FRIEDRICH QUIETMASTER KL25J30 (01) PDF Document

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

Before testing, disconnect electrical power to the unit.

Remove the compressor terminal box cover and disconnect wires from the terminals. Using an ohmmeter, check continuity across the following:

1. Terminal “C” and “S” – no continuity means an open winding, and you must replace the compressor.

2. Terminal “C” and “R” – no continuity means an open winding, and you must replace the compressor.

3. Terminal “R” and “S” – no continuity means an open winding, and you must replace the compressor.

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. This condition can be checked as follows:

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 or heating performance test.”

If the test shows:

A. Below normal high side pressure.

B. Above normal low side pressure.

C. Low temperature difference across the coil.

Then the compressor valves are faulty and the compressor must be replaced.

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

2. Using an ohmmeter, test continuity between terminals C-S and C-R. If not continuous, the compressor overload is open and the compressor must be replaced.

Heat generated within the compressor shell is usually due to:

1. High amperage.

2. Low refrigerant charge.

3. Frequent recycling.

4. Dirty condenser.

1. Remove the overload.

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

3. Apply ohmmeter probes to terminals on the overload wires. There should be continuity through the overload.

1. Determine that the capacitor is serviceable.

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

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

4. Apply “live” test cord probes on the red wire and 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.

1. Remove capacitor from the unit.

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

3. For dual rated, 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, then gradually move 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.

NOTE: A shorted capacitor will indicate a low resistance and the pointer will move to the “0” end of the scale and remain there as long as the probes are connected. An open capacitor will show no movement of the pointer when placed across the terminals of the capacitor.

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

1. “Off” Position – no continuity between terminals.

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

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

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

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

Remove wires from the thermostat. Turn the thermostat to its coldest position. Check to see if there is continuity between the two terminals. Turn the thermostat to its warmest position. Check continuity to see if thermostat contacts open. NOTE: Temperature must be within the listed range (60°F ± 2° to 92°F ± 4°) to check the thermostat.

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.

Disconnect 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 or repairing refrigerant leaks (e.g., compressor, condenser, evaporator, capillary tube, refrigerant leaks).

1. Recover the refrigerant from the system at the process tube located on the high side of the system. Install a line tap on the process tube and apply gauges. Recover CFCs in the system to at least 5%.

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

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

4. Drift dry nitrogen through the system and unsolder the more distant connection first (e.g., filter drier, high side process tube).

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

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

7. Leak test the complete system with an electric 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 (do not use regular hoses).

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 will not enter the high side, allow the remainder to enter the low side in small increments while operating the unit.

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

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 equivalent to remove all contamination from the system. Inspect suction and discharge lines for carbon deposits. Remove and clean if necessary.

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

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

Basically, troubleshooting and servicing rotary compressors is the same as on a reciprocating compressor with only a few exceptions:

1. Because of the spinning motion of the rotary, the mounts are critical. If vibration is present, check the mounts carefully.

2. The electrical terminals on the rotary are in a different order than 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, as exact as possible to the nameplate charge.

2. The correct method for charging the 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, gas only, into the low side. The introduction of liquid into the low side, without the use of 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:

Possible Cause: Low voltage.
To Correct: Check for voltage at the compressor. 115 volt and 230 volt units will operate at 10% voltage variance.

Possible Cause: Thermostat not set cold enough or inoperative.
To Correct: Set the thermostat to the coldest position. Test the thermostat and replace if inoperative.

Possible Cause: Compressor hums but cuts off on overload.
To Correct: Hard start the compressor. Direct test the compressor. If the compressor starts, add starting components.

Possible Cause: Open or shorted compressor windings.
To Correct: Check for continuity and resistance.

Possible Cause: Open overload.
To Correct: Test the overload protector and replace if inoperative.

Possible Cause: Open capacitor.
To Correct: Test the capacitor and replace if inoperative.

Possible Cause: Inoperative system switch.
To Correct: Test for continuity in all positions. Replace if inoperative.

Possible Cause: Broken, loose or incorrect wiring.
To Correct: Refer to the appropriate wiring diagram to check wiring.

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

Possible Cause: Inoperative system switch.
To Correct: Test the switch and replace if inoperative.

Possible Cause: Broken, loose or incorrect wiring.
To Correct: Refer to the applicable wiring diagram.

Possible Cause: Open capacitor.
To Correct: Test the capacitor and replace if inoperative.

Possible Cause: Fan speed switch open.
To Correct: Test the switch and replace if inoperative.

Possible Cause: Inoperative fan motor.
To Correct: Test the fan motor and replace if inoperative (be sure internal overload has had time to reset).

If the unit does not cool well, check the following possible causes and corrections:

Possible Cause: Undersized unit.
To Correct: Refer to Sizing Charts.

Possible Cause: Thermostat open or inoperative.
To Correct: Set to the coldest position. Test the thermostat and replace if necessary.

Possible Cause: Dirty filter.
To Correct: Clean as recommended in the Owner’s Manual.

Possible Cause: Dirty or plugged condenser or evaporator coil.
To Correct: Use steam or detergents to clean.

Possible Cause: Poor air circulation in the area being cooled.
To Correct: Adjust discharge air louvers. Use high fan speed.

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

Possible Cause: Low capacity – undercharge.
To Correct: Clean for leaks and make repairs.

Possible Cause: Compressor not pumping properly.
To Correct: Check amperage draw against the nameplate. If not conclusive, make a pressure test.

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

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

Possible Cause: Power cord not plugged in.
To Correct: Plug in the power cord.

Possible Cause: System switch in “Off” position.
To Correct: Set the switch correctly.

Possible Cause: Inoperative system switch.
To Correct: Test for continuity in each switch position.

Possible Cause: Loose or disconnected wiring at the switch or other components.
To Correct: Check wiring and connections. Reconnect per the wiring diagram.

If the evaporator coil freezes, check the following possible causes and corrections:

Possible Cause: Dirty filter.
To Correct: Clean as recommended in the Owner’s Manual.

Possible Cause: Restricted air flow.
To Correct: Check for a dirty or obstructed coil; clean as required.

Possible Cause: Inoperative thermostat.
To Correct: Test for a shorted thermostat or stuck contacts.

Possible Cause: Short of refrigerant.
To Correct: De-ice the coil and check for a leak.

Possible Cause: Inoperative fan motor.
To Correct: Test the fan motor and replace if inoperative.

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

If the compressor runs continually, check the following possible causes and corrections:

Possible Cause: Excessive heat load.
To Correct: The unit may be undersized. Test the cooling performance of the unit. Replace it with a larger unit if necessary.

Possible Cause: Restriction in line.
To Correct: Check for a partially iced coil. Check the temperature split across the coil.

Possible Cause: Refrigerant leak.
To Correct: Check for oil at silver-soldered connections. Check for a partially iced coil. Check the split across the coil. Check for low running amperage.

Possible Cause: Thermostat contacts stuck.
To Correct: Check the operation of the thermostat. Replace if contacts remain closed.

Possible Cause: Thermostat incorrectly wired.
To Correct: Refer to the appropriate wiring diagram.

If the thermostat fails to turn the unit off, check the following possible causes and corrections:

Possible Cause: Thermostat contacts stuck.
To Correct: Replace the thermostat.

Possible Cause: Thermostat set at the coldest point.
To Correct: Turn to a higher temperature setting to see if the unit cycles off.

Possible Cause: Incorrect wiring.
To Correct: Refer to the appropriate wiring diagram.

Possible Cause: Unit undersized for the area to be cooled.
To Correct: Refer to the Sizing Chart.

If the compressor short cycles on overload, check the following possible causes and corrections:

Possible Cause: Overload inoperative. Opens too soon.
To Correct: Check the operation of the unit. Replace the overload if system operation is satisfactory.

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

Possible Cause: Low or fluctuating voltage.
To Correct: Check the voltage with the unit operating. Check for other appliances on the circuit. The air conditioner should be on a separate circuit for proper voltage and be fused separately.

Possible Cause: Incorrect wiring.
To Correct: Refer to the appropriate wiring diagram.

Possible Cause: Shorted or incorrect capacitor.
To Correct: Check by substituting a known good capacitor of the correct rating.

Possible Cause: Restricted or low air flow through the condenser coil.
To Correct: Check for proper fan speed or a blocked condenser.

Possible Cause: Compressor running abnormally hot.
To Correct: Check for a kinked discharge line or restricted condenser. Check amperage.

If the thermostat fails to turn the unit on, check the following possible causes and corrections:

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

Possible Cause: Loose or broken parts in the thermostat.
To Correct: Check as above.

Possible Cause: Incorrect wiring.
To Correct: Refer to the appropriate wiring diagram.

For noisy operation, check the following possible causes and corrections:

Possible Cause: Poorly installed unit.
To Correct: Refer to Installation Instructions for proper installation.

Possible Cause: Fan blade striking chassis.
To Correct: Reposition – adjust the motor mount.

Possible Cause: Compressor vibrating.
To Correct: Check that compressor grommets have not deteriorated.

Possible Cause: Improperly mounted or loose cabinet parts.
To Correct: Check that compressor mounting parts are not missing.

If water leaks into the room, check the following possible causes and corrections:

Possible Cause: Evaporator drain pan overflowing.
To Correct: Clean the obstructed drain trough.

Possible Cause: Condensation forming on the base pan.
To Correct: The evaporator drain pan is broken or cracked. Reseal or replace.

Possible Cause: Poor installation resulting in rain entering the room.
To Correct: Check installation instructions. Reseal as required.

Possible Cause: Condensation on discharge grilles.
To Correct: The evaporator coil is dirty – clean it. This may also be caused by a very high humidity level.

If the thermostat short cycles, check the following possible causes and corrections:

Possible Cause: Thermostat differential too narrow.
To Correct: Replace the thermostat.

Possible Cause: Plenum gasket not sealing, allowing discharge air to short cycle the thermostat.
To Correct: Check the gasket, reposition or replace.

Possible Cause: Restricted coil or dirty filter.
To Correct: Clean and advise the customer of periodic cleaning of the filter.

Possible Cause: Thermostat bulb touching the thermostat bulb support bracket (applicable models).
To Correct: Adjust the bulb bracket.

If you experience prolonged off cycles, check the following possible causes and corrections:

Possible Cause: Anticipator (resistor) wire disconnected at the thermostat or system switch.
To Correct: Refer to the appropriate wiring diagram.

Possible Cause: Anticipator (resistor) shorted or open (applicable models).
To Correct: Replace the thermostat block and resistor.

Possible Cause: Partial loss of charge in the thermostat bulb causing a wide differential.
To Correct: Replace the thermostat.

If there are water leaks outside, check the following possible causes and corrections:

Possible Cause: Evaporator drain pan cracked or obstructed.
To Correct: Repair, clean or replace as required.

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

Possible Cause: Obstructed condenser coil.
To Correct: Steam clean.

Possible Cause: Fan blade and slinger ring improperly positioned.
To Correct: Adjust the fan blade 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 base pan.

For high indoor humidity, consider the following causes and corrections:

Possible Cause: Insufficient air circulation in the air-conditioned area.
To Correct: Adjust louvers for the best possible air circulation.

Possible Cause: Oversized unit.
To Correct: Operate in “Fan-Auto (Moneysaver)” position.

Possible Cause: Inadequate vapor barrier in building structure, particularly floors.
To Correct: Advise the customer.