vent axia MVHR advice

[David-1712]

Hello, 

 

just looking for some advice on my MVHR. We moved into the house a few months ago and the previous owner had this installed when the house was first built in 2013. Didn’t no much, if anything about them but he gave an overview of how it worked. 
 

I’ve a few questions though regarding how it should be setup in terms of flow rates, it has been set at 45% normal air flow from the day we moved in. The heat recover part - it seams to be cold air coming into the supply rooms from each ceiling vent. I thought it would of be at least a little warm? 

 

there’s an extract in the kitchen, pretty much right above the cooker but don’t feel it does much at all in terms of removing any odours or steam. Same with the bathroom extracts, when the showers on, room still fills up with a lot of condensation. As shower does seem to trigger the humidity sensor and boosts it to 54%
 

How does the summer bypass work on this system? 
 

attached some photos of what is installed and also a diagram of the layout the owner left. On the layout drawing there is sum of L/s for trickle and also for boost. Is that what I should be setting up my normal and boost air flow to be? Convert the Litres/sec to cubic meters and hour than work out the percentage of the max flow rate the unit can provide?

 

any other tips to get the most out of the system? 
 

With moving in and getting settled, some plumbing jobs to take care first, I’ve only just started to look into the MVHR system now. 

 

[Marvin]

Hi @David-1712

 

The flow rates for each inlet and outlet are on the top right hand side of the plan. 

 

The total of these ( picture a bit out of focus) should equal the minimum extraction, and therefore inlet of air related to the square meteridge of the building quicker. 

 

Vent axia have designed this to comply with building regulations.

 

You can run it faster but in cold weather the heat will be removed from the building quicker.

 

The seperate flows are usually confirmed using an Anemometer following the instruction manual. 

 

Also check the filters as shown, also how the summer winter system works.

Edited September 5, 2022 by Marvin
Clarification

[Marvin]

The heat recovery part tries to bring the outside air which is coming in, to meet the temperature of the internal air.

 

If the outside air is colder than the inside air, it will increase the temperature of the incoming air. 

 

If the outside air is warmer than the inside air, it will decrease the temperature of the incoming air. 

 

Summer setting means the temperature of the incoming air is not altered. 

 

Not set to summer ( may be named recovery I can't remember what the switch says) will bring the outside air towards the temperature of the inside air.

 

In the height of summer when over hot outside we use  recovery because then the mvhr brings the outside hot air DOWN towards the more cooler home temperature.

[JohnMo]

I really wouldn't start messing with any settings, as these should all be configured, you cannot just change one thing without messing most other settings.  You need to know what you are doing, with the correct test kit.

 

Things you need to check

Extract ducts, may have a filter at the extract point.  The nozzle just slides out of the ceiling if there is a filter it will be cone shaped. Remove and hoover out 6 monthly replace annually if installed.

 

The main MVHR unit will have filters inside, inspect every 6 months hoover out and replace annually.  Make sure there is no accumulation of water.

 

If you have boost switches use these prior to a shower and during cooking.

 

In trickle mode the extract nozzle will just about hold up two sheets of toilet paper

 

[Adsibob]

If you don't have boost switches, I would recommend installing a couple. Maybe one in the kitchen and one in each toilet.

Also check the spaces underneath each internal door. When the door is closed, you should have 7600mm2 of space between the door and the threshold. If you don't, then airflow will be impeded. For example, a 760mm wide door would need a 10mm gap to give you 7600mm2 of space. Wider doors need proportionately less.

[Dreadnaught]

On the subject of summer bypass, here are the rules for my Brink unit. I think most units work similarly.

 

[Blooda]

Looks like a Sentinel Kinetic plus [but check out the model before ordering filters], same as ours. First thing, as others say, Change the filters, they will be clogged up, you've been in there some months, and if previous owner did not change them, a hoover out will not be sufficient.  Filtermate.co.uk will supply them [other companies are available :)] about £20 per pair. 

 

You tube video here on changing on a similar unit.

 

How to replace the filters on a Vent-Axia MVHR unit - Sentinel Kinetic - YouTube

 

A bit on summer bypass here.

 

Vent Axia Sentinel Kinetic - summer bypass info (greenbuildingforum.co.uk)

 

Might want to sort out a working platform around it as well, something the Builder / Installer should have done,

[Adsibob]

On 06/09/2022 at 20:10, Dreadnaught said:

On the subject of summer bypass, here are the rules for my Brink unit. I think most units work similarly.

 

I have a brink as well, probably the same machine, and never understood the logic of this. E.g. on the first row, isn’t the third bullet rendered redundant by the first one?

[Dreadnaught]

2 hours ago, Adsibob said:

never understood the logic of this. E.g. on the first row, isn’t the third bullet rendered redundant by the first one?

 

Good point. I think the third bullet is a typo. It should refer to "Bypass temperature from dwelling". This is how the setting is referred to in the setting menu. It makes sense then.

 

It being a typo is supported by the conditions in the manual for the Brink Renovent Excellent 400, as follows: