As an electrician I have found balancing radiators a problem, I am sure using a differential thermometer on the in and out pipes it is easy, but I have lost the sensors for my differential thermometer, so I would balance by turning the rad closest to boiler off, then crack open until one pipe got warm. And repeat slowly moving out from the boiler.
This seemed to work, until I came to my parents house, and I had a problem with rooms getting too hot, my problem is the TRV was marked *123456 what good is that? If I can set the TRV to 20ºC then I stand a chance, when only adjusting one thing, the lock shield valve, so I got a pair of electronic heads, now I could set to 20ºC and it actually reported to the PC,
this made it so much easier, if the current exceeds target close the lock shield a tad. I actually moved the pair radiator to radiator to set them, once set I only have one variable so the TRV can go back to mechanical type.
Clearly the wall thermostat needs turning right up while setting the radiators, can't set them if boiler turning on and off, and then once set the wall thermostat turned down to just above the sample room temperature on a cold day, so it would not turn off on a cold day, but would with a warm day.
And it worked, every radiator warm, only if heating turned off for a time, would radiators get hot, it did as designed and the rooms were maintained at the set temperatures without any over shooting, removed the hysteresis, and boiler would modulate as it is designed to do.
However, tried to repeat it here with an oil boiler, which does not modulate and it was a failure.
But in theroy even with all lock shield valves wide open, the system should if left running long enough sort its self out, as each room heats up, the TRV should close, and force water to the next room, the order the rooms heat up in may not be what you want, but unless some wall thermostat turns off the heating, then each room should heat up.
Biggest problem is on/off wall thermostats, turning the heating off to some room prematurely, the TRV is king, and the TRV should set room temperatures, but unless linked electronic, the TRV can turn boiler first down, and then start a mark/space ratio, but it can't turn it off, so we need the wall thermostat to turn off heating on warm days, on cold days it just stays on 24/7.
OK in real life it does not work quite that way, I at least want three temperatures, overnight maybe 17ºC, then in day 19ºC and evening 21ºC to do that both the TRV and wall thermostats need to be programmable, and for best results the TRV needs to link to the hub, with the Drayton Wiser and Honeywell EvoHome you don't need wall thermostats, the TRV's tell the hub what to do, I have not got to that stage yet, I however do have two thermostats in parallel one in hall, and one in living room, since living room has an open fire, having a thermostat in that room only would not work, but the hall cools too slow, so having one only in hall does not work either, so I use two. I will swap my unlinked programmable TRV heads for linked heads in the fullness of time, slowly moving to Wiser.
Be it the TRV or the wall thermostat, today most do report how the room temperature has responded, one does not care if radiator hot, cold, or warm, what one does care about is the room temperature, and how closely it follows your settings, so my living room thermostats show
at TRV and
at wall thermostat, as said oil heating so it does not modulate, if I look at living room temperatures now, above fire place 19ºC, wall thermostat, 19ºC, west TRV 19ºC and south TRV 18ºC this is actually unusual I thought I would be quoting very different temperatures through the room, I was going to point out how hard it is to get a room at an even temperature. Hall TRV 16ºC and wall thermostat 17.5ºC very rare to see them all so close.
The home is just over the point where boiler will kick in.
