Electric UFH vs Automation

[Thorfun]

1 hour ago, pocster said:

I put mine in in the loft near the access hatch . 

I was also thinking about putting them in the loft tbh.

1 hour ago, Nickfromwales said:

Stick them low level next to a hidden double socket. At least they blend in / are out of eyesight then  

definitely one to consider as well

[Pocster]

35 minutes ago, Thorfun said:

was also thinking about putting them in the loft tbh.

I’m right , 100% - just do it . 

[joth]

Putting them on the bulkhead above the bathroom door is popular, depending on door heights that's either right in view or well out of it 😅

 

Regarding UFH electric mats I had each wired in 2.5mm2 direct to the Loxone cabinet, where I control them from a cheap zero crossing SSR driven by a dmx decoder.

Originally I had the Schluter OEM controller (their most basic manual one) installed in the isolator switch locations, with the underfloor thermistors handled there, but these have a very annoying click every time the power up.

So I removed them completely and manage it all in Loxone: I extended the thermistor wires back to the Loxone cabinet (had put spare CAT6A in there just in case this was needed). It was fairly easy to determine the temperature curve for the thermistor and hook the  up to analogue inputs on the miniserver. So I now have a software PID controller block that manages getting the floor up to target temperature. Using SSR rather than mechanical relay is crucial for this, as it modulates the mat on/off every second or so which would be hell done mechanically.

 

The isolator locations are supposed to be "obvious" for someone working on the equipment. I'd hesitate to put them in the loft, my Loxone cabinet itself is on the same floor so much more obvious place to go than hunt around one floor up for it. 

Edited June 21, 2023 by joth

[Dan F]

11 hours ago, Thorfun said:

would the power for the electric ufh have to run all the way back to the loxone cabinet?

Thats what we did, using a standard Loxone cabinet-mounted relay output.

 

As for the temperature sensor, I extended the 1-wire loop to include sensors in the bathroom floors as well as in the ground-floor slab.

Edited June 21, 2023 by Dan F

[Dan F]

7 hours ago, Thorfun said:

that's actually quite tricky for us! we don't really have any cupboards that close tbh. we have the ufh and towel rails to spur. It will be a conversation I have with the sparky.

If you plan it carefully, you can put them behind a cabinet drawer.  To do this though, you need to know what cabinet you are getting and how high you plan to install it ahead of time.  In our cases, it's worked quite well, and while the isolators aren't super-easy to get to they are fully hidden but still accessible.  We have a fancy toilet in one bathroom and electric UFH and 12v heated towel radiators in all bathrooms, so up to three isolators in total.

Edited June 21, 2023 by Dan F

[Rob99]

I would recommend switching in the Loxone panel using a 16A relay with local isolation.

 

When I build panels for some clients they run several towel rails and/or bathroom UFH circuits back to the panel in 1.5mm2 T&E as radial circuits. These are switched in the panel and fed from one or more RCBO's in the DB, depending on loads.

[Thorfun]

1 hour ago, Rob99 said:

I would recommend switching in the Loxone panel using a 16A relay with local isolation.

 

When I build panels for some clients they run several towel rails and/or bathroom UFH circuits back to the panel in 1.5mm2 T&E as radial circuits. These are switched in the panel and fed from one or more RCBO's in the DB, depending on loads.

thanks. i think this is what i'll ask the sparky to do. local thermostats and controllers are expensive and we shouldn't need them.

 

but, just so i fully understand, when you say radial do you mean a single wire from cabinet to each towel rail and ufh mat? so for 3 x en-suites each with a towel rail and ufh that would be 6 cables in total? i sometimes get radial and ring mixed up as i'm a simple fella sometimes.

[Dan F]

3 hours ago, Thorfun said:

but, just so i fully understand, when you say radial do you mean a single wire from cabinet to each towel rail and ufh mat? so for 3 x en-suites each with a towel rail and ufh that would be 6 cables in total? i sometimes get radial and ring mixed up as i'm a simple fella sometimes.

 

Yes, that's what we have. 

 

What towel rails are you using? We used  12v ones which are nice, but this still meant 230v supply given run would have been too long for 12v.  These: https://www.thermosphere.com/products/bathroom/towel-bars.  (12v driver is hidden behind cabinet drawer along with isolators).

 

Temperature sensor using 1-wire?

Edited June 22, 2023 by Dan F

[Thorfun]

2 hours ago, Dan F said:

 

Yes, that's what we have. 

 

What towel rails are you using? We used  12v ones which are nice, but this still meant 230v supply given run would have been too long for 12v.  These: https://www.thermosphere.com/products/bathroom/towel-bars.  (12v driver is hidden behind cabinet drawer along with isolators).

 

Temperature sensor using 1-wire?

the wife bought the towel rails so I'm not sure what they are. pretty sure they're not 12V though. I would presume 1-wire sensors like I've got in the basement and ground floor screeds, none of which are yet to be wired up!

[BartW]

Standard UFH sensor probes from UFH suppliers are resistance based, so assuming they should be ok to wire to the analog input on the cabinet?

 

 

 

[joth]

1 hour ago, BartW said:

Standard UFH sensor probes from UFH suppliers are resistance based, so assuming they should be ok to wire to the analog input on the cabinet?

 

 

 

Yup that's what I did, as mentioned up thread. Probably would use 1-wire if planning it from scratch, but I was taking over control of UFH mat by removing the Schluter proprietary controller so had to work with what was already installed by the tiler. 

[BartW]

13 hours ago, joth said:

Yup that's what I did, as mentioned up thread. Probably would use 1-wire if planning it from scratch, but I was taking over control of UFH mat by removing the Schluter proprietary controller so had to work with what was already installed by the tiler. 

 

What benefit is there in using 1 wire sensors over the standard resistance probe?

 

 

[SteamyTea]

8 hours ago, BartW said:

 

What benefit is there in using 1 wire sensors over the standard resistance probe?

 

 

You don't need to take cable resistance into account and you do not need a ADC.

[BartW]

2 hours ago, SteamyTea said:

you do not need a ADC.

Which you have by default in loxone. 

[SteamyTea]

7 minutes ago, BartW said:

Which you have by default in loxone. 

And ESP8266/32s.

But not, annoyingly, in the RPi, but that is for historical reasons, not technical ones.

[joth]

3 hours ago, BartW said:

Which you have by default in loxone. 

But only 4 of them. My house has nearly 20 temperature probes, and this is not counting instrumentation built into light switches, MVHR and ASHP.

Additional AIs are 30+VAT per channel and then you have to deal with some being voltage sensing, some current sensing. The 1-wire are plug and play in comparison (if you keep the wiring clean)

 

Fortunately I only have 2 UFH mats with thermistors so was easy enough to wire these direct to the miniserver (biased with appropriate ladder resistor to keep the thermistor to 0-10V despite me driving it from 24V.). That plus figuring out a calibration curve was much more hassle than 1-wire sensors. 

 

 

 

 

Edited June 24, 2023 by joth

[Rob99]

On 22/06/2023 at 14:55, Thorfun said:

but, just so i fully understand, when you say radial do you mean a single wire from cabinet to each towel rail and ufh mat? so for 3 x en-suites each with a towel rail and ufh that would be 6 cables in total? i sometimes get radial and ring mixed up as i'm a simple fella sometimes.

Apologies for the late reply, been a busy few days!!

 

Yes, a single t&e cable for each towel rail and UFH back to the cabinet. 

 

Generally in the UK everyone uses ring mains for socket outlet power circuits and radial circuits for others (e.g. oven, shower, lighting, immersion etc etc)

 

Don't know how true this is but on an electrical course a few years back the trainer told us that ring mains are a peculiar british thing, having been conceived in the 1950's as a way to provide power outlets using less (and thinner) cable than radials as copper was in short supply. Before that all circuits were radial and I think pretty much we are one of the few, if not the only, country that does it this way.

[Thorfun]

35 minutes ago, Rob99 said:

Apologies for the late reply, been a busy few days!!

 

Yes, a single t&e cable for each towel rail and UFH back to the cabinet. 

 

Generally in the UK everyone uses ring mains for socket outlet power circuits and radial circuits for others (e.g. oven, shower, lighting, immersion etc etc)

 

Don't know how true this is but on an electrical course a few years back the trainer told us that ring mains are a peculiar british thing, having been conceived in the 1950's as a way to provide power outlets using less (and thinner) cable than radials as copper was in short supply. Before that all circuits were radial and I think pretty much we are one of the few, if not the only, country that does it this way.

cheers. got it. for our mains we have gone a hybrid solution and have a ring per room. with the cost of RCBOs have a purely radial setup would've been crazy money! our sparky is back in a week or so and I'll let him know my latest change of plan! he loves it when I do that. 🤣

 

now I need to research electric ufh mats.....

[Dan F]

19 hours ago, Thorfun said:

now I need to research electric ufh mats.....

A lot come with temp sensor and controls, try to get one that's just the mat.  Enhabit recommended "rayotec 150w/m2" in our m&e spec.

[jack]

On 21/06/2023 at 12:44, Nickfromwales said:

What outputs can the Loxone give? Zero volt switching or 230v out? How many amps per 'channel' etc? The UFH mats will be using very little power tbh, so just treat it as a lighting circuit and run from the 3a switched fused spur (you'll need to retain a means of local isolation) back to the HA cabinet? Saves a relay, but the relay may be the cheaper option. Just remember to go solid state, or you'll have clicking noises coming from the relay which may have been better left at the HA cabinet  

 

You can run whatever you need.

 

I can't remember the current ratings of the different extensions, but I vaguely recall that some are physical relays and some are solid state. I use some for zero volt switching and others for mains switching. You can also use low them to switch low voltage DC and use that to drive a chunky relay if needed.

[Thorfun]

1 hour ago, Dan F said:

A lot come with temp sensor and controls, try to get one that's just the mat.  Enhabit recommended "rayotec 150w/m2" in our m&e spec.

Our tiler said to get 100W/m² mats. Been looking at the Warmstar ones from eBay that others have on here. 

[Alan Ambrose]

>>> at the Warmstar ones from eBay that others have on here.

 

Just a warning - these are, of course, a bug... nuisance if they fail.  Buy the best quality ones. How do I know that?

[Nickfromwales]

3 hours ago, Dan F said:

A lot come with temp sensor and controls, try to get one that's just the mat.  Enhabit recommended "rayotec 150w/m2" in our m&e spec.

That’s a bit OTT? 50-100w max for anything built to ‘low energy’ standards should be ample as the ambient is never that far away from the desired ‘comfort’ temps. 
I only used to install 150w or above when this was the only heat source in the room ( for a crappy b.regs refurb ). 

[Thorfun]

1 hour ago, Alan Ambrose said:

>>> at the Warmstar ones from eBay that others have on here.

 

Just a warning - these are, of course, a bug... nuisance if they fail.  Buy the best quality ones. How do I know that?

how do you know what is good quality? surely they're all made in the same factory in China?

[SteamyTea]

3 hours ago, Thorfun said:

how do you know what is good quality? surely they're all made in the same factory in China?

Yes, it is a problem now.

Mind you, not all Chinese made stuff is bad, they have very good engineers there.