MVHR Location Issue

[worldwidewebs]

I've made an error and I'm looking for advice on the best way to resolve please

 

I was originally going to sit the MVHR on the concrete floor of the plant room with some sort of rubber isolation feet but decided that I could well use the space under the units so mounted it on the wall using the supplied bracket. I've now connected and taped everything up and switched it on - it works!

 

The problem is that there is a faint low frequency hum audible in the adjoining room. This is something I should have thought about - it's a real error of judgement on my part as the wall is only a stud partition (with extra OSB and insulation) but I'm now not sure what to do. Do I rip out all the connections I've made, clean them up and site it on the floor as per the original plan or do I make some sort of platform (wood, steel, bricks!) that would just lift the unit up from the support and away from the wall?

 

I'm short on time and patience at the moment so I'd rather go for the least effort approach in that respect but I also don't want to go through all that effort and find the platform creates its own issues. I feel a little bit swamped with everything I have to do at the moment  

[Bitpipe]

Stack it up on some bricks just now, decouple from wall and see what effect that has before you do anything more radical.

[PeterW]

Got any photos of the unit ..?? Or of the installation ..?

[oranjeboom]

I may have been to careful with my UFH manifold on my block wall, but what I did was the followimg:

 

• stick 10mm of EPS insulation sheet on wall
• place OSB onto EPS sheet
• mechanical fix with screws and rawlplug through the board and EPS into wall with rubber washers separating steel manifold from OSB

 

I don't expect any / much noise from the manifold/pumpset, but thought I may as well try and minimise the risk. Probably overkill in my case and not even sure that my approach would work as UFH is not even running at this stage! But what you may find is placing a few rubber washers between your bracketry and the wall may eliminate the noise/hum somewhat. And potentially no need to take the whole lot down if you can reach each fixing point one at a time?

[ragg987]

This is 90% caused by the vibration transmission caused by tight coupling of the unit to the partition - mechanical transmission from the motors to the wall.

 

We have the same effect, I mounted the bracket on the thickest MDF sheet I could get and insulated the partition, but noise still gets through to the toilet on the other side - we can live with it.

 

There are 2 primary mechanisms to suppress this, decoupling it and reducing it.

 

Decouple can be e.g. rubber washers on the wall bracket (but this is not as easy as it sounds, you need to make sure every side of the mounting screw is not in direct contact with the wall and bracket.) Or maybe create a strong shelf and stand the MVHR on it using vibration dampers - e.g. feet or mats. But you are still hampered by the stud wall being too light.

 

Reducing it is probably best done with weight - concrete or brick wall - not really practical for you. What is your floor? If solid e.g. beam and block or slab then that could be an option.

 

So if you have a solid floor, try the bricks idea that @Bitpipe suggests to prove the concept them perhaps build a table-like support to stand it on, and decouple at the top of the stand (e.g. a vibration mat) and below the stand. Avoid mounting on the partition completely.

[worldwidewebs]

5 minutes ago, ragg987 said:

What is your floor?

The floor is a concrete slab

[ragg987]

1 hour ago, worldwidewebs said:

I'm short on time and patience at the moment so I'd rather go for the least effort approach in that respect but I also don't want to go through all that effort and find the platform creates its own issues. I feel a little bit swamped with everything I have to do at the moment  

Been there and this was exactly the reason I did not pursue the detailing of our MVHR mounting other than to increase the weight of the stud wall with MDF, but I was a bit more relaxed as it is a toilet on the other side.