AHU Maintenance and Servicing

Keeping Air Handling Units Running Smoothly

An air handling unit that’s maintained properly can run for twenty-five years. One that isn’t will cost you more every year it stays in service… in energy, in emergency call-outs, and eventually in replacement.

i-Flow Technologies provides air handling unit maintenance across the Midlands and throughout the UK, delivered by our Electroair division. From planned preventative maintenance contracts to one-off servicing and emergency breakdown response, we keep AHUs running efficiently, compliantly and without unplanned downtime.

Our engineers come from an AHU background rather than a general HVAC one. They survey, repair, refurbish and build these units, which means when something is wrong they usually know why before they open the panel.

Planned Preventative Maintenance

Most AHU failures give warning. Bearings get noisy before they seize, belts glaze before they snap, and coils foul gradually rather than suddenly. Planned maintenance is about finding those things on a scheduled visit rather than on a Monday morning.

A planned programme covers the unit on a regular cycle – typically quarterly, though the right frequency depends on the environment the unit works in and how critical it is. Units in dusty industrial settings, kitchens or coastal locations need attention more often than a unit serving an office.

Each visit is documented, so you have a record of condition over time rather than a series of unconnected call-outs. That record is what tells you whether a unit is holding steady or heading toward replacement, and it’s what makes budgeting predictable.

A Typical AHU Service

Filters

  • Condition, differential pressure and remaining life
  • Replacement to the correct grade and fit
  • Seal and frame integrity — a filter that bypasses is doing nothing
 

Fans and motors

  • Bearing condition, noise and vibration
  • Belt tension, wear and alignment on belt-driven units
  • Motor current draw and running temperature
  • Impeller condition and cleanliness
 

Coils

  • Fin condition and fouling
  • Heating and cooling performance against expected duty
  • Frost protection operation
  • Condensate trays, drains and traps
 

Dampers and Actuators

  • Free movement and correct positioning
  • Actuator operation and linkage condition
  • Frost and fire damper function

 

Heat Recovery

  • Thermal wheel or plate exchanger cleanliness
  • Bypass damper position and operation
  • Recovery performance against design

 

Casing and Access

  • Panel integrity, seals and air leakage
  • Access door catches and hinges
  • Corrosion and insulation condition

 

Controls

  • Set points, run times and sequencing
  • Sensor accuracy
  • Alarm and fault history

 

Hygiene

  • Internal cleanliness against relevant standards
  • Drain traps and standing water
  • Any evidence of microbial growth
 
 
 

Maintenance Contracts

We tailor AHU maintenance contracts to the plant rather than selling a standard package. A single unit serving a small office and a plant room full of critical units need very different arrangements, and the contract should reflect that.

A typical contract sets out:

  • The number of planned visits per year and what each covers
  • Which consumables — filters, belts, drive components — are included
  • Response times for breakdowns, and whether cover extends out of hours
  • Labour rates for anything falling outside the scope
  • Reporting: what you receive after each visit and in what format

 

The point of a contract rather than ad-hoc call-outs is predictability. You know what the year costs, the visits actually happen, and we build up a picture of your plant over time instead of arriving cold each occasion.

We’re equally happy to carry out one-off servicing where a contract isn’t wanted, or where you want to see how we work before committing.

Emergency Breakdown

When an AHU stops, the building notices quickly. Temperatures drift, air quality drops, and in some environments a process or a compliance requirement is compromised within hours.

Our engineers carry diagnostic equipment and commonly needed parts, so a significant proportion of breakdowns are resolved on the first visit rather than becoming a two-stage job with a wait for parts in between.

Where a part does need ordering, our manufacturing capability through EA Air Handlers means we can often fabricate or source components that would otherwise carry long lead times — coil sections, casing panels, access doors. On older units where the original manufacturer no longer supports the product, that’s frequently the difference between a repair and a forced replacement.

Surveys and Condition Assessment

If you’ve inherited a building, taken on a new portfolio, or simply don’t know what condition your plant is in, a survey is the sensible starting point.

Our engineers carry out a detailed on-site inspection covering mechanical and electrical components, fan and motor performance, coil condition, filtration, casing integrity and overall airflow performance. You get a clear picture of what you have, what condition it’s in, and what it’s likely to need.

That report supports the decisions that follow — whether a unit should be maintained as-is, refurbished, upgraded, or replaced. We’ll tell you honestly when maintenance has become a holding action with diminishing returns rather than keep taking the money.

Maintenance and Compliance

Maintenance isn’t only about keeping the unit running. In many buildings it’s also what demonstrates compliance.

SFG20 is the recognised standard for building maintenance schedules, and it defines the tasks and frequencies most facilities teams work to. Our planned maintenance aligns to it. We’ve written more on what SFG20 means for your AHU.

TR19 governs ductwork cleanliness for both hygiene and fire safety. Ductwork is easy to neglect precisely because it isn’t visible — our guide to TR19 ductwork cleaning explains what’s required.

HTM 03-01 applies to healthcare ventilation, where pressure regimes and air quality are clinical requirements rather than comfort ones. See our guide to HTM 03-01 compliance.

Legionella risk exists wherever there’s standing water in an AHU — humidifiers, cooling coils, condensate trays. It’s part of every service visit, and we’ve covered it in Legionella and your air handling unit.

Some Sectors We Maintain

Healthcare

Hospitals, clinics and care settings where ventilation is a clinical requirement and downtime is not an option.

Education

Schools, colleges and universities, with maintenance planned around term dates and holiday shutdowns.

Commercial Offices

Comfort, air quality and energy performance, with work scheduled around occupancy.

Industrial & Manufacturing

Process environments, harsh conditions and units that work harder than commercial equivalents.

Retail & Hospitality

Customer comfort maintained with minimal disruption to trading.

Data Centres

Cooling that cannot be interrupted, where maintenance has to be planned around continuous operation.

We’re AHU specialists, not general HVAC contractors. The business was founded by two directors from AHU manufacturing and AHU installation backgrounds. Air handling is what we do, rather than one line on a longer list.

We manufacture as well as maintain. Through EA Air Handlers we build bespoke units in-house. That means we understand these units at component level, and we can fabricate parts for older plant that others would tell you is beyond repair.

We work in live buildings. A great deal of our work is in facilities that cannot shut down — hospitals, airports, continuous processes. Maintenance that fits around your operation rather than interrupting it.

We’ll tell you when to stop spending. When a unit has reached the point where maintenance is no longer economic, we’ll say so and set out the alternatives rather than keep billing for visits.

Why Choose i-Flow?

Maintenance FAQ

How often should an AHU be serviced?

Quarterly is typical for most commercial units, though the right frequency depends on the environment the unit works in and how critical it is. Units in dusty, greasy or coastal conditions need more frequent attention than one serving an office. A survey will establish the right interval for your plant.

What's included in an AHU maintenance contract?

Planned visits, filter and belt changes, mechanical and electrical checks, performance testing, and a written report after each visit. Breakdown response and out-of-hours cover can be included where needed.

Contracts are tailored to the plant rather than sold as a fixed package, so a single unit serving a small office and a plant room full of critical units are scoped quite differently.

Do you maintain units you didn't install?

Yes. Most of the units we maintain were installed by someone else. We survey the unit first so we know exactly what we're taking on, and you get a clear picture of its condition before any contract starts.

What happens if a unit fails between visits?

Contract customers get priority response. Our engineers carry diagnostic equipment and commonly needed parts, so a significant proportion of breakdowns are resolved on the first visit rather than becoming a two-stage job with a wait for parts in between.

Can you maintain older or obsolete units?

Usually. Because we manufacture air handling units ourselves, we can fabricate components for units the original manufacturer no longer supports — coil sections, casing panels, access doors. That's frequently the difference between a repair and a forced replacement, and it's a common reason older plant gets replaced unnecessarily.

Do you cover the whole UK?

Yes. We're based in the Midlands and carry out maintenance work nationally.

Talk to Us About Your AHU Maintenance

Whether you need a planned maintenance contract, a one-off service, or a survey to establish what condition your plant is in, we’re happy to take a look.

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