Heating Controls for New Build with UFH

[BMD]

Hi,

I am looking for some advice regarding heating controls for a new two storey build with UFH. The house is 290 sq ft. All rooms have south and north facing windows with the kitchen and living room having a lot of south facing glass.

I was thinking about having four zones downstairs based on usage;

1. Living room, kitchen and utility room
2. Reception room
3. Office
4. Hall and downstairs toilet

Upstairs I was thinking of 4 zones;

1. Master bedroom (ensuite)
2. Two small bedrooms and bathroom
3. Guest bedroom (ensuite)
4. Hall

or should I be putting programmable thermostats in every room and effectively have 14 zones?

My heating system will be a combination of solar, OFB and solid fuel stove (with back boiler) linked up to a 300l three coil copper cylinder.


I would be grateful for any advice on this with respect to thermostats, controls, water etc. as this is an area I know little about.

 

[kfpg]

I was advised to put stats in every room.
Having ignored the advice I recently spent money to upgrade and am now almost at the stage where all rooms have their own stat.
I should have done so from the start which would have been cheaper in the long run.
If you can afford it I would advise to do this now.

From experience I found that the dynamic of every room is different and therefore rooms on the same zone rarely all need heat or no heat at the same time. Rooms have different external wall orientation, different size windows with different orientations (changing solar gain) and different floor coverings and finally different occupations.

 

[Shane007]

I was thinking about having four zones downstairs based on usage;

1. Living room, kitchen and utility room
2. Reception room
3. Office
4. Hall and downstairs toilet

Upstairs I was thinking of 4 zones;

1. Master bedroom (ensuite)
2. Two small bedrooms and bathroom
3. Guest bedroom (ensuite)
4. Hall

or should I be putting programmable thermostats in every room and effectively have 14 zones?

This will not create 14 zones. Think of each manifold as 1 zone and not each room. You will have 3 zones, 1 downstairs, 1 upstairs and 1 for domestic hot water.

With UFH, each room MUST have it's own thermostat. You can have bathrooms, halls, very high ceiling areas, as open circuits without a stat. When a room with a stat calls heat, it will also heat the open circuit area, however, try to restrict this as much as possible. En suites are normally installed with an actuator controlled by the bedroom thermostat.

The most important part of the installation is that it is designed correctly and then it is strictly installed to that design specification. It is extremely expensive to correct an ill-installed UFH system. Ensure design flow rates are adhered to and make sure to install a modulating circulating pump such as a Grundfos Alpha2. This will help to maintain the flow rate required no matter how many circuits are open/closed. Also make sure floor insulation is turned up around the perimeter of each room to stop heat loss through sides. This is significant in UFH.

Also inform the UFH designer of the proposed floor covering for each room. This will have an effect on the flow temperature requirement and subsequently on the floor surface temperature requirement.

I would not bother with programmable stats, as they are over complicated to use and easier to control with timeclock/control centre. Standard wheel type are fine. Most UFH manufacturers will have their own types that co-incide with their manifold actuators. On no account install an UFH system without manifold actuators. I have seen this with disastrous effects, i.e. 6 fills of oil per year!

 

[villa 1]

Another very important part of the installation will be the correct fitting of the solid fuel stove. This heating source will have to be correctly installed by a contractor who is familiar with open vented heating systems, especially if it is to be linked up to two other heating sources.
An incorrectly installed open system will play havoc with your heating system, especially UFH.

 

[Shane007]

If you are connecting solid fuel to UFH, then you can only do this through a buffer tank. UFH always works best as a pressurized system, albeit it can work open vented. If they meet at the buffer, then through the use of coils, one could be open vented and the other could be pressurized, i.e. indirect buffer tank. Would not be my fitst choice though.