MVHR newbie.. help needed

[PeterW]

North side on the OP faces a road @joe90

[joe90]

Just now, PeterW said:

North side on the OP faces a road @joe90

 

AH, missed that ?

[Savage87]

As a quick update, I have settled for a Nuaire MRXBOXAB-ECO2 unit which is more or less identical with the Domus HRXE unit that I was looking to buy initially.

I'm going for Airflow Airflex PRO 75mm radial ducting. BPC says that this is the best duct to use in a radial system because it's more flexible that other brands and it's anti static and anti bacterial lined. Good idea or just another sales technique?

 

I would like to know how many of you have visual controls for your units?

I would like to buy the https://xpress.nuaire.co.uk/mrxbox-vsc-wall-mounted-lcd-touch-screen-controller/ just so I can see what's going on with the unit and have the extra features that come along with it. It's over 200 pounds and don't know if it's worth it. I wouldn't want to buy it and then realise that I could have live without it.

[MikeGrahamT21]

I haven't got MVHR yet, but I also plan to get to radial anti-static and anti-bacterial ducting. I have read articles in the past in building magazines about nasty bugs being found in ducting of MVHR due to the temperatures which run through it, so I would say its critical personally, and for the little extra outlay should be worth it. Anti-static should prevent dust from sticking to the inside of ducting in theory, it will still get there, but should be much reduced.

 

I too keep looking at fancy controllers, in fact i've actually made it one of the things on my wish list, but in reality I dont think they are needed, I'm pretty sure a good MVHR unit should be a fit and forget solution, which shouldn't require controlling if its setup correctly, many have sensors built in to handle differing conditions, I suppose the only thing which is useful is the filter change reminder, but you could set a reminder on your phone as its based on operating hours.

 

Perhaps a unit which connects to your phone rather than has a control panel may be a better option, but these are hard to come by at the minute.

[JFDIY]

As I've mentioned in another thread, I went for vent-axia because of the controls functions, seemed to be way ahead of most of the others yet simple. 

 

Main thing for me is looking at mvhr all started due to the cost and disruption of getting an extractor over an island hob. The vent-axia unit I chose has a cooker mode which, via switch in kitchen will turn on to 100% extract and only 30% supply, you can change these figures to whatever you like though within reason. Critical thing is it opens the summer bypass to prevent fouling of the heat exchanger.

 

It also humidity controlled which now fitted seems brilliant, jump in the shower and senses the moisture incredibly quickly and it progressively self manages the flow rates. I've wired in boost capability to the lights in the shower, but in retrospect it wasn't needed.

[Pocster]

22 minutes ago, JFDIY said:

As I've mentioned in another thread, I went for vent-axia because of the controls functions, seemed to be way ahead of most of the others yet simple. 

 

Main thing for me is looking at mvhr all started due to the cost and disruption of getting an extractor over an island hob. The vent-axia unit I chose has a cooker mode which, via switch in kitchen will turn on to 100% extract and only 30% supply, you can change these figures to whatever you like though within reason. Critical thing is it opens the summer bypass to prevent fouling of the heat exchanger.

 

It also humidity controlled which now fitted seems brilliant, jump in the shower and senses the moisture incredibly quickly and it progressively self manages the flow rates. I've wired in boost capability to the lights in the shower, but in retrospect it wasn't needed.

Which model have you got ?

[JFDIY]

Kinetic B plus.

 

Looking at the installation and commissioning document though the same control board and logic should be on;

 

Kinetic B

Kinetic BH

Kinetic FH

Kinetic B Plus

Kinetic high flow

 

 

[Pocster]

5 minutes ago, JFDIY said:

Kinetic B plus.

 

Looking at the installation and commissioning document though the same control board and logic should be on;

 

Kinetic B

Kinetic BH

Kinetic FH

Kinetic B Plus

Kinetic high flow

 

 

I ask because I have the as of yet unused kinetic sentinel and I don’t remember a “ hob extractor mode “ - which sounds dead handy - so I’m jealous!!

[Bitpipe]

23 minutes ago, pocster said:

I ask because I have the as of yet unused kinetic sentinel and I don’t remember a “ hob extractor mode “ - which sounds dead handy - so I’m jealous!!

 

We have that as well on our Sentinel but it proved too fussy to implement - would have needed a current detector on the CH supply to trigger the dedicated terminal on the MVHR controller.

 

Didn't want a dedicated switch as all of our MVHR boost is automatic - motion detectors in bathrooms & also triggered by light switches in bathrooms plus the RH detector in the unit itself. 

 

We have a MVHR controller in the utility so I just nip in and hit the boost there - although don't get the benefits of the dedicated CH mode.

[Pocster]

2 minutes ago, Bitpipe said:

 

We have that as well on our Sentinel but it proved too fussy to implement - would have needed a current detector on the CH supply to trigger the dedicated terminal on the MVHR controller.

 

Didn't want a dedicated switch as all of our MVHR boost is automatic - motion detectors in bathrooms & also triggered by light switches in bathrooms plus the RH detector in the unit itself. 

 

We have a MVHR controller in the utility so I just nip in and hit the boost there - although don't get the benefits of the dedicated CH mode.

Yes I was going to use movement and humidity sensors to trigger the boost .

As I’ll have lots of home automation stuff I don’t think it would be too tricky to have the induction hob trigger the mvhr . Will play with that later I.e a year from now ?

[Bitpipe]

19 minutes ago, pocster said:

Yes I was going to use movement and humidity sensors to trigger the boost .

As I’ll have lots of home automation stuff I don’t think it would be too tricky to have the induction hob trigger the mvhr . Will play with that later I.e a year from now ?

 

We use the same circuit to trigger the DHW return loop pump so that when you walk into the room there is hot water near the tap when you need it.

[Pocster]

Just now, Bitpipe said:

 

We use the same circuit to trigger the DHW return loop pump so that when you walk into the room there is hot water near the tap when you need it.

Assume I don’t need to do this with a Uvc ?

[Dreadnaught]

24 minutes ago, pocster said:

I’ll have lots of home automation stuff

 

I wonder, do you think it might be possible to trigger the "away" low ventilation rate when you leave home using a smartphones geofencing?

 

(On iOS, I already have a setup whereby the lights turn off when the last person leaves home. It might be nice to reduce the ventilation rate similarly too.)

[Pocster]

4 minutes ago, Dreadnaught said:

 

I wonder, do you think it might be possible to trigger the "away" low ventilation rate when you leave home using a smartphones geofencing?

 

(On iOS, I already have a setup whereby the lights turn off when the last person leaves home. It might be nice to reduce the ventilation rate similarly too.)

Can’t see why not . I was intending using geo fencing to unlock the front door as you approach- but that might be a bit of a security risk . Really need facial recognition.

[Bitpipe]

16 minutes ago, pocster said:

Assume I don’t need to do this with a Uvc ?

 

It's a way of preventing water going cold in the pipework and reducing time to hot water at tap so independent of the storage system I think - basically a return loop to DHW storage with a pump that's either temp/timer driven or occupation etc..

[Pocster]

2 minutes ago, Bitpipe said:

 

It's a way of preventing water going cold in the pipework and reducing time to hot water at tap so independent of the storage system I think - basically a return loop to DHW storage with a pump that's either temp/timer driven or occupation etc..

I see .

Does it make that much difference?

I assume it saves a few seconds on making a hot tap hot ??

[Oldsteel]

In my last house build (okay it was 10 years ago) the MVHR was the best investment I made. Reading all the above posts has highlighted many things about the installation I took for granted at the time:

1. It had the silver flexible pipes on all connections to the unit which led onto rigid ducting throughout the house. I didn't realise they were silencers! 

2. It was mounted in the loft but not directly on the ceiling, but on two A-frame horizontal joists. I plan to do the same - if there is no available joist I would add it just to mount the unit.

3. It was an Orcon HRV unit and ran silently, with the loft door closed we never heard it in operation on any setting anywhere in the house

4. It had no remote controls at all. It was a 'set and forget' on the internal control board dip switches. 

5. Its humidity sensors only worked for about 2 years. When I tried to get replacements they implied the things never worked properly and they stopped supplying spares. Might it still be the case that humidity sensors are flaky?

6. It did need an annual clean/service/filter change. In spite of pretty dense filters dirt built up over time on the fan blades which were a b*ger to clean.

 

I am now planning to install an MVHR in the next house and love the idea of the PIR to control the velocity in the bathrooms - and the DHW return pump! In the last house the DHW return pump was on a timer and although very convenient was probably quite inefficient. I am looking forward to much smarter MVHR controls in the next build. The interaction between MVHR and kitchen extractors has been covered in other threads, IMO you can't rely on increased velocity MVHR to take the place of the extractor, it simply wont be powerful enough. 

[SteamyTea]

1 minute ago, Oldsteel said:

When I tried to get replacements they implied the things never worked properly and they stopped supplying spares.

Are they DHT11s, these are rubbish.

The DHT22s are a lot better.

[Oldsteel]

4 minutes ago, SteamyTea said:

Are they DHT11s, these are rubbish.

The DHT22s are a lot better.

 

Sorry I have no idea, moved out of that house 2 years ago!

[SteamyTea]

38 minutes ago, Oldsteel said:

moved out of that house 2 years ago

Then can I go around and change them for 100 quid, they cost about a quid each.

 

[joth]

1 hour ago, Dreadnaught said:

 

I wonder, do you think it might be possible to trigger the "away" low ventilation rate when you leave home using a smartphones geofencing?

 

(On iOS, I already have a setup whereby the lights turn off when the last person leaves home. It might be nice to reduce the ventilation rate similarly too.)

So long as you never have any guests over to stay while you pop out for the day this might be fine. For me it'd be a total non-starter.

IMHO the best signal for "away" mode energy saving modes is to use the burglar alarm activation. Even if you don't have a burglar alarm as such, having some kind of big red button you hit on leaving the house (and, next to the bed before going to sleep) has value in turning off all the lights, closing curtains, turning down the heating/HW schedule, warning if the back door is still open, enabling away-from-home automatic light routines,  etc etc. Any door or motion sensor can be used as a trigger for returning to occupied state (or... setting off the alarm).

Why involve phones and cloud connections for anything that can be done purely locally, and in a way that supports all users of the house (not just those with the app installed)? 

 

 

[SteamyTea]

3 minutes ago, joth said:

has value in turning off all the lights, closing curtains, turning down the heating/HW schedule, warning if the back door is still open, enabling away-from-home automatic light routines,  etc etc. Any door or motion sensor can be used as a trigger for returning to occupied state (or... setting off the alarm).

With all the energy to drive that lot, be better off just opening a window.

[Pocster]

16 minutes ago, joth said:

So long as you never have any guests over to stay while you pop out for the day this might be fine. For me it'd be a total non-starter.

IMHO the best signal for "away" mode energy saving modes is to use the burglar alarm activation. Even if you don't have a burglar alarm as such, having some kind of big red button you hit on leaving the house (and, next to the bed before going to sleep) has value in turning off all the lights, closing curtains, turning down the heating/HW schedule, warning if the back door is still open, enabling away-from-home automatic light routines,  etc etc. Any door or motion sensor can be used as a trigger for returning to occupied state (or... setting off the alarm).

Why involve phones and cloud connections for anything that can be done purely locally, and in a way that supports all users of the house (not just those with the app installed)? 

 

 

Geofencing I would do locally as with most things . Other advantage is you could tell whom is in the house and possibly with more beacons which room they are in .

[SteamyTea]

Can't you just set up a small, cheap computer that has Bluetooth, when it detects a known Bluetooth signal with a registered MAC address, it then can do what you want it to do.

Might even be able to use those cheap 'lost luggage and car keys' Bluetooth fobs to activate it.

[Pocster]

15 minutes ago, SteamyTea said:

Can't you just set up a small, cheap computer that has Bluetooth, when it detects a known Bluetooth signal with a registered MAC address, it then can do what you want it to do.

Might even be able to use those cheap 'lost luggage and car keys' Bluetooth fobs to activate it.

Yes ; that’s what a raspberry pi beacon is .