DX AND GLYCOL COMPUTER ROOM AC (CRAC) 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 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

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 piping, electrical components, and wiring
• 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 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 recommend out door fan settings is 50 degrees for a single fan system, 50 and 54 degrees for systems with multiple fans and verify glycol freeze point

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 

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 .