UFH - Actuators per zone

[Red Kite]

Hi,  I have installed Wunda UFH with a 4 port and 10 port manifold (lots of loops to keep the loop length to 100m max } and am now looking at thermostats, control and wiring boxes etc. I am looking at products from from Wunda and Heatmiser and was planning to use the Salus Autobalance actuators. The Wunda box says max of 4 actuators per zone and the Heatmiser specs 6 per zone. I would ideally like to control the system with a small number of thermostats {likely 2 or 3}  but the actuators per zone limit seems to require more thermostats. Have I got this right? - and why is there a limit anyway - how much current does an actuator take and why cant I just wire more actuators in parallel? Or does anyone know of a wiring box that allows more actuators per zone?

 

Any thoughts?

[PeterW]

The control units are limited to the current required to support that many actuators. The wiring units aren’t dumb units hence the restrictions. Heatmiser are crap IMO and I would avoid anyway. 

[JFDIY]

Don't think all heatmiser thermostats and wiring centers will work with the salus auto balancing actuators. (According to wunda's website)

 

You could wire one thermostat to control two channels in the wiring centre. Each channel can them control say 4 actuators.

 

 

[Red Kite]

Many thanks, is there any consensus on Heatmiser? I was looking at them because I wanted the future option to go for Internet control {IoT: the Internet of Toys} and I cant see a way to do this with Wunda - they say they do WundaSmart but I cant see any products that I can buy on their website. Are there other good alternatives anyone has used? That play nicely with Salus?

 

@JFDIY  wiring multiple channels to the wiring centre is the obvious solution - brilliant! Why didn't I think of that? I had thought it wouldn't work with Wireless but Wunda specifically say you can pair a single thermostat to multiple channels. I will check if this is the case with Heatmiser.

Thanks

[JFDIY]

I went for emmeti,manifolds and controls but will use the salus auto-balancing actuators. I chose them mainly because I could use a local supplier, anyway the emmeti zona thermostats are supposed to be connectable to the internet/smart phone app, but I do not plan to use that function.

[ProDave]

I doubt there is a real restriction, just some bean counter put a random figure in the user manual.

 

I use a cheap and cheerful "no name" UFH controller something like this https://www.ebay.co.uk/itm/8-zone-wiring-centres-Underfloor-Heating-Centre-Water-UFH-Systems/322282677792?epid=1549854398&hash=item4b098b6620:g:VBsAAOSwpLNX86pn

 

You can see each zone is switched by an individual relay. Those relays are rated at 2A or probably more.  With each actuator only drawing about 20W you could comfortably drive 10 actuators from each zone if you really wanted to.  The issue you would have is connecting that many actuators into the terminals provided but it would be easy to make your own junction box to join them together with 1 pair of wires to the UFH controller. That is probably why they only state a few actuators can be used on each zone.

 

I prefer to stick with simple no nonsense no gimmicks items like this. Some of the more expensive units will tie you into using particular thermostats for instance if you are not careful.

[PeterW]

5 hours ago, Red Kite said:

Many thanks, is there any consensus on Heatmiser? I was looking at them because I wanted the future option to go for Internet control {IoT: the Internet of Toys}

IoT stands for Introduction of Trouble in my book - I’ve still yet to find the person that needs to be able to change their bathroom UFH setting whilst sat at a Starbucks with a soya latte ....

 

UFH is far from real time feedback, and response time is measured in hours usually so I think the “connected” stats are a solution looking for a problem rather than anything of real world benefit. 
 

There is a significant benefit for using off the shelf components where they need to be used by more than one person unless you plan to write a controls manual for the house and give everyone a copy who walks through the door. 

[PeterW]

4 hours ago, ProDave said:

You can see each zone is switched by an individual relay. Those relays are rated at 2A or probably more.  With each actuator only drawing about 20W you could comfortably drive 10 actuators from each zone if you really wanted to. 

There are plenty of two and three zone controllers out there that can switch 10A per channel, and a simple thermostat in each circuit gives time and temperature control to the UFH. 
 

Using the stat on the buffer means that you can also negate the UFH/ASHP interlock and put the buffer in the driving seat and reduce short cycling as the tank stat will smooth out the demands as the zone actuators open up and close down. 
 

I’ll see if I’ve got the control circuit drawn up for mine - it uses W Plan wiring with a modification to allow the pump to be run without heating the floor (if I enabled cooling for example) 

[Fly100]

On 23/07/2020 at 06:19, JFDIY said:

Don't think all heatmiser thermostats and wiring centers will work with the salus auto balancing actuators. (According to wunda's website)

 

You could wire one thermostat to control two channels in the wiring centre. Each channel can them control say 4 actuators.

 

 

 

On 23/07/2020 at 08:05, Red Kite said:

Many thanks, is there any consensus on Heatmiser? I was looking at them because I wanted the future option to go for Internet control {IoT: the Internet of Toys} and I cant see a way to do this with Wunda - they say they do WundaSmart but I cant see any products that I can buy on their website. Are there other good alternatives anyone has used? That play nicely with Salus?

 

@JFDIY  wiring multiple channels to the wiring centre is the obvious solution - brilliant! Why didn't I think of that? I had thought it wouldn't work with Wireless but Wunda specifically say you can pair a single thermostat to multiple channels. I will check if this is the case with Heatmiser.

Thanks

I emailed Salus Tech Support yesterday and they say there are no issues and they will work.

 

Fly

[recoveringbuilder]

1 hour ago, Fly100 said:

 

I emailed Salus Tech Support yesterday and they say there are no issues and they will work.

 

Fly

Yes we have the heatmiser and the salus auto balancing actuators and they work fine 

Edited August 31, 2020 by Christine Walker
Correction to spelling

[Fly100]

12 minutes ago, Christine Walker said:

Yes we have the heatmiser and the salus auto balancing actuators and they work fine 

 

Have you seen an improvement / running cost reduction ?

[recoveringbuilder]

11 minutes ago, Fly100 said:

 

Have you seen an improvement / running cost reduction ?

Yes definitely an improvement, we had a few problems before with cold spots , downstairs bedroom was one of them that never seemed to get to its required temperature but all sorted now, don’t know about running costs we’ll see how it performs over the winter.