Air handling unit (AHU) monthly inspection checklist

Controller — No active alarm on the unit controller or building management system

Supply air — Supply air temperature within the set range

Fans — Supply and extract fans run without abnormal noise or vibration

Filters — Filter pressure drop on the gauge

• Below the change mark (Conforming)
• Close to the change mark — plan replacement
• Above the change mark (Non-conforming)

Filters — Filters seated in their frames, no air bypassing them

Coils — Heating and cooling coil fins clean and undamaged

Condensate tray — Drain tray clean and draining freely, no standing water

Condensate drain — Flush the condensate drain line and check the trap is filled

Belts — Fan belt condition and tension

• Good, correctly tensioned (Conforming)
• Worn, cracked or glazed (Non-conforming)
• Loose or misaligned (Non-conforming)
• Direct drive — no belt

Guards — Guards in place over belts, pulleys and couplings

Bearings — No bearing noise and no grease leaking from the bearings

Motor — Motor not abnormally hot, no burning smell

Dampers — Fresh air and return dampers move freely with their actuators

Casing — Access doors close and seal, no air leak at the gaskets

Interior — Any water, mould or wet insulation inside the unit?

Remarks — Observations for the next service