Air handling unit refurbishment

Air handling units are the real work-horses of air conditioning systems, mixing the return and outside airflows before providing filtered, heated or cooled air to the supply air ducting network. In a commercial environment they typically operate 70 hours per week but in a hospital situation the air handling unit might never stop - except for maintenance.

Typically an air handling unit consists of a mixing plenum, pre and secondary filters, heating and cooling coils and a supply air fan which is often belt-driven. They are normally fabricated from sheet steel, internally insulated with a faced, fibreglass lining. They can be the size of a 2-seater couch or a 3-bedroom house.

Often in the life of the unit there are periods of limited or non-existent maintenance that rapidly leads to the deterioration of some or all of the components in varying degrees.

• The interior of the unit becomes increasingly dirty over time - often because of sloppy filter maintenance and dirty outside air.
• The steelwork is particularly susceptible to corrosion due to the high moisture content of the air leaving the cooling coil during summer conditions.
• The eroding effects of the airflow can delaminate the internal linings over time so that they shed fibres into the supply airstream - impacting on the air quality of the spaces served.
• The filter frames corrode and enable air to bypass the filters.
• The coils trap dust and dirt between the fins which has escaped the filters and thus reduces the the heat transfer efficiency of the coils. Bacterial growth can form on these surfaces.
• The fan(s) and drive system become dirty from dust and dirt which bypasses filters and the shedding from drive belt wear. A dirty fan impeller reduces the efficiency of the unit and often delivers less airflow.

The deterioration of the unit reaches a point where it must either be replaced or repaired. Often it is impractical to replace the unit due to access limitations or the cost of doing so is prohibitive. This is where Clean Air Management can help by refurbishing the componentry of the unit in-situ and thus extending the life of the air handling unit for maybe another ten years, often at a fraction of the cost of a new unit.

Clean Air Management has the skills to carry out the following remedial work to air handling units:

• Remove all the internal linings for replacement with new fibre-free cleanable linings.
• Remove corrosion, passivate and prime paint the metal surfaces.
• If the corrosion is too extensive for treatment then individual panels can be replaced with new.
• Clean and sanitise all internal surfaces and componentry.
• Clean and sanitise heating and cooling coils.
• Repair and replacement of filter frames and servicing of filters.
• Replacement of fans, drives and motors.
• Up-rating of the filters and fans to provide improved airflow and filtration.