Ryan4Healthy Home Movement

@Nickfromwales i am not 100% sure if my comment was misinterpreted. what I was trying to say that it considered best practice/common with public health engineers to not combine the WHB and WC branch before going to vertical stack (this is why 99% example show it done this way), Please find attached a quick sketch. I appreciate that the non-common way may work for your installation and others (more than one way to skin a cat). thanks Ryan Epson_29062017073828.pdf

Hi sorry, was interested to see what the actual SFP was of the system..... to compare it with what the manufacture. with regards to: your system resistance is not all the resistance added up, its only the index run. The dampers are used for balance this resistance which should only have minor effect on the index run [the valve furthest from the MVHR unit.] (if balanced 100% correctly you don't need a restrictor on your index). If you have throttled back your index run a lot that means you will have much more resistance than you need. The three biggest resistances are: noise attenuators (manufactured ones), external louvres and discharge terminal. which are all around 10- 30Pa each. Where as duct work is about 1 pa/m if sized correctly .... ryan

What is going to be connected to the end of the drain? Was it your WHB? if so you should have a separate branch going to your stack and not connected to you WC.

is there any way you can measure the power consumption? it would be interesting to know what the resultant (Specific Fan Power) SFP is after the silencers have been fitted. Ryan

Hi Stone, @ProDave has a good point, you will need to maintain your unit and it must comply with CDM regulations. Is this the best solution your designer/installer came up with? If you do not maintain it, your home will become unhealthy. ryan

Hi Stones, Sorry for the bit of a delay, my back ground is I am a chartered building services engineer, so design heating, vent, cooling etc in homes and commercial buildings. What i am not 100% sure is what are you trying to do. are you trying to reduce room noise? building a box around the MVHR tends to deal with the break out noise but what deals with room site is inline duct attenuators. Ryan

Hi, do you have the product literature sheet for the MVHR (attached is an example), from which you can get an idea of what noise levels the unit is meant to produce (the supply db is the key one this is what get transmitted down to the rooms), we typically convert this into an NR level with the aim to get near 30NR (your ears hear things differently at different bands NR method takes this into account). Once you have this, you can understand better what silencer you need or if you system is working correctly. ie if your unit is making too much noise compared to the data sheets you might have too much resistance (fans working to hard) or something else wrong. ryan mvhr_-_lo-carbon_sentinel_kinetic_plus.pdf