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Improving central heating control

Posted: Fri Jul 26, 2019 1:08 pm
by ericmark
Part to save energy/money and part to ensure rooms don't over heat, I have started to fit more controls, however there are that many with such a huge price difference, and some will work with one thing, and others work with some thing else, I have found it a mine field. Take the thermostatic radiator valve (TRV) head.
EQ3TRV – programmable ‘on board’ with pushbuttons. £10
EQ3BTRV – programmable by smartphone using Bluetooth® or with push buttons. £15
i30 - The terrier i-temp is a Programmable Radiator Control (PRC) £18
Energenie - Links with Nest. Requires Hub. Works with IFTTT £73 per pair.
Danfoss Eco Smart - another bluetooth® £35
Honeywell EvoHome - think link to thermostat which is really a hub £61
Drayton Wiser - Requires Hub £40
Lowenergie eTRV Electronic Thermostatic Radiator Valve £23
Salus GP60
Tado £46
Lightwave TRV £55
JG Sheedfit Aura Wireless TRV £83
Then add to that some radiators don't control water flow, but control fan speed. Although the circulated hot air, be it direct or from a hot water supply is likely the best system, it is rather expensive, or needs to be built with the house not some thing easy to retro fit, and not convinced blowing air across cold walls and windows is good? See some advantages with hot and cool spots in the room. So looking at standard water filled radiators.

However the boiler must make a difference, some modulate, and those which do, can use return water temperature or connection to boiler ebus, with the latter this can seriously reduce the options. If the boiler will only work with a "Wave" thermostat (Bosch) then no point looking at other makes.

So to every radiator according to their need, and from every radiator according to their ability. So ideal is every TRV head controls their rooms temperature and tells the boiler (maybe vie a hub) if it needs hot water circulating. I think the EvoHome and Tado does this? However then factor in price and time for the conversion. So my house non modulating oil boiler and 15 radiators in 14 rooms with two wall thermostats, a cylinder for domestic hot water, two pumps, two motorised valves, over three levels.

So I took the Energenie from last house, so I have 4 of them, since they work with Nest, when I realised I needed a new thermostat I selected a Nest Gen 3 and since the TRV heads can follow Nest which is fitted in the hall, the hall and adjoining rooms have energenie heads. So I can set a schedule for all three areas, the toilet/shower room is very small so paying out £36.50 for another head does not seem worth it, however not sure about kitchen?

So jump to upstairs for a paragraph, what to stop over heating, and also heat only rooms in use, but since energenie does not send info back to boiler, they seem expensive so went for a lot cheaper unit, the EQ3BTRV got Bluetooth® version as some radiators hard to reach the TRV and even if reached hard to read the LCD panel, so £5 extra for Bluetooth worth it. However when they arrived I found they had some features not found on the more expensive energenie. One is it detects rapid drop in temperature and assumes this means a window is open, so shuts off for a selected time, this would be an advantage in the kitchen, where back door is left open when carrying in shopping.

As I compare the two there are a number of advantages with both.
1) Valve exercise fixed to Saturday 12:00 with EQ3BTRV but can select time and day with energenie when likely boiler not running.
2) EQ3BTRV has a press the dial boost where it opens valve to 80% for set time, energenie has a boost but fixed to 20°C and not long enough of fast enough to heat room in a hurry.
3) energenie reports room temperature, EQ3BTRV does not.
4) EQ3BTRV reports if valve travel outside limits so you know it's matched or not, energenie have to use chart to select spacer etc.
5) EQ3BTRV allows setting of offset, energenie has two sensors to compensate for heat from radiator.
6) Have to use tablet, phone or PC and needs a hub to set the energenie, the EQ3BTRV can be set on the actual device, but will only connect to one phone.
I am not talking about one being Bluetooth® so you need to be local and other wifi so you can alter around the world, as turning whole central heating on/off around the world really makes it unnecessary to adjust individual TRV heads, I am picking on the things you tend not to know about until after buying them. I like them both, they both have their place, however there are another 10 listed, all have some advantages and disadvantages.

I still have the flat to think about, 4 radiators all with TRV's and a simple wall thermostat no programmer, swapping latter for Nest E has been considered, so when we find we are getting visitors we can turn heating on remotely. As to TRV's at moment 6 still mechanical type, likely bathroom will have another EQ3BTRV as push a button for boost seems good, shower/toilet room likely stay as mechanical, flat bedroom, bathroom, kitchen and living room used that little may leave as mechanical.

I had originally intended to use terrier i-temp i30 but screwfix stopped stocking them, then found the EQ3BTRV which had Bluetooth® and cheaper. (Not from screfix they only do the EQ3TRV without Bluetooth®) as to which is best?

And that is whole idea of post, so people can add their TRV heads and say how well it has worked.

When I first fitted energenie I was not impressed, then I found it needed the lock shield valve setting, if too wide open whole radiator gets hot before valve starts to close so a high hysteresis, realised having valve on feed works better than return, and once lock shield set, reported temperature was the temperature set, however the geofencing was not really an option because of the anti-hysteresis software, and the valve as a result takes around 2 hours to get the last 2°C the first 8°C very quick, however house rarely cooled more than 4°C over night.