Settings for underfloor heating

maynooth_rules

Hi, we have purchased a house with underfloor heating. Despite being here 3 months, we are still clueless how to work it. We have rads upstairs. When we turn in underfloor heating it also heats the rads upstairs to a warmish temperature. We are at the point where we want to install rads downstairs as we just aren't getting benefits from UFH. Any help would be very appreciated.

Dardania

How many thermostats do you have?
And how many timers?
Can you take a photo of these?

With rads, it’s normal to turn them on when you need them, and turn off later.

Whereas with underfloor, it gives out its heat far slower so you tend to leave it operating longer. So the perfect situation is to set it to be on to whatever your desired temp (e.g. 20C) whenever you are downstairs, and leave it do it’s thing rather than switch it on and off.
And at night, if your controls allow it, you should leave it on but to a Lower temp (say 17C) so that in the morning it can boost back to comfort easily enough.

maynooth_rules

Dardania

Wow that’s a pretty old school looking device. BUt it appears relatively sophisticated. These things are meant to be just setup, and left to run - the boiler is called in when needed automatically with those.
I can’t see the model number on top to find a data sheet or manual, but let’s give it a go as to how it most likely should work...

First off, make sure the clock is set, and the clock runs. That’s a moving part, and if it can’t keep time you’re snookered from the off (and will need to find another solution)

Then set the dozens of pins in the clock according to daytime or nighttime. It appears if they’re pushed out from the centre, it’s daytime, and in to the centre it’s night time.
Once you do this it’s possible to set a desired space temperature for day or night, and the heating system will control to that temp if it’s day or night.
You can consider, if everyday the house is empty, to schedule a few hours after people leave to work or school that it should be treated as night time, for energy saving. And also you should have the day time temperatures set for an hour or so before you actually need day time (day everyone arrives home at 5pm, set daytime starting at 4pm)

Then set your day and night temperatures using the dials to the right.
I suggest maybe 17 for night time, and maybe 19 or so for daytime. Perhaps a bit more for daytime depending upon personal preference.

For your hot water temperate that’s showing very low. It should be 60C to prevent legionnaires.

And then set the mode using the dial to the right. I suggest setting to the timer position (one click clockwise from where you are now) so that it follows the time settings you’ve programmed.
The other symbols, from most anti clockwise, working clockwise appear to be:
Off
Just heat the hot water to the temperature set (so a summer mode)
Heat the space using underfloor to night temperature setting, and presumably heat the hot water too
Heat the space to day temperature and presumably the hot water is heated too
Run the program according to timer
Switch everything on, don’t care about any temperature feedback

The other dial with the fractions appears to be a control parameter which you shouldn’t touch - I’d say that’s a time constant setting or some control transfer function parameter - basically saying how long the controller should wait for the space to heat up after switching on the boiler.

Patience is the name of the game with setting this up - I’d say run it for a day then see what it’s like tomorrow before making small changes only, otherwise it’ll be hard for you to finetune, and understand the reaction to your changes of settings.
And also be cognisant there are other components most likely somewhere out there like temperature sensors in the space, in the hot water cylinder and possibly some motorised valves - you should check that they exists and if possible they work (especially the motorised valves) and are not blocked (especially the temp sensors)

If any of those temp sensor components are missing or broken, it might be worthwhile looking into getting say a nest fitted - much simpler and can guide you better.

And presumably the standalone time clock to the left is for the upstairs rads only? You said that when you switch on the underfloor it heats the roads upstairs - that might suggest the zone valve for the upstairs rads is locked open.

maynooth_rules

Thanks a million Dardania, very much appreciated. You have made something thats quite difficult a bit easier for me
I see the SEAI do a grant for heating controls upgrade (€700). would that be something I should consider?
Clock works fine thankfully. Just havent got to a sitation where I would even class downstairs as 'warm' from the underfloor heating.



Yep the clock on left is rads upstairs.
Would a nest work with both underfloor and rads?

Rows Grower

Do you not have individual heat controls in different rooms / zones as well?

Dardania

Nest would work with both underfloor and rads. Note you'd need two nests - one to do the downstairs + water heating, and one to do upstairs.

The SEAI grant could be very helpful for you here, however it might be difficult to find someone to fit it for you. 2 possibilities:
- Nest have a list of registered professionals on their website (who may or may not be qualified to achieve the SEAI grant)
- Go to someone like Electric Ireland, who do installation offers, and deal with SEAI on your behalf (see https://shop.electricireland.ie/products/install-detail/nest-thermostat )

It might be easier to go the Electric Ireland route - they'll replace like with like (so won't touch things like valves etc.) however I have a gut feeling that you don't really need to look at those items - the problem is the controller.

With respect to whether you're warm enough or not - I would suggest try do what I have in my post above, and leave it a few days. Don't try to overcontrol it - just let the system take over. Pateience is key when getting these systems going.
If it's still not satisfactory, you might have another issue that needs diagnosing (like:
1. what is the temperature setting on the boiler - it should be around 70C
2. there should be a "mixing valve" somewhere, that has 3 pipes and a dial. It is meant to reduce the boiler water temperature down to around 40C or so for the underfloor circuit. Is it working - what's it's output temperature - does it feel reasonable for walking on in bare feet?
3. When was last time the boiler was serviced - maybe during the summer see if you can get it serviced, when the plumbers are quiet. Again, energy utilties are very good for arranging this on your behalf
)