MT-AT – Twin-pipe systems

Filter inspection and replacement: check pressure drop across supply and return air filters (EU3/EU4/EU7 class); replace per manufacturer interval or when differential pressure exceeds set limit

Coil inspection: visually inspect heating and cooling coils for fouling, corrosion, and fin damage; flush water-side coils annually and verify no leakage at connections

Fan and motor check: inspect impeller blades for fouling, corrosion, and mechanical damage; verify motor current draw against nameplate, check bearings for noise and vibration

Drain pan and condensate system: clean drain pan and condensate drain line to prevent biological growth (Legionella risk) and blockage; verify trap is functioning correctly

Casing and access panels: inspect double-skinned panels for corrosion, insulation integrity, and seal/gasket condition; verify air-tightness class is maintained (EN 1886 Class A/L1/L2)

Damper operation: check motorized and manual dampers (mixing, shut-off, bypass) for correct stroke, absence of corrosion on blades and linkages, and proper sealing when closed

Humidifier and steam/water distribution: inspect humidifier elements or nozzles for scale and biological fouling; verify steam grid or water spray distribution is uniform

Controls and safety devices: verify temperature sensors, pressure transmitters, safety thermostats, and fire/smoke detection interlocks are calibrated and operational; test unit shutdown sequence