DHW and heating controls

[James94]

Due to start first fix plumbing soon, I’m having a 32kw system boiler & 300L UVC. UFH downstairs and radiators upstairs controlled by smart trv’s. In my quote from wunda they have included smarthub v3 with smart thermostats and probes.

 

Im looking for any advice and recommendations on which system does the best job and is most user friendly when it comes to control DHW, UFH and smart trv’s. 
 

will I need a thermostat with probe in each zone to control the UFH by an app?

James 

 

[JohnMo]

How well insulated is your house first as it makes a big difference.

[James94]

The house is fairly well insulated with B&B floor, the depth we have to ff level we are only able to fit 110mm pir in plus 55mm liquid screed.

 

and when I say smart I mean app controlled trv’s.

Edited January 28, 2022 by James94

[NewToAllOfThis]

Hi James,

 

I am doing something very similar, with UFH ground floor and radiators upstairs, not installed yet so can't say if it is the correct decision

 

After viewing some youtube videos and talking to Wunda, I am going with two manifolds, one for the UFH and one for the radiators. Each radiator will be fed separately from a port on the manifold although you could feed each room off one port if you have more than one radiator per room.

 

Going with this solution as easy to drain each radiator individually if required,

Room thermostats to control temperature of upstairs rooms rather than TRV's,

Running plastic pipe to each radiator so no joins to worry about,

It can all be controlled by a single app

 

Will it all work and was it a good decision, who knows, has anyone else taken a similar approach ?

 

 

[Beckside]

Buy Viessman W200 system boiler and run weather compensation. All the controls you need are in the boiler. 
ideally you would use mixing valves, which alter the flow temps, so no need for mixing or pump at the manifolds. I have a 32kw system boiler, 300lt UVC, two mixed circuits for dug, one unmixed for rads on a manifold. Priority hot water. No thermostats anywhere. House sits at a steady temp all the time, very comfortable, no big temp swings. Boiler modulâtes down to 1.8kw, highest flow temp into Ufh has been 32degC, house at 21. Much better than on/off controls. I was going to use Heatmiser, with thermostat in every room and two wiring centres. So saved on buying that lot, and less complexity, plus all the control software is in boiler so covered by the boiler warranty, which is 13 years.

the mixers are not cheap but it works really well 

[PeterW]

26 minutes ago, Beckside said:

so no need for mixing or pump at the manifolds

That is not good advice. I would never spec or install without - you lose all zone control and you will get hot spots and poor boiler modulation. 
 

27 minutes ago, Beckside said:

No thermostats anywhere

So this doesn’t meet building regs which require temperature controls. 

[Beckside]

Hi Pete,

regarding zone control, I have three zones, basement workshop ufh, house ground floor ufh, upstairs rads and towel rads. These zones are controlled by the software and touchscreen on the boiler. Each zone has its own timing and temp adjustments. The mixing valves each have their own pump. The boiler pump supplies the low loss header and the uvc. It is a four pipe system. Works well on weather comp with no stats. It maintains a pretty accurate temp. The system was chosen as the boiler has the widest modulation on the market. It routinely runs at 10-12% of its output. There are no hot spots.

the whole point of WC is to smooth out the delivery of heat, so running at a lower temp but for longer burn times due to the ability to modulate down to 1.8kw output.

Unless you have a huge buffer tank I don’t see how on/off controls can prevent excessive cycling of the boiler and over shoots of the room temps. Having boilers feed 70 deg water to manifolds only to blend it down to 30-40 deg seems  crazy.

running WC the boiler is in condensing mode all the time, until it heats the tank.

Edited March 12, 2022 by Beckside