Broken MVHR unit advice

Dylan Woods · Mar 16, 2023

Hello all,

I’m looking for some advice regarding a recently broken MVHR unit in my flat, model Heatrae Sadia Advance.

The unit is out of warranty and Baxi, who provide product support, have suggested I employ a Heating & Ventilation engineer to diagnose the problem.

Before I do, I would like to attempt to resolve the issue myself, perhaps with some help from these forums. Where I am up to:

I have recently changed the filters on the unit and given the fan unit a clean.
I performed a reset as per the manual.
I note that my unit doesn’t have an LED indicator on the top (see attached photo) so I am unsure why the malfunction has happened.
When I turn the unit off by mains power, and then turn it back on, the unit makes a vibrating sound for around 10 seconds and then stops.
Baxi have recommended I check for blockages in the ducting or that I may have any issue with the motor assembly or PCB, both may need replacing.

My questions / thoughts from this are:

Does anyone have experience of this issue?
New components are very expensive (upwards of £550) and I have no guarantee that these will fix the problem. It seems a big risk to purchase these blindly. See links below to components.
If the ducting is dirty, would this stop the unit from working altogether? We’ve had the unit for about 5 years.
I found a similar looking MVHR unit (link below) and wondered if this might be a more cost effective replacement than attempting to replace individual components.