Air Handling Units, Maintained and Refurbished
Installation, maintenance, repair and refurbishment of air handling units for offices, shops, industrial buildings and other larger properties across Sussex, Surrey and Lincolnshire.
What an Air Handling Unit Does
An air handling unit, usually shortened to AHU, is the large cabinet that draws air in, cleans it, heats or cools it, and pushes it through ductwork to the rooms of a building. Where a wall mounted air conditioner treats the air already in one room, an AHU supplies conditioned fresh air to many rooms at once, and often extracts stale air at the same time. They sit on roofs, in plant rooms and in ceiling voids of offices, factories, shops and other larger buildings.
JAC Air Conditioning Ltd installs, maintains, repairs and refurbishes air handling units across Sussex and Surrey from our Horsham office, and across Lincolnshire from our base at Fosdyke. The engineers who fit and service our air conditioning also work on AHUs, so a building with both kinds of plant can be looked after by one company rather than two.
Because an AHU runs for long hours and moves a great deal of air, small faults build up quietly. A filter that is never changed, a belt that has stretched or a damper that has stuck can leave rooms stuffy, noisy or uncomfortable long before anything actually stops. Regular attention keeps the air clean, the airflow balanced and the running costs under control.
Through the AHU, Stage by Stage
Follow the air from the intake to the rooms, and back out again. Each stage does one job, and each one wears in its own way, which is why a service is a list of specific checks.
Keep scrolling to move the air
Outside Air Intake and Damper
What It Does
Fresh air is drawn in through a weather louvre that keeps out rain and leaves. A motorised damper behind it sets how much outside air the unit takes, and closes when the building is empty.
What Servicing It Needs
We check the louvre is clear, the damper blades move freely and close fully, and the actuator answers the controls. A stuck damper is a common reason for a stuffy building.
Air Handling Work We Carry Out
Our air handling work covers the whole life of a unit, from a new installation to keeping an older one running well.
Installation and Upgrades
New AHUs chosen for the airflow the building needs, and upgrades to existing systems that no longer keep up with it.
Filter Replacement
Filters changed on a schedule so the air stays clean and the fan does not work harder than it should.
Coil Cleaning
Heating and cooling coils cleaned so air passes through freely and heat transfers as the unit was designed to.
Fans, Motors and Belts
Fan and motor checks, belt tension and wear, and bearing inspections, which is where many mechanical faults begin.
Dampers and Controls
Dampers checked for free movement and correct position, with the controls tested so the unit responds as it should.
Airflow Testing
Airflow measured and adjusted so each part of the building receives the air it was designed to get.
Inside an Air Handling Unit
Most AHUs are built from the same sections laid out in a line. Outside air enters through an intake, often mixed with a share of air returning from the building, and passes through one or more stages of filters. Many units then pass the air through a heat recovery section, such as a plate exchanger or a thermal wheel, which takes warmth from the stale air leaving the building and gives it to the fresh air coming in.
Next come the coils: a heating coil for winter and a cooling coil for summer, with a drain tray beneath the cooling coil to collect the water that condenses on it. The fan, driven by its motor either through a belt or directly, pushes the treated air into the supply ductwork. Dampers at the inlets and outlets control how much air moves and where it is drawn from.
Each of those parts wears in its own way, which is why AHU maintenance is a list of specific checks rather than a general clean.
Maintenance and Repair of AHUs
A maintenance visit to an air handling unit covers filter replacement, coil cleaning, belt and bearing inspections, motor checks and airflow testing, along with a look at the drain tray, the door seals and the condition of the casing. Filters are the most frequent task, because a blocked filter starves the building of air and makes the fan work harder for less result.
When a fault turns up, we repair it with as little disruption to the building as possible. Common problems include belts that slip or snap, bearings that run noisily, motors that trip, dampers that stick and drain trays that overflow. Where the unit is part of a wider plant, AHU visits can sit inside a planned maintenance contract alongside the air conditioning, so both are covered on the same schedule and reported in the same way.
Refurbishing an AHU Instead of Replacing It
Air handling units are large, heavy and often built into the structure of a plant room or roof. Replacing one can mean cranes, roof work and a long shutdown. In many cases the casing and frame are still sound and the problems lie in the parts inside, which is where refurbishment makes sense.
Refurbishment work includes upgrading damaged panels and insulation, replacing worn fans, motors and dampers, reducing noise levels and reconfiguring airflow settings to suit how the building is used now. An office that has been divided into smaller rooms, or a floor that has changed use, often needs its airflow set again rather than a new machine. We inspect the unit first and tell you honestly whether refurbishment or replacement is the sensible choice.
Air Handling Alongside Your Air Conditioning
In many buildings the AHU supplies fresh air while the air conditioning deals with the heat in each room. The two need to work together. If the AHU delivers air that is too warm, the air conditioning works harder to make up for it, and if the airflow is out of balance, some rooms are always too warm or too cold whatever the thermostat says.
Because JAC works on both, we can look at the whole picture when a building is uncomfortable rather than treating each system on its own. Where new coil connections or plant room pipework are part of the job, our mechanical assembly work covers it, brazed, pressure tested and insulated. For larger buildings, our commercial air conditioning page explains how we design and install the cooling side to suit the air handling plant already in place.
How an Air Handling Job Runs
Maintenance, repair and refurbishment all follow the same five steps.
Survey the Unit
We inspect the AHU, its access, its controls and the rooms it serves, and note its condition.
Agree the Scope
You receive a written description of the work and a written price before anything starts.
Plan the Shutdown
Work that needs the unit switched off is timed around the building, often early in the day or out of hours.
Carry Out the Work
Filters, coils, fans, motors, belts, bearings and dampers are worked on as agreed, with worn parts replaced.
Test and Record
Airflow and operation are checked on restart, and you receive a written record of what was done.
Absolutely thrilled with the air conditioning installation provided by JAC. From start to finish, the entire process was incredibly smooth and efficient, resulting in a system that exceeds all expectations.
The initial consultation was comprehensive, with the team taking the time to understand my specific needs and providing knowledgeable advice on the best system for my space. They were patient, addressing all my queries and concerns with professionalism and expertise.
Air Handling Questions, Answered
What is the difference between an air handling unit and air conditioning?
An air handling unit moves and treats air for a whole building or a large part of it, usually bringing in fresh air from outside, filtering it and heating or cooling it before it travels through ductwork. Air conditioning units such as wall mounted or cassette systems treat the air within individual rooms. Many commercial buildings have both, with the AHU supplying fresh air and the air conditioning handling the heat in each space.
How often should an air handling unit be serviced?
It depends on how hard the unit works and how dirty the incoming air is. Filters usually need the most frequent attention, and a unit beside a busy road or on an industrial estate will load its filters faster than one in a quiet location. After a first visit we recommend a schedule for your unit, which can be built into a planned maintenance contract so each visit is booked ahead.
Can you refurbish an old AHU rather than replace it?
Often, yes. If the casing and frame are sound, we can upgrade damaged panels and insulation, replace worn fans, motors and dampers, reduce noise and reconfigure the airflow to suit how the building is used now. Refurbishment avoids much of the disruption of lifting out a large unit. We inspect first and tell you plainly whether refurbishment or replacement makes more sense for your building.
Why is our air handling unit so noisy?
The usual causes are a belt that has stretched or worn, bearings that are running dry or failing, a fan that has gone out of balance, or loose panels vibrating against the casing. Noise is often the first sign of a mechanical fault, so it is worth having it looked at before the part fails. We can find the cause and, where needed, refurbish the unit so it runs more quietly.
Do you work on air handling units in Lincolnshire?
Yes. JAC Air Conditioning Ltd covers Lincolnshire from our base at Fosdyke near Boston, as well as Sussex and Surrey from our office in Horsham. Air handling installation, maintenance, repair and refurbishment are available in both regions, and buildings in both can come under the same maintenance arrangement with one set of records.
Will the building have to be empty while you work on the AHU?
Rarely. Most maintenance needs only a short shutdown, and we time any work that needs the unit off around the building, which might mean an early start, a quiet afternoon or a weekend. For larger refurbishments we agree a programme with you in advance, so you know when the unit will be off and when fresh air will be back.
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Air Handling Across Sussex and Surrey
From the Horsham office we cover Guildford · Godalming · Horsham · Dorking · Brighton · Worthing · Chichester · Bognor Regis · Haywards Heath · Burgess Hill · Billingshurst · Cranleigh · Hassocks · Storrington, and the villages around them, with Lincolnshire covered from our base at Fosdyke. That includes air handling maintenance and refurbishment in Dorking, Horsham, Brighton, Worthing and the other towns above. See every area we cover.
Arrange an Air Handling Survey
If you manage a building in Sussex, Surrey or Lincolnshire with an air handling unit that is noisy, tired or simply overdue for attention, call JAC Air Conditioning Ltd on 01403 733 492 or use our contact page to arrange a survey. Every quotation is free, comes in writing and carries no obligation.