I seem to remember he did not follow convention of that time where he lived. He had a lot of new ideas, and tried with quite a large success to change things.
The central heating in my mothers house is the second complete system fitted and neither did what they should have done, the second system was not done on the cheap, the whole of the original system was ripped out, and the professionals fitted a whole new system, removing the hard wired thermostat in the hall and replacing it with a wireless one, and replacing the thermo-syphon domestic hot water with a condensate-combi-boiler, the only bit of old system left was the power shower, I had to call them back as it was illegal to have a power shower pumping direct from the supply without heater tanks. I did note there are two bi-pass valves one built into boiler and one external but nothing really wrong with belt and braces.
Putting it simple the professionally fitted system did not work, there were some blatant faults, like every lock shield valve being wide open, as left by the professionals the front room was really cold, simply as hot water never got to the radiator, the thermostat in the hall had switched off the system well before the TRV's had closed enough to force water though that radiator.
So enter me, an electrician, not a plumber, and it was up to me to fix it, lock shield valves were first thing, soon got front room warm, however now we reach the technical bit, where I was out of my depth, forget upstairs that actually worked well once lock shield valves and TRV's we set, down stairs was the problem, and up stairs not used by mother, she only used down stairs.
The kitchen only has a towel rail, since cooking makes heat, not really a problem, wet room also towel rail, but also electric under floor heating, so in real terms just three areas to worry about, front room now converted to bedroom (also has a gas fire) living room (again also has a gas fire) and hall, the latter had a heavy curtain to stop heat going up stairs, and a threshold free front door for wheel chair access which is not well sealed.
The hall radiator is quite large for area heated, however since the front door lets in a draft specially when opened it does need a large radiator to reheat it after door is opened, and the hall radiator had no TRV and the thermostat was in the hall, which every professional I asked said was correct.
So the scenario was, wind direction, morning sun, and evening sun, would mean the three areas front room, living room and hall would go up and down in temperature like a Jo-jo. So I tried to cure the problems of morning sun making living room too hot, evening sun making front room (bedroom) too hot, and wind direction causing huge variations in temperature, after fitting seals on front door, it actually made it worse, next was programmable thermostat which could be carried room to room, this also a failure it would lose connection with base station in kitchen and rooms would either go very cold or very hot. So next idea was eTRV's in the two main rooms, also a failure, slight improvement but only slight.
The problem was getting the boiler to run, close the lock shield valve in hall so only just got radiator warm, and boiler would run, however open front door and hall freezing cold and it would take ages to re-heat, open the lock shield valve and radiator hot so hall also heated up quick, but then boiler switched off so other rooms were cold. I tried altering the lock shield valves in all three rooms, but all attempts were in vain, the room temperatures still went up and down like a Jo-jo.
So by now tearing my hair out, I tried what every one said should not be done, I fitted a TRV to the hall radiator, it took some setting so that the TRV turned the radiator off just before it got the hall warm enough to switch off the wall thermostat on a cold day, and opening the lock shield valve so hall radiator got hot quicker, but once set it did work, on warm days the thermostat on the wall does get warm enough to turn off the boiler, and on cold days it does not, so the TRV does all temperature control on cold days, the eTRV's are fitted so left in place, but really likely they could now be returned to standard TRV. But it works, not perfect, there is room for improvement, but it works, living room during day stays at 20°C to 22°C cooling to 18°C over night, and bedroom 22°C to 20°C morning and evening cooling during day and night to 18°C. The 20°C to 22°C is a bit more variation than I would like, would be better at 21°C to 22°C but it is near enough.
However although the rooms down stairs are now controlled, up stairs gets too hot over night, the hall now stays at a stable temperature, but it would be better if the hall could get cooler over night, however the hall TRV and wall thermostat are carefully balanced, I have set stops on the wall thermostat, so acts as a switch, turn it down to bottom stop and central heating is in de-frost mode, tune up to stop and hall stable at 18°C to 19°C, but alter the wall thermostat and TRV has to be trimmed to match.
So if I can fit a eTVR to the hall radiator and a nest or hive wall thermostat, they can be set to follow, so I can set temperature to drop over night. It is the next stage. It would seem I can set app to get Nest or Hive to turn on boiler if the current is lower than target, when I first looked the apps worked other way around, they set the TRV to match the wall thermostat, now you can get wall thermostat to be controlled by the eTRV instead. So it seems it could be done.
Your system will confuse the hell out of pretty much any tenant. For a rented property it needs to be simple and robust. Basic programmer, basic roomstat and manual TRVs. Anything else is just asking for trouble.
That is a fair point, so maybe not worth moving to next step, in fact, if I rent out the house, then better I remove the eTRV heads, and use the original standard ones. Unfortunately the eTRV will not really help in my house, the open plan means no TRV down stairs, they are only fitted up stairs, and the hard wired programmable thermostat works A1 and has done for years, may be son or daughters will use them.
