Common Failures:
Refrigerant Leaks:
- Symptoms: Starved evaporator coil.
- Detection: Oil residue around mechanical joints and fittings indicates leakage.
- Tools: Electronic or ultrasonic leak detectors locate the general area; soap bubble solution pinpoints the exact location.
- Systems: Automated leak detection systems can alert to leaks immediately after they occur.
Condenser Coil Issues:
- Symptoms: Dirt, debris, and grease on the coil surface cause increased condensing pressure (head pressure) and a rise in conditioned space temperature.
- Maintenance: Coils should be routinely cleaned with a soft brush, compressed air, or liquid coil cleaner. Caution is needed with aluminum fins to avoid damage.
Defrost System Failures:
- Components: Defrost heater, defrost timer or circuit board, defrost thermostat.
- Symptoms: Frost buildup on the evaporator coil, impeding airflow and causing temperature rise in the conditioned space.
- Issues: Heater may not operate or operate with lower wattage; defrost cycles may run too long, consuming more energy; faulty defrost termination switch may prevent proper operation of the evaporator fan motor.
Automatic Pump Down Solenoid Failures:
- Symptoms: Valve may remain closed, causing the compressor to start but cycle on low pressure. Rapid cycling during pump down indicates a leaking solenoid due to improper valve seating.
Importance of Preventive Maintenance:
- Impact: Prevents issues that can lead to significant financial losses, product spoilage, and customer dissatisfaction.
- Routine Inspections: Essential to detect problems before they escalate.
- Case Example: A California supermarket chain was fined over $2.5 million in 2013 for failing to audit and calibrate automatic leak detection equipment, as required by California's refrigerant management program.
- Cybersecurity Concerns: Technicians should advise users to change default usernames and passwords for internet-connected equipment to prevent unauthorized access to settings and alarms.
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