Environmental Test Chambers:
Start-Up and Preventive Maintenance

Preventive Maintenance: How often?

Twice per year, or more frequent if your chamber is heavily used.

Here is a comprehensive start-up and preventive-maintenance checklist:

Electrical System

• main disconnect: check for tight connections and corrosion
• phasing: current and voltage should not be lagging or leading each other
• line and control voltage: connections and terminations
• contact points, timer settings, fuses, and grounding
• general condition of boxes, labels
• compressor head fans and crankcase heaters
• heater frames and elements

  Verify Resistance (Ohms) per Specifications

• compressor three-phase and single-phase elements
• heaters and steam generator elements

Verify Current (Amps) per Specifications

• high-stage, low-stage, and trim compressors
• heaters, circulators, steam generator, condenser fan motor, and blower motor

Instrumentation

• readings correct?
• check configuration, temperature
• limit switches (such as on main door)
• sensors (various, including humidity, RTD, etc.)
• chart recorder -- print quality, mechanical operation

Refrigeration

• low- and high-stage refrigerant charge
• low- and high-stage pressure switch settings
• low- and high-stage oil level
• capacity controls
• low- and high-stage frost
• low- and high-stage discharge temperature
• fan-cycling operation
• condenser and evaporator coils
• inlet and outlet water temperature
• inlet and outlet water pressure
• water regulator
• leak check
• solenoids
• cap tubes
• oil separators
• labels
• valves
• condition of foam insulation
• compressor oils: acid test

Humidity

• humidity sensor (calibration test)
• boiler and boiler hose condition
• water level in wick tank
• boiler leak check
• tightness of fittings
• thermostat
• demineralization cartridge
• atomizer fittings
• condition of nozzles
• pressure regulator: water and air
• dry air purge
• misc. leaks
• solenoids
• desiccant tower transfer
• moisture indicator
• air drier
• pulleys, wheels and belts

General Items

• physical condition of chamber, including insulation
• condition of mineralacs, tie straps
• labels (worn, faded or otherwise illegible)
• panels and knobs (smooth operation?)
• drip pan (in place, corrosion?)
• door and door latch (smooth operation?)
• interior light bulbs
• bearings -- need greasing?
• belts
• fan blades and blower wheels
• gauges (various analog and digital): check for water inside; zero-condition check; calibrate as necessary