Maintaining Your Air Handling Unit: Essential Servicing Guide

Posted: 31st July 2025

If you’ve invested in an Air Handling Unit (AHU), it’s probably because you care about air quality, energy efficiency, and keeping your building running smoothly. But like any hardworking piece of kit, an AHU needs a bit of TLC to keep it performing at its best. It’s easy to forget it’s there — quietly ticking away behind the scenes — until something goes wrong.

Regular servicing can save you money, extend the unit’s life, and help avoid breakdowns when you least expect them. Whether you’re running a hospital, school, office, or factory, knowing how and when to service your AHU is key.

In this air handling unit servicing guide, we’ll explore why maintenance matters, what a comprehensive service includes, and how to create an effective servicing schedule that suits your site.

Looking for a trusted partner to keep your system in peak condition? At ECE UK Ltd, we custom-build and expertly maintain AHUs across a range of industries — and we know them inside out.

At ECE UK Ltd, we don’t just build Air Handling Units — we build long-term solutions that prioritise performance, reliability, and the health of your indoor environment.

Maintaining Your Air Handling Unit - Essential Servicing Guide

Why Air Handling Unit Servicing And Maintenance Matter

If your AHU isn’t maintained regularly, your entire ventilation system can suffer. That means:

Poor indoor air quality
Increased energy consumption
Unreliable heating and cooling
Risk of microbial contamination
Early system failure

In critical environments such as healthcare, life sciences, or food processing, system failure can also lead to regulatory non-compliance, which is something no facility manager wants to deal with.

Regular AHU routine maintenance helps you stay compliant, comfortable, and energy-efficient. It also supports your sustainability goals and reduces your carbon footprint, especially if you’re working toward Net Zero Carbon Footprint.

Air Handling Unit Servicing And
Maintenance Checklist

Here’s what a comprehensive AHU service typically involves. This isn’t just a once-over — it’s a top-to-bottom inspection and tune-up that covers:

1. Filters

Replace dirty panel, bag, or HEPA filters with clean new filters
Reduces pressure drop, improving airflow and lowering fan energy use
Prevents filter collapse and blow-through
Stops pollutants from circulating through the system

2. Coils & Heat Recovery Systems

Clean heating and cooling coils
Inspect plate heat exchangers, thermal wheels, and run-around coils
Check for corrosion, leakage, and thermal performance
Pay special attention to 3-way mix systems and pool-specific AHUs

3. Fan And Motor Assemblies

Inspect fan bearings, impellers, and belts for wear or damage
Check for dust, debris, or grease build-up
Ensure proper alignment, tension, and secure mounting
Listen for abnormal noise and check for overheating
Lubricate components if required

4. Controls And Sensors

Verify calibration of temperature, RH, CO₂, VOC sensors and setpoints
Inspect control panels for cleanliness, water ingress, and overheating
Check for loose/disconnected wires, fault codes, or diagnostics
Test fan response to speed commands and damper modulation
Confirm schedule accuracy and intelligent control updates
Test safety interlocks for proper function

ECE UK’s air handler maintenance procedures include diagnostics using advanced tools, which are ideal for troubleshooting tricky faults before they become major issues.

5. Condensate System

Flush and disinfect drain trays; swab surfaces for microbial growth
Inspect and verify trap design, sizing, and insulation
Add trap heaters if needed to prevent freezing
Ensure no blockages and proper drainage from all coil sections
Confirm independent or correctly cascaded drain setup

6. Casing, Ductwork & Insulation

Inspect panels, seals, door handles, latches, and hinges for integrity and tightness
Check for missing or damaged fixings, corrosion, or insulation damage
Look for signs of vermin, mould, or leaks
Perform air tightness test in accordance with BS EN 1886

When done correctly, this AHU servicing checklist not only improves airflow but also boosts HVAC system efficiency, saving you money in the long term.

Maintaining Your Air Handling Unit - Essential Servicing Guide

How Often Should You Service Your Air Handling Unit?

There’s no one-size-fits-all answer — it depends on your unit’s configuration, usage, and the environment in which it operates. But as a general rule:

Basic inspection and filter checks: Every 3 to 6 months
Deep cleaning and full functional check: At least twice per year
Component replacements (e.g., belts, actuators): As needed or during annual review

Ask yourself:

Is your building located in an urban or industrial area?
Are you operating in healthcare, manufacturing, or another regulated industry?
Is the unit exposed to high moisture (e.g., swimming pools) or chemicals?

If you’ve answered yes to any of these, your AHU maintenance importance level just went up a notch — and your servicing schedule should reflect that.

When To Schedule Annual AHU Inspection

Ideally, you should align your HVAC unit servicing schedule with seasonal changes, especially before winter and summer peaks.

Spring: Pre-cooling season check
Autumn: Pre-heating season prep
After any major retrofit or refurbishment

Additionally, don’t forget that an annual inspection is the minimum requirement. If you operate in a sensitive or high-use environment (hospitals, labs, food production), servicing may be needed quarterly or monthly.

Maintaining Your Air Handling Unit - Essential Servicing Guide

Speak To The Experts At ECE UK Ltd For Servicing And Maintenance

When it comes to air handling unit services and maintenance, ECE UK goes beyond the basics. Contact our specialist air handling unit servicing team. We are trained not only to manage our custom-built systems but also to maintain and upgrade a wide range of third-party models with precision and care.

Here’s what sets us apart from our suppliers:

Condition reports and compliance testing
Factory Acceptance Testing (FAT) before commissioning
AHU refurbishment, including upgrades to EC fans, new coils, and intelligent energy controls
Parts and spares are available directly from our AAH UK-based stock
Comprehensive technical support, documentation, and guidance from our in-house Support Centre

Whether you need one-off ventilation system maintenance or a tailored long-term service contract, we’ll work around your operations to keep downtime minimal and ensure your environment remains healthy, efficient, and compliant.

Because at the end of the day, AHU servicing isn’t just about the unit — it’s about the quality of the air your people breathe. By following a structured air handling unit servicing guide, you’re investing in:

Healthier indoor air for your occupants
Longer life and reliability from your equipment
Improved HVAC system efficiency
Cleaner, greener, and more sustainable building operations

Call us on 01634 729 690 or email us at sales@eceuk.com and let us keep your AHU running like clockwork — because clean, efficient air doesn’t happen by accident.

Contact our team today

Get straight through to one of our engineers and start discussing the needs of your new air handling unit. Our team are on hand to work out a custom solution for you and your project. Just call 01634 729 690 or send us an email at sales@eceuk.com to get started.

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Maintaining Your Air Handling Unit: Essential Servicing Guide

Why Air Handling Unit Servicing And Maintenance Matter