Deniance

Can anyone give me some tips on setting up the testo 405i for comissioning mvhr? I thought I set my unit up correctly and was supplying 20 litres per second into my 4 rooms (5 l/s per room ) had a bit of condensation on the window in one room so tried to make it a few more litres per second in that room to deal with it anyways, i wasn’t getting the 5l/s per room that I did last week so I tried to setup again Except this time I can’t get the figures right i made a 100mm tube like in the pictures but if I use it this way I get a reading, if I flip the tube the other way so the probe is further away I get a different reading also I disconnected one pipe from the mvhr unit and used the testo to set exactly 21 l/s coming out of the mvhr, then I put duct back on and went around expecting to get 5 l/s in each of the 4 rooms except now I’m getting 8 l/s in each room (32 l/s in total)! So this is where I’m getting stuck, measure unit to produce 21 l/s, but then Total of all supply outlets is 32 l/s? is it because it’s windy outside or batteries low?

This was the big bedroom this morning , cold side of the house, still reduced from what it was but meh i followed document F and divided the fresh air equally between the supply rooms so each room is like 5.5 litres per second , can I adjust the valves so the other rooms are less and this double bedroom gets a few more litres per second or am I just wasting my time as the windows are old and house isn’t airtight?

This was on a cold night and we’ve gone from waterfall windows to mist! So mvhr does help with condenstion in an old leaky house!

Added a few pics just to show grilles and condensation free windows!!

Can you explain it to me like your talking to a child😂 all this flow rate stuff pickles me

How do I know if I’ve got the anemometer set correctly? I have the 150mm cone that goes into the 125mm cone that goes into 100 mm duct about 400mm long with the anemometer stuck in the side in a stuffing gland i set the testo to extract or supply and put 100mm as the diameter and I’ve balanced the supply and extract as well as I can, the supplies get divvied up from 21 l/s to 5 l/s to each of the 4 rooms, but the grilles are almost closed , there’s like about 5mm gap in the grille , the testo says there’s 5 litres coming out but it feels like it wouldn’t blow a rizla paper about cindensation has certainly reduced by about 95% in the main bedroom but need a really cold night to prove it more, house doesn’t seem any fresher to me and it just makes me think the unit isn’t on fast enough or I’m measuring the flow wrong?

Just the ticket, sure as hell ain’t paying a tenner for it though! I’ll check Amazon cheers

Any idea what the last collar is made of on the anemometer cone? I’ve got the 100 mm pipe and the bit that takes it to 125, and I’ve got the 125 to 150 collar, but need one more to make it a little bit bigger

I’ve bought two Brookvent, the items seem ok, but they are very very expensive, replacement fans are knocking on for 300 each, sensor failed on mine and that was 50 beans, when it turned up it’s a circuit board and a 5 inch cable , looks about 99p worth, the filters are crap quality, they are stringy foam around a metal square and they start breaking as you remove them, all the green coloured 1.2 air cycles you can’t open them or service them, the aircycle 1.3 you can they are helpful on the phone but won’t help with other stuff , I bought a cheap eBay 1.3 but I rang up and asked to buy the pcb to make it a digital version and they tell you it can’t be done and you have to pay best part of 2 grand for a new unit but you don’t

If a bedroom is 3x5x2.4 metres that’s 36m3 or 36,000 litres if the room is getting filled with air at 5 l/s , 300 litres a minute 18,000 litres an hour then this room will take 2 hours to have all its air replaced with fresh air? is that right? Too much or too little?

I just thought that because my two extracts are very short , bathroom is 1.5m and kitchen is 1 metre and it exits the wall about 300mm above unit that the extract pot would be lower than the supply pot? The supply duct is 4 supplies and the last one has got to be about 20 metres and a few bends and reducers , just assumed the supply would have to work harder to get air to all the distant places but I guess the anemometer doesn’t lie right? It all seems balanced I’ll have another go after work and make sure I’ve got it right when I tried leaving the furthest supply wide open , like grille wound out so it looked silly, and tried to get 21 l/s to flow I just couldn’t get it, even turned the pot up and couldn’t hit 21 l/s, so I closed it down until it looked like a grille again and started getting the figures, so I guess I opened it too much and it couldn’t build any pressure? I’ll post some pictures later

Ok so I’ve finished the install!!! I tried setting it up with the testo hot wire 405 Bluetooth probe in the 100mm duct as others have done set the app to l/s and added the damping to stop measurements jumping about i closed 3 out of 4 supply valves and opened the furthest one all the way, got it to 21 l/s by adjusting the pot, then opened the other 3 valves and fiddled and fiddled until I got all 4 valves at 5 litres per second as best I could then I did both extracts same way to get 21 litres per second, as best I could so when it’s measured they are there or there abouts for a balanced supply and extract but…… 5 litres per second in each room doesn’t seem very strong , can hardly feel it, don’t think it would even blow a candle out! Is that right? also even though they are nearly extracting and supplying the same the supply trickle pot is at a different position to the extract trickle pot supply is say at 10 o’clock position and extract is at 12 o’clock position? but I guess if I’ve measured all the valves and they balance out then the that’s just how it is? is there anything else I need to do? if I meet the rates in normal mode , what should I set boost to? In this unit boost has to be higher than trickle

Think that’s the right way I’ve entered them? 0.97 doesn’t sound very good?

Are these figures ok? Am I measuring in the right place? Poked the probes under the insulation and left them there for an hour, set heating to 22 extracting 22, outisde air in is 15.6 heat recovered air into house is 21.2 is this how you even measure it or do I need the temperatures at the grilled in the rooms?

If you share some pictures using the add files buttons we can take a look and see what Sami issues you are having, get some zoomed out pictures of outisde the property showing drains on the floor that the drainpipes connect to etc

There’s a dry trap for the big condensate, but nothing has condensed yet , I’ve been checking, the smaller condensate takes whatever runs back down the extract , i angled to run inside rather than drip outside , this drips down and I’m using the trap right at the bottom to stop any smells , this is always kept full of water from the washing machine and it’s also in the extract pipe so any smells will go outside anyways , I hope

why are the extraction rates higher for a kitchen than a bathroom? I was playing about yesterday trying to get the extracts right, and I assumed the bathroom would of had the highest extraction rates not the kitchen? my bathroom is the steamiest room of all i did however manage to get nearly dead on 13 l/s and 8 l/s for the two extracts and it was barely above speed one , and the unit is barely moving! think it was 30 decibels stood in front of machine So I didn’t even need to boost the machine to meet rates, but what should you set the boost at to clear a shower or toilet smell? Or are the rates in the table already taken that into account?

That’s great thanks, everytime I’ve read about setup it’s always people using the ones with little fans on the top and cutting certain size cones etc, are these ones more sensitive to lower air flows? also all this setup on the unit and all the figures used to supply and extract rooms, are they just for the unit running at normal speed and boost is just an extra function? If that makes sense?

Originally it was going to be loft mount but then changing filters would do my head in and the in and out would be close to chimneys and smoke, and the condensate was an issue as I knew the upstairs bathroom was getting moved downstairs, so yeah I didn’t have motivation to complete it, but new extension out the back made us gain a utility room between new extension and the house , it made sense for the in and out through the wall, makes sense for condensate, made sense for filter changes, just made the ductwork about a million times harder getting it up to the loft but hey Ho I’m sure I’ll get there in the end! All ducts were taped up when left and the unit had protective caps on it

Right I’ll get on with the install asap see if I can finally finish it off , thanks fir all the help , I’ll reply to this thread no doubt when I’m trying to set it up!

I’ve just googled the testo you mentioned , how does that work? I though you had to use the ones with a little fan on top? It says it reads in meters per second? How do set it or convert it to read litres per second at each outlet?

Ok so I’ve done a bit of measuring, not sure if I’ve done it right but here goes… Total volume of house = 213 m3 divide this by 3 to give min flow rate of 71 m3/hr from the table JohnMo supplied earlier for rules in wales, a 3 bed 4 person home requires a supply air of 76 m3/hr or 21 l/s im extracting from 2 rooms , a bathroom and a kitchen, which require 47 m3/hr 13 l/s and 29 m3/hr 8 l/s So my supply is 76 m3/hr and my extract is also 76 m3/hr (21 l/s) I’ve estimated my pressure drop on my longest branch of ducting is 61 pa. I’ve used the figures from the Nuaire catalogue for each piece of ducting and bends etc, they list pressure drops from 5 l/s to 80 l/s for every item so my system will be running at 21 l/s so I chose all the values they gave for 25 l/s, and I’ve ended up at 61 pa, the supply grille on this long branch was the biggest pressure dropper at 30pa (assuming 10mm opening) I then found the airflow performance curve on the Brookvent air cycle 1.2 Manual, if I follow 61 pa across the curve graph it says the unit will supply 60 l/s or 216 m3/hr or 127 cfm. (This would be speed 5 out of 5 I’m assuming?) if you then look at the acoustic chart, for the unit to output 60 l/s it would have to be on speed 5 out of 5, If I then turn the unit down to run at 21 l/s it should be at speed 2 out of 5 and have a decibel of 10 to 19 db at a 3 metre distance i hope all that makes sense! Do these figures sound ok?

That’s neat, thanks for that