A red or flashing light on your MVHR usually means a fault that needs attention. Here’s what the common warning signs mean and when to call an engineer.
★★★★★ 5-star rated on Google
THE SHORT ANSWER
On most MVHR units, a red or flashing light means the unit has detected a fault, most often a failed fan or circuit board. Some units also use a light to remind you the filters are due.
Every manufacturer uses its lights and codes differently, so check your unit’s manual for the exact meaning. If the light stays on after you’ve checked the filters, the unit needs an engineer.
What we usually find behind each symptom.
A failed fan or circuit board, or a filter reminder on some units.
A few safe checks before you call anyone.
£80
Full diagnosis, duct and airflow checks, PCB testing, written repair quote.
£149
Deep clean, new filters, airflow tested and rebalanced in every room, photo report. 90–120 min.
What customers say after a Ventfix visit.
It’s best not to leave it for long. A unit in fault mode usually isn’t ventilating properly, which lets moisture, condensation and mould build up.
Some units have a filter reset once the filters are changed, so check your manual. If a fault light comes back, the cause needs fixing.
A fault-finding visit is £80 and includes a written quote. Repairs start from £150 plus parts.
Yes. We work on all makes and models, including Vent-Axia, Nuaire, Zehnder and Titon.
Book a fault-finding visit and get a fixed repair quote.
Fill out the form below, and we will be in touch shortly.
