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First winter using the (gas) underfloor heating in our kitchen living room. On the ground floor. It's a solid floor, so it takes a long time to heat up and cool down.
The (cheap) controller/thermostat I have is rubbish and simply switches the heat off when too hot and on when too cold. That means the temperature massively overshoots what's needed - reaching a max of 23.5 when set to 20.5 today. I've set it to be on constantly (instead of off at night) and that's not helped.
So what can I get? As well as doing a better job of controlling the temperature, I'd quite like to be easy to program, maybe over wifi from a PC or phone.
The rest of the house has a separate timer and thermostat (and TRVs) and is fine.
Try Heatmiser
The reviews on Amazon for the Heatmiser PRT-TS WiFi suggest it's no better than my current one at controlling the temperature.
Maybe I should get one of these anyway, and then code up some software to monitor the temperature and turn it on and off using its HTTP interface.
It needs a separate programmable room stat so that it can come on independant if the other heating, PROVIDING it has been connected into the heating system correctly.
If not it will never work properly because of the lag times with it compared to your other radiators.
Honeywell stuff works well, with the nicer versions even learning your system so they know when to switch the system on according to the temp outside and the time to heat up. However without knowing exactly how your system is wired it is difficult to know if they would work but I had one before and would recommend it (a wireless model)
It needs a separate programmable room stat so that it can come on independant if the other heating
Yep - it's got that.
It's a wired combined timer and thermostat; on the wall in the room with the UFH. I've just had a look inside, and it has two wires, one of which is 240V live (connected to 'CON') and one currently non-live (connected to 'NO'). There's a third unused connection labelled 'NC'. The cable goes off to a junction box where it joins the cable from the main heating & H/W timer; and I assumed heads up to the boiler in the attic.
I'll have a look at some Honeywell ones.
Con = common, no = normally open contact, nc = normally closed contact
The Honeywell ones are also nice because they don't just go on/off but rather go into a sort of pulse width control when they get close to the right temp ie. they go on for a bit and then off for a bit. You will need to check the model though to make sure it does it. Sorry but I can't remember the model number of the one I had but it worked incredible well.
However, for underfloor you might also want to see if it has a setting for that as the lag with underfloor is huge and will give any control system trouble.
Honeywell. Prog room stats will be fine. Just need to make sure it is timed to come on early enough to allow for floor to warm up. Also go off much earlier as floor will be giving heat out for a long time afterwards.
And remember to allow for a setback temperature.
Hmmm. So in terms of heating control I think I want TPI - so this page on Honeywell [url= http://www.honeywelluk.com/products/Programmable-Thermostats/TPI/ ]http://www.honeywelluk.com/products/Programmable-Thermostats/TPI/[/url]. That's a CM907 then. But I've just started watching this [url=
- and that's as hard to program as the current one. If I want to put the temperature up a bit I've got to re-program 5 time periods on 7 different days. It has a 'copy day' to help but that's still dreadful. I want to have two temperatures (day and night) that I specify in one place; and then set the times that it switches between them in another. Have I missed something on the Honeywell site? Any other options?
If I want to put the temperature up a bit I've got to re-program 5 time periods on 7 different days
That's not my memory of it at all. IIRC, if you put up the 19 deg temp for example then the same temp on all days moves up. However I don't have it any more so I can't guarantee that, sorry
If I want to put the temperature up a bit I've got to re-program 5 time periods on 7 different days.
I took a quick look and the 907 looks similar to what I had except the one I had was wireless. My memory is that if you used the up and down temp buttons that are to the right of the display then it changed the temp for all of the days without having to reprogram them all. However... there was occasions when it didn't do that but I never found out why. It also has the 'optimal start' feature where it works out what time to switch the heating on to have the temp correct at the time you want but that's a feature you have to switch on somewhere.
You want a CM907, they are pretty simple to program, you can still use them as a manual stat and not affect the built in program. There are options to turn some of the switchings off via an installer menu.
But I would leave them and step your temps up gradually.
Been told recently by an M&E engineer that with under floor heating in rooms with separate heat producing devices (bathrooms with heated towel rails, kitchens, any kit which can cause the temp in a space to fluctuate quickly etc) its helpful to have a secondary thermostat which monitors the floor temperature (usually accommodated under the floor finish). Its supposed to stop the system cycling on and off in a way which work for conventional radiators but isn't helpful for underfloor heating.
Can't comment on how well this works but may be worth considering