Kitchen smell transfer via MVHR fresh air vents

[Russdl]

Can you reject it under the sale of goods act as ‘…not being of merchantable quality…’?  

[JohnMo]

I was thinking "not fit for purpose" it's not a ventilation unit as required by building regulations. So therefore not compliant with BR or manufacturer installation instructions.

 

Several reasons as you have detailed before, recirculation of smells, high humidity etc.

[Jolo]

Exactly right @Russdl and @JohnMo!

 

I've gotten a template letter from the government's consumer authority, and I'm going to send it shortly.

 

It gives them two weeks to repair or replace it, and if that doesn't happen then I can terminate the purchase agreement unilaterally and they have to give me the money back.

 

I'd really prefer that it didn't have to come to this, but I don't see any other option as nothing is happening.

[Russdl]

19 minutes ago, Jolo said:

and I'm going to send it shortly.

Hopefully that will be sufficient to concentrate their minds. Good luck. 

[Mike]

6 hours ago, Jolo said:

On 20/11/2025 at 13:43, torre said:

You mentioned a smoke test earlier, has this been done? It sounds the obvious next step.

Not yet!

Why not get some smoke pellets & test it yourself? Take a video of of any problems. And disable your smoke detectors...

[Jolo]

15 hours ago, Mike said:

Why not get some smoke pellets & test it yourself? Take a video of of any problems. And disable your smoke detectors...

 

I might try this, though I'm not sure if it will hurry Brink up at all. I feel like I've dotted every i and crossed every t, and asked here and elsewhere to test my sanity!

[Adsibob]

On 20/11/2025 at 12:28, Jolo said:

we're running the unit at around 0.45ach

This sounds very low to me, but I may well be wrong. If you increase the ventilation to at least 1 ach you will drop the humidity. You might also improve the smell issue.

[Adsibob]

Actually, ignore me. I’ve just checked approved doc F off the Regs, and that only requires 0.3ACH so 0.45 is fine.

 Have you had works done recently (eg poured slab or screed or plasterwork which could still be wet, that would explain the excess humidity?

[Jolo]

Nope nothing like that! I'm very sure that the high humidity is because of a leak inside the MVHR unit, so there's extracted moisture being blown into the house along with the smells.

[Jolo]

Well I said I'd provide updates, but there's nothing much to update other than to say I'm really disappointed with the customer service I've had from Brink.

In early December they sent an installer who swapped out the whole unit with a new one which, to our amazement, behaves in exactly the same way. I know you'll think I'm mad, but there is definitely strong odour transfer between the extract and supply ports. We tested this new unit, again just via the ports on the top (to exclude any internal ducting issues) and the problem is the same. I wonder now if Brink have a design flaw or manufacturing issues with the Flair 200/225.

The technician from Brink who came checked out our ducting and external connections, and said it all looked very neat and well-installed. I also got him to smell-test the old unit, which he did reluctantly (not sure why, it only takes a minute), and he acknowledged the problem. I didn't do another one on the new unit before he left, as it never entered my mind that the replacement unit would have the same issue. I clearly trusted them too much!

So I emailed the supplier and Brink, explaining that this new unit had the same problem, and they wrote back telling me they were going to thoroughly inspect the returned unit, and would get back to me hopefully by the end of December. Well it's now February, and I still haven't heard anything at all. They even seem to ignore the supplier when he emails them (at least, they don't include me if they do reply!).

So I've had to send a legal email to the supplier, cancelling the purchase contract due to defective goods. I didn't want to do this, I'd much rather they fixed the issue but they just don't seem interested. I'm not sure how they'll respond to this, I hope they just take it away and refund the money, I have no trust in Brink any more.

[Mr Punter]

How very odd.  This sounds like a fundamental design issue as the two flows should not meet.  Get a refund and maybe try another brand, like Vent Axia.

[Iceverge]

Very strange indeed but it's not entirely impossible there's a bad batch of seals or heat exchanger a floating around. 

 

It would be easy enough to set up a rig to pressurise one side of the unit and see if it leaks out. I'm thinking a couple of bungs, a Schrader valve and a bicycle pump. 

 

Pressurise the exhaust(or inlet) side and see if it leaks out immediately. Perhaps something as simple as a dab of sealant would be enough to cure it. 

Edited February 2 by Iceverge

[Jolo]

Agreed, it can only be something such as a design issue or manufacturing flaw.

 

Either way, I've sent the legal email cancelling the purchase contract due to defective goods (and it's been acknowledged) so I guess legally it's Brink's unit now, and I'm just waiting for them to collect it!

[ProDave]

Just  footnote to confirm smells should not transfer around the house.

 

I had to paint some stuff with Hammerite recently and it was way too cold to do so in the garage, so I painted them in the utility room and kept the door shut.

 

Stinky stuff Hammerite, but not the slightest whiff of it anywhere else in the house.

[JohnMo]

1 hour ago, Jolo said:

so I guess legally it's Brink's unit now, and I'm just waiting for them to collect it!

So what are you replacing it with?

 

Enthalpy or normal heat exchanger?

[Jolo]

52 minutes ago, JohnMo said:

So what are you replacing it with?

 

Enthalpy or normal heat exchanger?

 

Great question -- and one which I've been pondering a lot, so any input is welcome!

 

The main benefit of the enthalpy exchanger, besides not drying the air out, is that there's no convenient drain point right now, so it felt worth the extra price. While the main house drain passes directly beneath the MVHR cupboard, there are two concrete floors in between them, and that was putting me off it last summer! But adding a condensate drain doesn't feel too difficult now I've discovered those drill-patch-pipe things that just clamp on. 

 

The enthalpy exchanger options I've found are mostly Zehnder, a few units in the confusingly broad ComfoAir range, which are a few hundred euros more expensive than the Brink we have. The Q350 for example. The main down-side of the Q350 is the size, it's got a maximum airflow of 350 m3/h, which is much larger than we need, and so the unit is physically larger, although I think would just about fit in the MVHR cupboard with maybe 15cm space on each side. It's also a lot heavier at 48kg, so I'd be tempted to get an installer to fit it. The upside of that unit is that, as our top airflow is 180 m3/h, and we typically run it around 70 m3/h, we'd always be running it very slowly, which should mean it's super-efficient.

 

For non-enthalpy units, having looked at other brands, Zehnder is of also a popular choice there, and they have options which cost less than the Brink we have now. I also quite like the look of the Duco Energy Comfort units, they've just introduced a 250 m3/h unit which would fit the bill, although I can't find it listed for sale yet. https://www.duco.eu/uk-ie/products/mechanical-ventilation/ventilation-units/ducobox-energy-comfort

[JohnMo]

Titon HRV also sold by Beam under a different badge and lower price point. You can get enthalpy exchangers if you want 

[-rick-]

11 minutes ago, Jolo said:

I also quite like the look of the Duco Energy Comfort units, they've just introduced a 250 m3/h unit which would fit the bill, although I can't find it listed for sale yet. https://www.duco.eu/uk-ie/products/mechanical-ventilation/ventilation-units/ducobox-energy-comfort

 

Looks interesting. Wonder how their multizone stuff works with building regs.

[Jolo]

On 04/02/2026 at 11:50, ProDave said:

Just  footnote to confirm smells should not transfer around the house.

 

I had to paint some stuff with Hammerite recently and it was way too cold to do so in the garage, so I painted them in the utility room and kept the door shut.

 

Stinky stuff Hammerite, but not the slightest whiff of it anywhere else in the house.

 

Somehow I missed your reply when you sent it -- but thanks for this confirmation, Dave! 

 

What you describe is exactly how I expected the system to work, and also how it's marketed -- but our Brink Flair unit doesn't behave this way at all. Any smell in the extraction rooms is immediately blown into the supply rooms.

 

Out of interest, what system do you have, and would you recommend it?

[Jolo]

My faulty Brink Flair unit has now been returned, and I bought and installed a DucoBox Energy Comfort 325. All of the problems I attributed to the Flair have now gone away. This is as good a like-for-like test as you're going to get, everything is the same - same house, same ducting, same vents, only the main unit has changed. 

Just for completeness, I want to mention two additional (objective, measurable) tests I did on the Brink Flair in the last days we had it, using a CO2 and humidity monitor. Why didn't I think of this earlier!!

I placed the monitor inside one of the supply vents, luckily we have two through-wall vents which are perfect for this (https://www.ventilationland.co.uk/en_GB/p/uniflexplus-wall-manifold-rear-connection-1x-o90-mm/9744/) so the whole monitor can sit in the incoming airflow. We then left it for a few minutes so the values could settle down and we could get a general background reading: the RH was about 55% and the CO2 was about 450ppm.

First test was a humidity test: I boiled a kettle in the kitchen and let the steam be sucked into the extract valve. The RH jumped to 70%, then went back down again. I also showered, and again the RH shot up to 70% (see attached graph).

Second test was a CO2 test: I disconnected the flexible noise dampener which is connected to the Flair's extract port, and breathed into it several times. The CO2 reading at the supply vent briefly increased, from about 450 to 485, then went down again. I tried this again with my partner, and the CO2 reading went up to about 540 PPM. (This one is difficult to show on the graph though, as the unit only logs every five minutes, so the brief peak isn't logged. It's difficult to keep breathing into the extract!)

This can only be because there was a leak inside the unit. This does echo the results of my smell test, but is more objective and can't be written off as me having some sort of super-nose!

I consider that to be proof that the Flair was faulty, despite Brink's inistence that it wasn't. 

The new Duco works as expected. I've done the same tests, and showering makes no difference at all to the moisture levels of the incoming air. It's been in for over a week now, and the RH in the house hovers around 44 to 54%. Even while boiling a big pan of potatoes there's no moisture on the kitchen window, whereas with the Flair it would be dripping wet.

With the Brink Flair the humidity in the house was always high. The 55% mentioned above was only acheived because we had left the above-window vents open, and aired the house out every day by opening the windows for several minutes. Until we started doing that it was always above 60% and would jump to over 70% when cooking/showering.

I must say I'm really disappointed with Brink. They showed little interest in the problem, I had to nag them constantly, and were almost totally unresponsive, and it seems they closed my 'case' several times. If I hadn't kept the pressure up they would never have responded. Which is a shame, as I really liked their products otherwise. 

Edited Wednesday at 16:30 by Jolo
Made link into an actual link