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 --

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