Air Handling Unit Maintenance

Before we tell you how to perform air handling unit maintenance, lets cover the basics. It is important to understand what an air handling unit is and their key components before diving into how you can maintain them.

WHAT IS AN AIR HANDLING UNIT?

An Air Handling Unit (AHU), or an air handler, is a piece of equipment that is part of a larger overall HVAC system. These units are commonly found on rooftops, however variations of the unit may be found in utility rooms. Their sole purpose is to regulate air quality, temperature and humidity and then circulate that air in the system. AHU's generally use ductwork to push the air they produce throughout the facility.

WHAT ARE THE MAIN COMPONENTS OF AN AIR HANDLING UNIT?

– Blowers: commonly referred to as fans, are the heart of the AHU system. These are most commonly centrifugal fan and are what provide enough pressure for the air to be moved throughout the system. When these components fail is it commonly a bad relay, run capacitor, blower wheel or the blower motor itself.

– Heating or cooling element: This is most commonly a heating coil or a cooling coil. Depending on the thermostat setting the air is run over a coil before entering the ducting system.

– Filters Racks: These hold a bank of filters that help to remove particles from the air. The type, size and number of filter will vary depending on the unit. Depending on air quality these may need to be changed semi-annual, quarterly or possibly even more frequently.

– Humidifiers: To avoid discomfort caused by drier air in the colder months, a humidifier is used. This increases the humidity of the air as it goes through the system.

– Dampers: these control the amount of air going through the unit. Dampers can be manual or modulating depending on the design.

– Belt: These are commonly found near the fan motor and are changed as they begin to wear inside the unit.

– Heat Exchanger: These are commonly fitted to an AHU for energy efficiency. They allow for exiting conditioned air to increase or decrease the temperature of the incoming outside air. By recovering the residual heat in the exhausted gas, the fresh air introduced into the system is preheated.

YOUR AIR HANDLING UNIT MAINTENANCE CHECKLIST

Routine AHU cleaning and maintenance not only extends the life of equipment but reduces operating costs, downtime costs and troubleshooting costs. It helps mitigate the majority of these expenses because the issues are caught ahead of time.

Use the maintenance checklist below to ensure you don't miss a step:

ㆍExamine electrical disconnect

ㆍExamine control panel and boxes

ㆍCheck contactors/starters

ㆍTighten electrical

ㆍExamine control set points

ㆍLog amp readings

ㆍExamine return air dampers

ㆍInspect outside air dampers

ㆍExamine relief air dampers (if applicable)

ㆍInspect face & bypass dampers

ㆍExamine filter section

ㆍChange filters

ㆍExamine heating coil

ㆍClean heating coil

ㆍExamine drain line & pan

ㆍExamine cooling coil

ㆍClean cooling coil

ㆍExamine drain line & pan

ㆍClean drain line & pan

ㆍExamine supply air fan

ㆍClean supply fan and housing

ㆍLubricate fan bearings

ㆍCheck belts and sheaves on supply fan

ㆍExamine supply fan motor

ㆍLubricate supply fan motor bearings

ㆍExamine return air fan (if applicable)

ㆍClean return fan and housing

ㆍLubricate fan bearings on return fan

ㆍCheck belts and sheaves on return fan

ㆍExamine return air fan motor (if applicable)

ㆍLubricate return fan motor

ㆍExamine exhaust air fan (if applicable)

ㆍClean exhaust fan and housing

ㆍLubricate exhaust fan bearings

ㆍCheck belts and sheaves on exhaust fan

ㆍExamine exhaust air fan motor (if applicable)

ㆍLubricate exhaust fan motor

ㆍCheck fan(s) rotation

ㆍRecord and Check operating amps

ㆍCheck temperature split across coil

ㆍCheck expansion valve

ㆍExamine heating section (if applicable)

ㆍChange Thermostat Batteries

ㆍExamine heater safeties

ㆍExamine other accessories (if applicable)

As always, follow the manufacture recommendations and do not perform maintenance tasks you are not experienced with or trained on.

PREVENT A BREAKDOWN BY CARRYING THESE PARTS

Below is a list of parts you can keep in stock to limit further expenses!

ㆍAir filters

ㆍBelts

ㆍCapacitors

ㆍCoil Condenser Cleaners

ㆍContactors

ㆍFuses

For larger facilities, it can be cost-effective to build your inventory of more expensive replacement parts. Especially if you have five or more pieces of equipment sharing parts like:

ㆍMotor

ㆍCapacitors

ㆍGas Valves

ㆍControl Boards

ㆍCompressors

ㆍBearings

ㆍShafts

ㆍImpellers, etc.

We are an air handling unit (ahu) frame profile & parts supplier. Please feel free to contact us if you need them!