020 3951 5133

MVHR Repair London — Fast Ventilation Fault Diagnosis

Noisy, leaking or completely dead MVHR unit? Collide Group repairs Mechanical Ventilation with Heat Recovery systems across London from a £120 call-out — covering attendance and full fault diagnosis. Same-day and next-day appointments, all major brands including Vent-Axia, Nuaire, Titon and Zehnder.

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Quick answer

MVHR repair in London starts from a £120 call-out, which covers the engineer attending and fully diagnosing the fault. A small repair fee applies only if we complete the repair on that first visit, and any parts are quoted before we order them. Collide Group is a WRAS-certified building services specialist based in Northolt, offering same-day and next-day MVHR repair across all of Greater London.

Common MVHR Faults We Fix

MVHR units run continuously, so wear shows up in predictable places. These are the faults we see most often in London flats.

Noisy or Humming Unit

Worn fan bearings, unbalanced or dirty impellers, blocked filters forcing high fan speeds, or resonating ductwork. A grinding noise usually means a motor is on its way out.

Water Leaking From the Unit

Blocked, frozen or badly fallen condensate drains cause water to back up and leak — often through a ceiling. Common, and urgent before it causes damage.

Unit Not Running At All

Tripped breaker, switched-off isolator, failed PCB, blown transformer or a seized fan motor. We test the supply and the board before condemning anything.

Weak or No Airflow

Blocked filters, a fouled heat exchanger core, crushed or disconnected flexible ducting, or a system that has drifted out of balance since commissioning.

Condensation, Damp & Mould

Almost always a symptom, not a cause — the system is running below its design airflow, or has been switched off. We measure and rebalance to fix it properly.

Control & Sensor Faults

Unresponsive control panels, faulty humidity or CO2 sensors, boost switches that do nothing, and stuck summer bypass dampers causing overheating.

How Our MVHR Repair Works

No guesswork and no surprise invoices. We diagnose properly, tell you exactly what we have found, and agree the cost with you before we carry out any repair.

  • £120 call-out — engineer attends and fully diagnoses the fault
  • Electrical supply, PCB, fan motor and sensor testing
  • Airflow measured against the original design rates
  • Condensate drain, trap and ductwork inspection
  • Findings explained to you, with any repair cost agreed up front
  • Most repairs completed on the first visit from van stock
  • 12-month warranty on parts we supply and labour we carry out

MVHR Brands We Repair

Vent-AxiaNuaireTitonZehnderVaillant recoVAIRSystemairBrinkEnviroVentAirflowDomusBlaubergItho Daalderop

Related work in London: MVHR Service London · HIU Repair London · HIU Service London · Bulk Servicing London · All Services

Don't Just Switch It Off

When an MVHR unit gets noisy or starts playing up, the instinct is to switch it off at the isolator. In a modern airtight flat that is the worst thing you can do — MVHR is usually the only ventilation the property has.

With the system off, moisture from showers, cooking and drying clothes has nowhere to go. Within weeks you typically see streaming windows, damp patches and black mould on cold walls and around window reveals — and a property that no longer meets Building Regulations Part F. Repairing the unit is almost always quicker and cheaper than dealing with the mould afterwards.

MVHR Repair from £120

A £120 call-out covers attendance and full fault diagnosis. A small repair fee applies only if we successfully complete the repair on the first visit, always at fair and competitive rates, with any parts quoted before we order them.

Call 020 3951 5133Request a Quote

MVHR Repair FAQs

How much does MVHR repair cost in London?
MVHR repair in London starts from a £120 call-out, which covers the engineer attending and fully diagnosing the fault. If we can complete the repair on that first visit, a small repair fee applies on top, always charged at fair and competitive rates. Any parts required are quoted before we order them.
Why is my MVHR unit so noisy?
The most common causes are dirty or unbalanced fan impellers, worn fan bearings, blocked filters forcing the fans to run at high speed, loose or resonating ductwork, or debris inside the unit. A humming or grinding noise usually points to a failing fan motor, which should be looked at quickly before it seizes.
Why is my MVHR leaking water?
MVHR units produce condensate as warm, moist air passes through the heat exchanger. If the condensate drain or trap blocks, freezes or was installed with the wrong fall, water backs up and leaks out of the unit — often through a ceiling. This is a common fault and usually a straightforward fix, but it should be dealt with immediately to avoid damage.
Can you repair my MVHR the same day?
In most cases yes. We carry common filters, condensate parts and fan spares, and most faults are resolved on the first visit. If a specialist part such as a manufacturer control board or fan assembly has to be ordered, we make the system safe, quote the part and return as a priority.
My MVHR has stopped completely — what should I check first?
Check the fused spur or isolator switch next to the unit has not been switched off, and check the consumer unit for a tripped breaker. MVHR units are often isolated accidentally during decorating or other works. If power is present and the unit is still dead, the fault is usually the PCB, transformer or a failed fan motor and needs an engineer.
Should I just turn my MVHR off if it is faulty?
No. MVHR is the only ventilation in most modern airtight flats, so switching it off leads to condensation, damp and black mould within weeks, and may breach Building Regulations Part F. If your unit is faulty, get it repaired rather than turning it off.
Which MVHR brands do you repair?
All major brands including Vent-Axia, Nuaire, Titon, Zehnder, Vaillant recoVAIR, Systemair, Brink, EnviroVent, Airflow, Domus, Blauberg and Itho Daalderop.

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MVHR Problem? Call London's Specialists

Same-day and next-day MVHR repair across Greater London. Speak to a specialist ventilation engineer today.

Call 020 3951 5133Book a Repair