Bryant R-22 service manual Refrigeration System, Refrigerant, Compressor Oil

Ground Circuit

To determine if a wire has broken or come in direct contact with shell, causing a direct short to ground, follow these steps:

1.Allow crankcase heaters to remain on for several hours before checking motor to ensure windings are not saturated with refrigerant.

2.Using an ohmmeter on R X 10,000 ohm scale or megohmmeter (follow manufacturer’s instructions).

3.Be sure all power is off.

4.Discharge all capacitors.

5.Remove wires from terminals C, S, and R.

6.Place one meter probe on ground or on compressor shell. Make a good metal-to-metal contact. Place other probe on terminals C, S, and R in sequence.

7.Note meter scale.

8.If reading of 0 or low resistance is obtained, motor is grounded. Replace compressor.

Compressor resistance to ground should not be less than 1000 ohms per volt of operating voltage.

Example:

230 volts X 1000 ohms/volt = 230,000 ohms minimum.

Short Circuit

To determine if any wires within windings have broken through their insulation and made contact with other wires, thereby shorting all or part of the winding(s), be sure the following conditions are met.

1.Correct motor winding resistances must be known before testing, either from previous readings or from manufacturer’s specifications.

2.Temperature of windings must be as specified, usually about 70_F.

3.Resistance measuring instrument must have an accuracy within ± 5-10 percent. This requires an accurate ohmmeter such as a Wheatstone bridge or null balance-type instrument.

4.Motor must be dry or free from direct contact with liquid refrigerant.

Make This Critical Test

(Not advisable unless above conditions are met)

1.Be sure all power is off.

2.Discharge all capacitors.

3.Remove wires from terminals C, S, and R.

4.Place instrument probes together and determine probe and lead wire resistance.

5.Check resistance readings from C-R, C-S, and R-S.

6.Subtract instrument probe and lead resistance from each reading.

If any reading is within ±20 percent of known resistance, motor is probably normal. Usually a considerable difference in reading is noted if a turn-to-turn short is present.

REFRIGERATION SYSTEM

Refrigerant

!WARNING

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could result in personal injury or equipment damage.

Puronr refrigerant which has higher pressures than R-22 and other refrigerants. No other refrigerant may be used in this system. Gauge set, hoses, and recovery system must be designed to handle Puronr. If you are unsure consult the equipment manufacturer.

In an air conditioning and heat pump system, refrigerant transfers heat from one replace to another. The condenser is the outdoor coil in the cooling mode and the evaporator is the indoor coil.

In a heat pump, the condenser is the indoor coil in the heating mode and the evaporator is the outdoor coil.

In the typical air conditioning mode, compressed hot gas leaves the compressor and enters the condensing coil. As gas passes through the condenser coil, it rejects heat and condenses into liquid. The liquid leaves condensing unit through liquid line and enters metering device at evaporator coil. As it passes through metering device, it becomes a gas-liquid mixture. As it passes through indoor coil, it absorbs heat and the refrigerant moves to the compressor and is again compressed to hot gas, and cycle repeats.

Compressor Oil

!CAUTION

UNIT DAMAGE HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

The compressor in a Puronr system uses a polyol ester (POE) oil. This oil is extremely hygroscopic, meaning it absorbs water readily. POE oils can absorb 15 times as much water as other oils designed for HCFC and CFC refrigerants. Take all necessary precautions to avoid exposure of the oil to the atmosphere. (See Table 4.)

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