Chilled Water, DX & Glycol HVAC System
Preventive Maintenance – Scope of Work
Minor PM
SYSTEM CONTROLS & MICROPROCESSOR OPERATION
Visual inspection and check:
- Ensure microprocessor and or solid state control system is functioning properly
- Verify the parameters, and adjust to verify the operation of the reheats and mechanical cooling, chilled water and ECONO-COOL operation. If applicable record the components run hours
- Operation of the relays, contactors, and check contacts for pitting and burning
- All electric connections and terminals for tightness with power off (using a voltmeter), and check voltage. All units should be +10% of nameplate
EVAPORATOR
Visual inspection and check:
- Evaporator condition
- For refrigerant leaks
- The drain lines for obstructions and corrosion
- Chilled water control actuator valve
HEAT REJECTION DEVICE: DX CONDENSER / DRY COOLER / INTERNAL GLYCOL CONDENSER
Visual inspection and check:
- For refrigerant leaks / glycol leaks
- Overall condition of the coil, system refrigerant or glycol/chilled water piping, electrical components, and wiring. Verify chilled water temperature
- Verify low ambient control being utilized, and verify the operation maintains proper head pressure during low ambient operation
HUMIDIFIER SYSTEM INFRARED AND STEAM
Visual inspection and check:
- Steam / Infrared humidifier operation; clean either as required
- If automatic water flush system is used to prevent mineral deposits, check timer operation
- Condensate pump operation, clean and flush as required
REHEAT AND DEHUMIDIFICATION
Visual inspection and check:
- General condition of heaters, relays, and contactors
REFRIGERANT – CIRCUIT / COMPRESSOR SECTION
Visual inspection and check:
- System compressors oil level and refrigerant leaks
- Refrigerant sight glass moisture indicator
FAN AND FAN DRIVES
Visual inspection and check:
- Check bearings for noise and excessive wear Blower Motor & Belt condition for tightness, and adjust or replace as needed
- Drives and pulleys for tightness and excessive wear
FILTERS
- Check all filters
Major PM
– Includes all tasks done during Minor PM visit plus the following:
HEAT REJECTION DEVICE: DX CONDENSER / DRY COOLER / INTERNAL GLYCOL CONDENSER
Power wash coils: if possible remove any paper, leaves, and debris within four feet of the condensers
- Tighten electrical connections and record currents of the condenser fan motors and glycol pump
- If the associated units have the ECONO-COOL option, the recommended outdoor fan settings is 50 degrees for a single fan system, 50 and 54 degrees for systems with multiple fans and the glycol freeze point needs to be verified.
REFRIGERANT – CIRCUIT / COMPRESSOR SECTION
- Use Mego-Meter to determine the condition of the compressor windings
- Tighten Electrical connections and Record currents of the compressors
- Use refrigeration gauges to monitor suction and discharge pressure, verify superheat and record
- Check super heat and record
CHILLED WATER SYSTEMS
- Check chilled water supply temperature and Record
- Check the chilled water control actuator valve
- Check / inspect the chilled water coil
HUMIDIFIER SYSTEM INFRARED AND STEAM
- Tighten Electrical connections and Record currents
REHEAT AND DEHUMIDIFICATION
- Tighten Electrical connections and Record currents
FAN AND FAN DRIVES
- Lubricate fan and motor bearings. Install grease fittings if not supplied with unit (if applicable)
- Tighten Electrical connections and Record currents of the motor
- Alignment of Sheave or Pulleys as required
FILTERS
- Replace air filters as required
— Documentation of inspection with recommendations for any corrective action deemed
necessary will be provided on both Minor and Major PMs —