UFH - what electrics does UFH need - 2 setups.

[DJ_DIY]

Hi

I have an Grant oil boiler. Gravity fed HW. Single zone C-plan, no actuators, one pump, heating system. Two tanks in loft. immersion on first floor. HIVE hw/ch wireless controlled with receiver next to boiler. The wiring is very simple and all components are in the boiler cupboard in the middle of the house on the ground floor.

We have built an extension at the back of the house to extend the kitchen where we are having wet UFH. Haven't decided which company yet. The manifold will be fitted under the stairs which is accessed from the extension. The extension UFH has 3 zones.

Stage 1 - Replace the radiators in the old kitchen with UFH. this means the input to the UFH is the existing CH zone. Obvs we wont be able to have the UFH on without the house heating on.

Stage 2 - I've added 2 x 22mm pipes through the ceiling to the top of the boiler cupboard and down the walls of the extension which go under the stairs. At some stage in the future these pipes will be connected to the boiler in a 2 x S-type ch system. Unless we change boiler the HW will still be gravity fed I believe. To connect these pipes it's landing carpet up, floor boards up, holes through ceiling, and pipe work in boiler cupboard. Hoping i can leave this for a while.

Sorry if that was too detailed but my question is, what electrics do i need running from the boiler cupboard to the UFH manifold? I have a 13a supply fitted under the stairs. I need a floor probe for vinyl, so i can't use HIVE, which is a shame.

With the stage one set up could I have the UFH pump running whenever the house CH is on? If the house is at temp then the UFH pump is still running but wont cause any issues?

With stage 2 I need a 3 core and E cable as otherwise I wouldn't have control of the S-type UFH actuator to fire the boiler?

Thanks

 

[ericmark]

I have seen so many UFH systems, and each one seems to be slightly different. Once you have selected control method, often as a kit then one can talk about how to wire.

I need a floor probe for vinyl

In the main, only seen floor probes used with electric resistive UFH, electric chemical does not really need it, and water the whole of the circulation water is controlled to a temperature for the UFH basic idea is the water circulates all the time, and when it becomes too cool more hot water is added, this is why it uses its own pump.

The problem is there are two ways to heat a house, either as and when required, or 24/7. And I simply can't afford to heat all rooms 24/7, so for me UFH is a non-starter. The re-heat time to me is important, as I allow all rooms to cool overnight, and select which rooms to heat when. So dinning room finished with by 7 pm so heating goes off for example.

This was the whole idea of Hive, Wiser, Tado, EvoHome etc. The electronic TRV heads allowed one to control each room independently. And the major point was to be able to turn off heating when the room is heated from another source, like the sun, two days ago we had a nice day, and my desk thermometer read 27°C as the sun had heated the living room, heating had turned off for that room, but I had failed to close curtains in time. Summer the sun is higher, so does not cause such a problem, but I need heating in living room to respond fast, and UFH response time is too slow. It would be OK for North facing rooms, but not any rooms which get the sun.

So we look at heat pumps which run cooler, and we are tempered to fit UFH, but there is a reason why hypocaust stopped being used

we tend to forget it has all been tried before. The Italians can keep it. We just ask what did the Romans do for us. OK being a bit silly, but nows the time to think about it, not after it is fitted.

 

[DJ_DIY]

Well the floor has been levelled ready for UFH, and with the new extension/kitchen layout there aren't enough walls to hang radiators on to properly heat the room. It is North facing (unfortunately) .

As the builders didn't lay the concrete floor remotely level I had to add a few (42) bags of SL to bring it up to level. I asked for 34mm lower than FFL but the concrete went to 30mm lower. After self levelling I have 29mm to play with. I was looking at Wunda but with the height issue in mind I'm now looking at the Continal slimfix-18 and the Fastwarm 16mm DUO system.

So lets say I go with the Fastwarm. What do I need between the boiler cupboard and my manifold apart from two 22mm pipes !!

1mm cable

Cheers

 

[ericmark]

Plinth heater under the kitchen units. Fast heating as fan assisted, ideal for a room only used for an hour or so at a time.