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?
A basic diagram of an AHU. Set-ups vary from unit to unit. Photo courtesy of Bill Kosik
– 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:
Examine electrical disconnect
Examine control panel and boxes
Check contactors/starters
Tighten electrical
Examine control set points
Log amp readings
Examine return air dampers
Inspect outside air dampers
Examine relief air dampers (if applicable)
Inspect face & bypass dampers
Examine filter section
Change filters
Examine heating coil
Clean heating coil
Examine drain line & pan
Examine cooling coil
Clean cooling coil
Examine drain line & pan
Clean drain line & pan
Examine supply air fan
Clean supply fan and housing
Lubricate fan bearings
Check belts and sheaves on supply fan
Examine supply fan motor
Lubricate supply fan motor bearings
Examine return air fan (if applicable)
Clean return fan and housing
Lubricate fan bearings on return fan
Check belts and sheaves on return fan
Examine return air fan motor (if applicable)
Lubricate return fan motor
Examine exhaust air fan (if applicable)
Clean exhaust fan and housing
Lubricate exhaust fan bearings
Check belts and sheaves on exhaust fan
Examine exhaust air fan motor (if applicable)
Lubricate exhaust fan motor
Check fan(s) rotation
Record and Check operating amps
Check temperature split across coil
Check expansion valve
Examine heating section (if applicable)
Change Thermostat Batteries
Examine heater safeties
Examine 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!
Air filters
Belts
Capacitors
Coil Condenser Cleaners
Contactors
Fuses
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:
Motor
Capacitors
Gas Valves
Control Boards
Compressors
Bearings
Shafts
Impellers, etc.
Want Help With Your Air Handler Maintenance?
Talk to the maintenance Pro’s! One of our HVAC technicians can identify problems quickly and keep your system operating at peak efficiency. Allow an expert to check refrigerant levels, make adjustments to the blower, examine electrical connections and perform an overall wellness check on your system. This ensures your entire system is in good working condition can prevent breakdowns from occurring. Give us a call at 1-800-237-3141 or email sales@rasmech.com. Our team is here to help!
Heat pumps are an essential component of many commercial HVAC systems, helping to regulate temperatures and maintain comfortable working conditions year-round. However, like any mechanical…
Heat pumps are an energy-efficient alternative for heating and cooling commercial buildings. A water source heat pump (WSHP) uses water as its heat source, instead…
Tube heaters are a type of electric heating element that are used in a variety of industrial and commercial applications. These heaters are provide efficient…