MVHR mouldy and full of water

[haddock]

Not a pretty sight is it? The exchanger is covered in mould on the same side as the condensate drain. 

 

It could be this has something to do with the house having combined MVHR and hot air central heating, which has been discussed a few times on here recently in less than glowing terms. 
 

The bottom right section is where the external air comes in and the bottom is full of water. That side doesn’t have a drain.
 

Bottom left is where the air goes out to the outside. There’s a bit of water and mould there but the drain is working (I just poured 2L down).  But lots of mould on the exchanger in that quadrant. 
 

I hadn’t looked inside for a year or two, when I fixed a problem with the condensate drain freezing up. That’s all fixed now and anyway it hasn’t approached zero this winter yet. 
 

Any pointers please? Just as a sanity check… it seems weird that the bottom two quadrants are external air and the top two are internal air, shouldn’t the air streams cross over in the exchanger? This is a Brink Renovent HR, paired with a Brink Allure gas air heater which blasts air around the house at 800-1,350m3/h even when the heating isn’t on. Obviously looking to get rid of the Allure and switch to some form of heat pump, probably an air to air one separate from the MVHR based on the comments on here. 

 

Thanks for any thoughts especially on the pooling water issue. 

[haddock]

(Apologies, looking through my posting history, I posted something very similar four years ago! At the time @jack mentioned a possible fix which Brink had applied.)

[Iceverge]

Any link to be fix. I had something similar last year with ours (proair 600) but I put it down to a tilt in the unit and not being able to drain properly. 

 

Must have another look again to see if it's ok. 

[RobLe]

Our Vent Axia Sentinel Kinetic had a puddle in it some 6 or 7 years ago.  It was weird - like the drain was blocked with some biological thing.  Anyway, I unclogged it as best I could, and plumbed in the other drain (there are two, front and back) as well.  Haven't had a problem since. 

We also had problems with the drain icing up, as originally I had it dripping outside onto a flat roof - it iced up, blocked, and leaked inside, there must have been over 10litres of water all told into the loft, it made a stain on a bedroom ceiling.  The drain is plumbed into the bath drain now, which doesn't go outside so doesn't cause a problem. 

[MikeGrahamT21]

As others have mentioned, check how the unit is positioned with a spirit level. Some have profiled polystyrene which allows you to mount level, and some don’t meaning you have to mount off level to allow drainage

[Pocster]

1 hour ago, RobLe said:

Our Vent Axia Sentinel Kinetic

Scared to open mine now after 2 yrs of use - no issues .

Guess I should take a peak …

[jack]

2 hours ago, haddock said:

(Apologies, looking through my posting history, I posted something very similar four years ago! At the time @jack mentioned a possible fix which Brink had applied.)

 

Ah yes, sorry. I said I'd take a look and get back to you but I didn't!

 

The fix was to lay a strip of flexible plastic over the top of the polystyrene "hump" that guides the heat exchanger in - something like this:

 

 

You slide the heat exchanger back on over this, and the channel under the heat exchanger holds it in place (this pic is from your previous post about the problem):

 

 

The fix from Brink was similar, although they used very thin aluminium tape that tore badly the first time I took the heat exchanger out to clean it. I used some spare DPM I had lying around and it worked really well.

 

The idea is to have it extend far enough out from the sides that any condensation is directed away from the hump to the drain. Also make it a couple of inches longer than the heat exchanger and bend the ends up so that everything is directed away from the ends.

 

I think doing this avoids water passing over joints in the internal mouldings that wick it away to where it shouldn't. I haven't had any problems since I did this.

 

It's also worth checking your drains are clear and that the unit is level. Also, spray around some dilute bleach after you've cleaned it out.

[haddock]

5 hours ago, jack said:

The idea is to have it extend far enough out from the sides that any condensation is directed away from the hump to the drain. Also make it a couple of inches longer than the heat exchanger and bend the ends up so that everything is directed away from the ends.

This is terrifically helpful, thanks Jack. Was preparing to order a new unit but will get this sorted. 
 

In other news, this afternoon I’ve discovered that my MVHR barely works when the gas air heater fan is on. And that fan has been on for 15 years…

[jack]

Good luck @haddock, fingers crossed it works.