MVHR newbie.. help needed

[SteamyTea]

Just now, pocster said:

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

I may have to make one, but without the Crapple code.

[Jeremy Harris]

33 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.

 

 

That's how Tesla's lock, unlock and start now.  They detect BT at a range of about a metre, and unlock, set the driver profile, etc, so by the time you've opened the door and climbed in everything has booted and is running.  They do the reverse when you get out, detect that your BT device is outside the vehicle, shut everything down and lock the doors.

 

This needed a BT enabled device ('phone, tablet etc) either Apple or Android, but they've now released a hands-free remote that does the same thing.  It seems to just have a very low power BT device that works the same way as a 'phone, with the same sort of encryption, that's just paired to the car, like any other BT device.  Supposed to be secure and immune from a relay attack, although whether this remains true is anyone's guess, knowing how good hackers are at busting into stuff like this.

[SteamyTea]

2 minutes ago, Jeremy Harris said:

Supposed to be secure and immune from a relay attack

Someone will find a way around it I am sure.

 

[Dreadnaught]

A new technology coming to mobile devices soon (already in the latest iPhones and maybe non-Apple ones too, I don't know) is a more accurate way of positioning devices in 3D space. It is known as Ultra Wideband (UWB). Rather than measuring signal strength it measures round-trip time. I suspect it will have a wider and a more fundamental impact that we can presently predict. It could, for example, allow highly precise indoor mapping. I suspect home automation will eventually be transformed by it.

 

The technology adoption cycle: the impact of technology is generally over estimated in the short term but under estimated in the long term.

[Jeremy Harris]

6 minutes ago, SteamyTea said:

Someone will find a way around it I am sure.

 

 

 

So am I, if for no other reason than the fact that Tesla's attract geeks who like nothing better than to find flaws in their systems.  The fact that the car runs on Linux, though, and that much (supposedly all) of the code is open source means that there are a lot of people playing around, amongst both the white and black hat fraternities, so as long as the white hats are better than the black hats things should be OK.

 

As an aside, I've just finished getting a Raspberry Pi Zero W to work as a USB drive, that will automatically dump TeslaCam files (both DashCam and SentryMode) to my home file server as soon as the car is within range of our wifi network.  It also stores all my music files, and keeps them synced to a directory on the file server, so the car will always have an up to date version of my music library onboard.  Premature, really, as I don't get to test it until I get the car on Friday...

[Bitpipe]

3 hours ago, pocster said:

I see .

Does it make that much difference?

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

 

It does make a difference as the wait is typically more than a few seconds.

 

In our house, if I'm in the kitchen running the tap in the morning (before the boost/dhw return pump is running), it can be a good 2-3 mins before I get decent hot water to wash up - it's not even coming that far.  If I've triggered the pump by using a bathroom, its a few seconds.

 

I suppose it depends on your plumbing schema but I know @jack didn't do it (we used same plumber) and he does regret it. Not expensive really, price of a pump and a few extra m of piping.

 

[Oz07]

What's the advantage of pir detector in bathrooms if your light is switched. Can't these units be linked to the light switch to boost when on?

[Bitpipe]

Just now, Oz07 said:

What's the advantage of pir detector in bathrooms if your light is switched. Can't these units be linked to the light switch to boost when on?

 

In daytime I don't need to put the bathroom light on (aside from the downstairs WC which is windowless) so we used either to trigger the boost/DHW return pump.

 

Electrician explained how he did it, something to do with chaining all the neutrals together  - wasn't expensive, just needed to get it in on first fix. 

[Oz07]

Good point

[Pocster]

4 minutes ago, Bitpipe said:

 

It does make a difference as the wait is typically more than a few seconds.

 

In our house, if I'm in the kitchen running the tap in the morning (before the boost/dhw return pump is running), it can be a good 2-3 mins before I get decent hot water to wash up - it's not even coming that far.  If I've triggered the pump by using a bathroom, its a few seconds.

 

I suppose it depends on your plumbing schema but I know @jack didn't do it (we used same plumber) and he does regret it. Not expensive really, price of a pump and a few extra m of piping.

 

Ok . I’ll bare that in mind . No idea how I would implement it in my configuration- but I haven’t got any hot water to test yet anyway !

[Bitpipe]

12 hours ago, pocster said:

Ok . I’ll bare that in mind . No idea how I would implement it in my configuration- but I haven’t got any hot water to test yet anyway !

 

Some here have gone for a manifold distribution approach (where there would be a lower bore return path for DHW to the tank from the manifold - this ensures the manifold is always hot and you then only have the leg to each room to consider.

 

We have a radial system which tees off to each outlet as it passes but after the last room, the DHW pipe reduces to 15mm and returns to the DHW tank.

 

 

[jack]

13 hours ago, Bitpipe said:

I suppose it depends on your plumbing schema but I know @jack didn't do it (we used same plumber) and he does regret it.

 

Correct. I was concerned about energy wastage and overheating rather than cost, but have since learned that these probably aren't large issues.

 

The two main problem areas are our kitchen sink and one of the bathroom sinks. It takes about 45 seconds for the water in the kitchen to start getting warm. If I'm in a hurry and can't wait I sometimes end up using the hot water tap.

 

The bathroom sink is an oddity. The shower in the same room takes less than 5 seconds to start running warm. The sink takes nearly a minute. They're both very close to the plant room underneath, so I have no idea what odd route the sink plumbing must take!

 

The other place I'd have included this is the downstairs toilet, which takes over 30 seconds to start warming up. No-one will wait that long, so it's cold water for hand-washing there.

[Savage87]

I don't like the idea of having the control panel, it's just only option that I have to make the unit smarter, I would have loved an app but the manufacturer doesn't have a bridge or app. I'm planning to hack the unit anyway with some home automations and relays via a microcontroller ? . I just want to be able to control temperature for the summer bypass and I also want to see the temperature from the supply end extract ducts. The unit has a built in humidistat but I'm not going to rely on it, I have a DHT22 in my bathroom and that triggers my extract fan at the moment.

[Savage87]

Does anyone have any left over radial duct?

I'm looking for any length of Airflow Airflex PRO 75mm red duct 9041130

[MJNewton]

I've got some. How much do you need / what for? It sounds like you might just need a very short length - happy to pop some in the post. 

Edited November 21, 2019 by MJNewton

[Pocster]

On 20/11/2019 at 08:50, Bitpipe said:

 

Some here have gone for a manifold distribution approach (where there would be a lower bore return path for DHW to the tank from the manifold - this ensures the manifold is always hot and you then only have the leg to each room to consider.

 

We have a radial system which tees off to each outlet as it passes but after the last room, the DHW pipe reduces to 15mm and returns to the DHW tank.

 

 

Still can’t visualise how this is plumbed up .

[PeterW]

1 hour ago, pocster said:

Still can’t visualise how this is plumbed up .

 Back to the hot return port on the tank - usually about 250mm down from the top 

[Pocster]

11 minutes ago, PeterW said:

 Back to the hot return port on the tank - usually about 250mm down from the top 

I still don’t get how this works .

if a pipe is full of cold water how is that ‘pumped’ out and replaced with hot ?

Sorry if I’m being thick and unskilled ?

Edited November 23, 2019 by pocster

[PeterW]

15 minutes ago, pocster said:

I still don’t get how this works .

if a pipe is full of cold water how is that ‘pumped’ out and replaced with hot ?

Sorry if I’m being thick and unskilled ?

Ok... so ...

 

Hot comes off the top of the tank down an insulated 22mm  pipe, and then is tee’d off to each tap as close as you can get. After the last tap spur, it drops to 15mm or even 10mm and then returns to the tank via either a bronze or polypropylene bodied pump (due to it being potable  water).

 

Hot return port is here on a Telford Heat Pump cylinder. 

 

 

 

This pump runs intermittently to draw a slug of hot water from the tank, and then return the cooler water to the tank. Essentially this whole circuit is just a pressurised extension of the tank. 
 

When a tap is opened then the water pressure takes over and taps operate as normal but the only “cold” water is the last leg from the circulating loop to the tap.  

[Pocster]

44 minutes ago, PeterW said:

Ok... so ...

 

Hot comes off the top of the tank down an insulated 22mm  pipe, and then is tee’d off to each tap as close as you can get. After the last tap spur, it drops to 15mm or even 10mm and then returns to the tank via either a bronze or polypropylene bodied pump (due to it being potable  water).

 

Hot return port is here on a Telford Heat Pump cylinder. 

 

 

 

This pump runs intermittently to draw a slug of hot water from the tank, and then return the cooler water to the tank. Essentially this whole circuit is just a pressurised extension of the tank. 
 

When a tap is opened then the water pressure takes over and taps operate as normal but the only “cold” water is the last leg from the circulating loop to the tap.  

Really helpful @PeterW - nearer the time to implement this ill post photos to make sure I’m doing it right . But in essence it sounds quite simple ; appreciated.

[Bitpipe]

The usual way to trigger the pump is via a timer and pipe stat close to the return to the tank. ie during the timed period if the water starts to cool in the pipe the pump runs and keeps it hot.

 

So there is some heat leakage but if all is well insulated then it won’t have a massive impact.

[mvincentd]

On 19/11/2019 at 09:13, MikeGrahamT21 said:

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.

My Zender q350 does this, and i'm addicted to constantly checking the external/supply/extract/exhaust air temperatures with it.  It's been really interesting as we've used no other heating so far, so to see how effective mvhr is (beyond expectations) at maintaining fresh but warm air.

 

 

@pocsterhot return is pipe out of tank bottom right in pic, goes through red lever into brass pump, above that is (i think its called a thermal switch?) white box monitoring pipe temp....when pipe cools to a set temp it triggers pump (except its wired via a timer too so it'll only pump at set times).

Edited November 23, 2019 by mvincentd
add pics.

[MikeGrahamT21]

On 23/11/2019 at 23:17, mvincentd said:

My Zender q350 does this, and i'm addicted to constantly checking the external/supply/extract/exhaust air temperatures with it.  It's been really interesting as we've used no other heating so far, so to see how effective mvhr is (beyond expectations) at maintaining fresh but warm air.

 

 

@pocsterhot return is pipe out of tank bottom right in pic, goes through red lever into brass pump, above that is (i think its called a thermal switch?) white box monitoring pipe temp....when pipe cools to a set temp it triggers pump (except its wired via a timer too so it'll only pump at set times).

 

I'm sure you'll check it less once the novelty has worn off, i've been the same with heating controls and solar generation, but its dropped off more recently. Really interesting hearing people talking about how the MVHR helps greatly with holding temperatures, an effect i didn't realise would be so pronounced. I'm considering installing a unit here next year, or possibly year after depending what happens in the coming 6 months, though i'm not expecting such great efficiencies, as I'm far from airtight at the moment (Only 2 rooms and a hallway is truly airtight at present, another 5 larger rooms still need doing, though only one out of those is really poor for airtightness).

[Adsibob]

On 23/10/2019 at 10:01, vivienz said:

Be cautious about where in the loft you put the unit. Ours is in our loft space, directly above the en suite to our bedroom and even on a low flow speed it sounds like a ship's engine. Additional sound proofing may have made a difference but our contractor didn't finish the job so I will see if we can get it done as a retrofit and report back with any improvements.  Much of the noise from ours is from the MVHR unit itself rather than the ducts and vents - these are compratively quiet.

@vivienz did you ever manage to retrofit the sound proofing? Did it make a difference? Also, out of interest, what MVHR unit do you have?

[Russdl]

@Adsibob Vivien won’t be around to answer (it’s a long story). 
 

I’m pretty sure she had an Ecocent Air MVHR. These units have an integrated heat pump so can provide an element of heating and cooling. I was interested in them at one point and speaking to the designer he did say they can be a bit noisy especially when the heat pump is operating and he suggested that the best way to isolate the unit was to place it on sandwich of aluminium sheet and that rubber stuff you find in kids playgrounds, repeat as necessary until the problem has gone. I passed that on to Vivien but no idea if she did that or not, perhaps I’ll give her a call to find out.