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0 troubleshooting, 1 troubleshooting - refrigeration – Reznor YDSA Operation Manual User Manual

Page 43

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Form O-Y P/N 273647R1, Page 43

IMPORTANT:

Do not release refrigerant to the atmosphere!

If required service procedures include the adding or removing of

refrigerant, the service technician must comply with all federal,

state and local laws. The procedures discussed in this manual

should only be performed by a qualified HVAC technician.

NOTE: Unit is equipped with a phase loss/phase reversal control. If system

does not start, check phase of electrical supply.

See Control Instructions,

Form CP-Y-D19 or Form

CP-Y - D21, for information

on the unit controller.

7.0 Troubleshooting

7.1 Troubleshooting - Refrigeration

General Refrigeration Circuit

SYMPTOM

POSSIBLE CAUSE

REMEDY

A. Compressor

will not start.

1. Power off, loose electrical connections or

fuse open.

1. Check disconnect switch, fuses and wiring. Replace parts or

repair as necessary

2. Compressor contactor not closing.

2. Check voltage to contactor coil, transformer, slave relay, system.

Replace parts as necessary.

3. Internal compressor thermal overload

open.

3. If compressor is hot, allow 2 hours to cool. See D. Below.

4. Compressor defective.

4. Check compressor for electrical failure. Compressor may be

seized; check refrigerant. If necessary, replace compressor.

5. High or low pressure switch open or

defective.

5. If manual reset (high pressure), reset switch. (Switch opens at

600 psi and will not reset above 400 psi.)

If auto reset (low pressure) does not reset and everything else is

OK, replace low pressure switch,

P/N 216380.

B. Compressor

starts but

cuts out on

low pressure

(low pressure

switch

activates at 35

psig.)

1. Low refrigerant charge.

1. Check subcooling; see Paragraph 3.6.

2. Airflow restricted.

2. Check for dirty evaporator coil, dirty filters, dampers closed, iced

evaporator coil, and/or improper belt. Check motor amps. Check

duct design.

3. Restriction in refrigerant line.

3. Check subcooling and superheat (Paragraph 3.6). Check

operation of the thermal expansion valve. Check for pressure drop

across the filter drier.

4. Defective low pressure switch.

4. Check switch (opens 35 psi; closes 50 psi). If defective, replace

low pressure switch,

P/N 216380.

C. Compressor

starts but

cuts out on

high pressure

switch.

1. Refrigerant overcharge.

1. Check subcooling; see Paragraph 3.6.

2. Condenser fan motor defective.

2. Check fan motor.

3. Condenser coil inlet obstructed or dirty.

3. Check coil and inlet clearances and for possible air recirculation.

4. Air or non-condensables in system.

4. Check high side equalized pressure reading with equivalent

outdoor temperature.

5. Defective high pressure switch.

5. Check switch (opens 600 psi; proof 700 psi; manual reset allowed

below 400 psi). If defective, replace high pressure switch,

P/N

216379

.

6. Restriction in discharge or liquid line.

6. Check subcooling and superheat (Paragraph 3.6). Check

operation of thermal expansion valves.

D. Compressor

cuts out

on thermal

overload.

1. Low voltage.

1. Check voltage.

2. Sustained high discharge pressure.

2. Check running amperage and conditions described in I.

3. High suction and discharge pressures.

3. Check thermal expansion valve operation, check for air in system.

4. Defective compressor overload.

4. If compressor is hot, allow compressor to cool for two hours.

Recheck for open circuit.

5. Improper refrigerant charge.

5. Check subcooling (Paragraph 3.6).

6. Bearings or pistons too tight.

6. Check for low oil level.

7. Allow time for compressor to cool.

7. Check dome temperature of the compressor.

E. Noisy

compressor.

1. Reverse rotation.

1. Check at startup. If the suction pressure rises and discharge

pressure drops, shut down the compressor. Switch the 3-phase

wiring connections.

2. Refrigerant overcharge.

2. Check pressures and subcooling (Paragraph 3.6).

3. Liquid flood back.

3. Check thermal expansion valve setting. Check subcooling for

refrigerant overcharge (Paragraph 3.6).

4. Tubing rattle.

4. Dampen tubing vibration by taping or clamping. Carefully bend

tubing away from contact where possible.

5. Compressor defective.

5. Check internal parts. Replace defective parts or compressor.

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