off” Position: No continuity between terminals.

2. “Lo Cool” Position: Continuity between terminals “L1” and “C”, “LO” and “MS”.

3. “Med Cool” Position: Continuity between terminals “L1” and “C”, “M” and “MS”.

4. “Hi Cool” Position: Continuity between terminals “L1” and “C”, “H” and “MS”.

5. “Fan Only” Position: Continuity between terminals “L1” and “2”.

To test the thermostat, remove the wires from it. Turn the thermostat to its coldest position and check for continuity between the two terminals. Then, turn the thermostat to its warmest position and check for continuity again to see if the thermostat contacts open. NOTE: The ambient temperature must be within the thermostat’s operational range (60°F to 92°F) to perform this test accurately.

No attempt should be made to adjust the thermostat. Due to the sensitivity of the internal mechanism and the sophisticated equipment required to check the calibration, it is suggested that the thermostat be replaced rather than calibrated.

To test the MoneySaver® switch, disconnect the leads from the switch. Depress the switch to the function being tested:

1. When YES is depressed, there should be continuity between terminals “1” and “2”.

2. When NO is depressed, there should be continuity between terminals “2” and “3”.

The following procedure applies when replacing components in the sealed refrigeration circuit (e.g., compressor, condenser, evaporator) or repairing refrigerant leaks. This should be performed by a qualified technician with the proper equipment.

1. Recover the refrigerant from the system at the high-side process tube using an EPA-approved recovery system.

2. Cut the process tube below the pinch-off on the suction side of the compressor.

3. Connect a line from a nitrogen tank to the suction process tube.

4. Drift dry nitrogen through the system and unsolder the most distant connection first (e.g., filter drier).

5. Replace the inoperative component and always install a new filter drier. Drift dry nitrogen through the system while making these connections.

6. Pressurize the system to 30 PSIG with proper refrigerant and boost the pressure to 150 PSIG with dry nitrogen.

7. Leak test the complete system with an electronic halogen leak detector, correcting any leaks found.

8. Reduce the system to zero gauge pressure.

9. Connect a vacuum pump to the high and low side of the system with deep vacuum hoses or copper tubing.

10. Evacuate the system to a maximum absolute holding pressure of 200 microns or less.

11. Break the vacuum by charging the system from the high side with the correct amount of specified refrigerant. This will prevent boiling the oil out of the crankcase. If the entire charge won’t enter the high side, allow the remainder to enter the low side in small increments while the unit is operating.

12. Restart the unit several times after allowing pressures to stabilize. Pinch off the process tubes, cut and solder the ends. Remove the pinch-off tool and leak check the process tube ends.

In the case of a motor compressor burnout, follow this special procedure:

1. Recover all refrigerant and oil from the system.

2. Remove the compressor, capillary tube, and filter drier from the system.

3. Flush the evaporator, condenser, and all connecting tubing with dry nitrogen or an equivalent to remove all contamination. Inspect the suction and discharge lines for carbon deposits and clean them if necessary.

4. Reassemble the system, including a new drier strainer and capillary tube.

5. Proceed with processing as outlined under hermetic component replacement.

Troubleshooting and servicing rotary compressors is mostly the same as for reciprocating compressors, with a few exceptions:

1. The mounts are critical due to the spinning motion of the rotary compressor. If vibration is present, check the mounts carefully.

2. The electrical terminals on the rotary compressor are in a different order than on reciprocating compressors. The terminal markings are on the cover gasket. Use your wiring diagram to ensure correct connections.

1. The refrigerant charge is extremely critical. Measure the charge carefully, making it as exact as possible to the nameplate charge.

2. The correct method for charging a rotary compressor is to introduce liquid refrigerant into the high side of the system with the unit off. Then start the compressor and enter the balance of the charge, as gas only, into the low side. Introducing liquid into the low side without a capillary tube will cause damage to the discharge valve of the rotary compressor.

If the compressor does not run, check the following possible causes and corrections:

• Low voltage: Check for voltage at the compressor. 115 volt units will operate at 10% voltage variance.

• Thermostat not set cold enough or inoperative: Set the thermostat to the coldest position. Test the thermostat and replace if inoperative.

• Compressor hums but cuts off on overload: This indicates a hard-starting compressor. Direct test the compressor. If it starts, add starting components.

• Open or shorted compressor windings: Check for continuity and resistance.

• Open overload: Test the overload protector and replace if inoperative.

• Open capacitor: Test the capacitor and replace if inoperative.

• Inoperative system switch: Test for continuity in all positions. Replace if inoperative.

• Broken, loose or incorrect wiring: Refer to the appropriate wiring diagram to check wiring.

If the fan motor does not run, check the following:

• Inoperative system switch: Test the switch and replace if inoperative.

• Broken, loose or incorrect wiring: Refer to the applicable wiring diagram.

• Open capacitor: Test the capacitor and replace if inoperative.

• Fan speed switch open: Test the switch and replace if inoperative.

• Inoperative fan motor: Test the fan motor and replace if inoperative. Be sure the internal overload has had time to reset.

If your unit is not cooling well, consider these causes and solutions:

• Undersized unit: Refer to Sizing Charts.

• Thermostat open or inoperative: Set to the coldest position. Test the thermostat and replace if necessary.

• Dirty filter: Clean as recommended in the Owner’s Manual.

• Dirty or plugged condenser or evaporator coil: Use steam or detergents to clean.

• Poor air circulation in the area being cooled: Adjust the discharge air louvers. Use a high fan speed.

• Fresh air or exhaust air door open on applicable models: Close the doors. Instruct the customer on the use of this feature.

• Low capacity due to undercharge: Check for a leak and make the repair.

• Compressor not pumping properly: Check the amperage draw against the nameplate. If not conclusive, perform a pressure test.

If the unit will not run, investigate these possible issues:

• Fuse blown or circuit tripped: Replace the fuse or reset the breaker. If it repeats, check the fuse or breaker size and check for shorts in the unit wiring and components.

• Power cord not plugged in: Plug in the power cord.

• System switch in “Off” position: Set the switch correctly.

• Inoperative system switch: Test for continuity in each switch position.

• Loose or disconnected wiring at the switch or other components: Check wiring and connections. Reconnect per the wiring diagram.

An evaporator coil freezing up can be caused by several factors:

• Dirty filter: Clean as recommended in the Owner’s Manual.

• Restricted air flow: Check for a dirty or obstructed coil and clean as required.

• Inoperative thermostat: Test for a shorted thermostat or stuck contacts.

• Short of refrigerant: De-ice the coil and check for a leak.

• Inoperative fan motor: Test the fan motor and replace if inoperative.

• Partially restricted capillary: De-ice the coil. Check the temperature differential across the coil. Touch test the coil return bends for the same temperature. Test for low running current.

If the compressor runs continuously, here are the potential causes and remedies:

• Excessive heat load: The unit may be undersized. Test the cooling performance of the unit. Replace with a larger unit if necessary.

• Restriction in line: Check for a partially iced coil. Check the temperature split across the coil.

• Refrigerant leak: Check for oil at silver soldered connections. Check for a partially iced coil. Check the split across the coil. Check for low running amperage.

• Thermostat contacts stuck: Check the operation of the thermostat. Replace it if contacts remain closed.

• Thermostat incorrectly wired: Refer to the appropriate wiring diagram.

If the thermostat fails to turn the unit off, consider the following:

• Thermostat contacts stuck: Replace the thermostat.

• Thermostat set at the coldest point: Turn to a higher temperature setting to see if the unit cycles off.

• Incorrect wiring: Refer to the appropriate wiring diagram.

• Unit undersized for the area to be cooled: Refer to the Sizing Chart.

If the compressor cycles on overload, check these possible causes:

• Overload inoperative (opens too soon): Check the operation of the unit. Replace the overload if system operation is satisfactory.

• Compressor attempts to start before system pressures are equalized: Allow a minimum of two (2) minutes for pressures to equalize before attempting to restart. Instruct the customer about this waiting period.

• Low or fluctuating voltage: Check voltage with the unit operating. Check for other appliances on the circuit. The air conditioner should be on a separate circuit with proper voltage and fuse.

• Incorrect wiring: Refer to the appropriate wiring diagram.

• Shorted or incorrect capacitor: Check by substituting a known good capacitor of the correct rating.

• Restricted or low air flow through the condenser coil: Check for proper fan speed or a blocked condenser.

• Compressor running abnormally hot: Check for a kinked discharge line or restricted condenser. Check amperage.

If the thermostat does not turn the unit on, consider the following:

• Loss of charge in thermostat bulb: Place a jumper across the thermostat terminals to check if the unit operates. If the unit operates, replace the thermostat.

• Loose or broken parts in thermostat: Check as described above.

• Incorrect wiring: Refer to the appropriate wiring diagram.

For noisy operation, check these potential issues:

• Poorly installed unit: Refer to Installation Instructions for proper installation.

• Fan blade striking chassis: Reposition or adjust the motor mount.

• Compressor vibrating: Check that compressor grommets have not deteriorated.

• Improperly mounted or loose cabinet parts: Check that compressor mounting parts are not missing.

If water is leaking into the room, investigate the following:

• Evaporator drain pan overflowing: Clean the obstructed drain trough.

• Condensation forming on the base pan: The evaporator drain pan may be broken or cracked. Reseal or replace.

• Poor installation resulting in rain entering the room: Check the installation instructions. Reseal as required.

• Condensation on discharge grilles: This may be caused by a dirty evaporator coil or very high humidity levels. Clean the coil.

Short cycling of the thermostat can be due to:

• Thermostat differential too narrow: Replace the thermostat.

• Plenum gasket not sealing: This allows discharge air to short cycle the thermostat. Check the gasket, and reposition or replace it.

• Restricted coil or dirty filter: Clean and advise the customer of periodic cleaning of the filter.

• Thermostat bulb touching thermostat bulb support bracket: Adjust the bulb bracket (on applicable models).

Prolonged off cycles can be caused by:

• Anticipator (resistor) wire disconnected at the thermostat or system switch: Refer to the appropriate wiring diagram.

• Anticipator (resistor) shorted or open (on applicable models): Replace the thermostat block and resistor.

• Partial loss of charge in the thermostat bulb causing a wide differential: Replace the thermostat.

If the unit is switching from cooling to heating, the cause could be:

• Thermostat sticking: Change the room thermostat.

• Incorrect wiring: Refer to the appropriate wiring diagram.

If water is leaking outside, check the following:

• Evaporator drain pan cracked or obstructed: Repair, clean, or replace as required.

• Water in the compressor area: Detach the shroud from the pan and coil. Clean and remove the old sealer. Reseal, reinstall, and check.

• Obstructed condenser coil: Steam clean.

• Fan blade and slinger ring improperly positioned: Adjust the fan blade to be 3/16″ to 1/4″ from the condenser shroud. Adjust the fan motor mount to allow 3/16″ to 1/4″ clearance between the condenser fan blade and the base pan.

If you are experiencing high indoor humidity, consider these points:

• Insufficient air circulation in the air-conditioned area: Adjust the louvers for the best possible air circulation.

• Oversized unit: Operate the unit in the “Fan-Auto (Moneysaver)” position.

• Inadequate vapor barrier in the building structure, particularly floors: This may require professional advice for the customer.