Air handler - DOAS (Dedicated Outside Air System)

Filter inspection and differential pressure measurement (pre-filters and fine filters); replacement per manufacturer interval or when dP exceeds set threshold

Cooling and heating coil condition: check for fouling, corrosion, fin damage, and refrigerant or water-side leaks; clean as required

Fan assembly and drive: vibration measurement, bearing lubrication, belt tension and wear check (belt-driven units), motor insulation resistance test

Condensate drain pan and drain line: clear blockages, check for biological growth (Legionella risk), verify correct slope and unobstructed flow

Damper blades and actuators: verify full travel, check blade sealing surfaces for corrosion or warping, test actuator response and end-stop limits

Casing integrity: inspect panels for corrosion (especially in marine salt-air environment), door/access panel gasket condition, insulation continuity

Controls and instrumentation: calibrate temperature and humidity sensors, verify control valve and actuator function, check setpoint accuracy and alarm operation

Heat recovery device (if fitted, e.g. energy recovery wheel or plate exchanger): fouling inspection, leakage test between supply and exhaust airstreams, drive belt/motor check