Weather compensation what does it do?

[MNW67]

Interesting. Does the hall have more solar gain in the morning that the living room? If not, it sounds like your heating system is unbalanced i.e. too much heat in the hall and not enough in the living room. Where is the wall thermostat located?

 

[vulcancontinental]

Afraid I have no immediate solutions other than suggest you look for a control that fits into ErP control class 7

ClassVII
Weather compensator and room sensor, for use with on/off output heaters: A heater flow temperature control that varies the flow temperature of water leaving the heater dependent upon prevailing outside temperature and adjusts the compensation curve parallel displacement to improve room comfort. Heater flow temperature is varied by controlling the on/off operation of the heater. Package/system space heating uplift = 3.5%

Used to be the Honeywell QA6000 bt that's long discontinued. That type of control had an adjustable cycle rate. It worked very well, I still have it in my old, now son's, house.

 

[Andy165]

You say you have a Worcester oil boiler. Are the weather compensator controls branded worcester bosch ones ? Worcester boilers are only open therm with their own controls.

 

[ericmark]

Interesting. Does the hall have more solar gain in the morning that the living room? If not, it sounds like your heating system is unbalanced i.e. too much heat in the hall and not enough in the living room. Where is the wall thermostat located?

No hall has one small window in front door (never used) and the TRV set to 15ºC and at moment showing 18ºC so hall radiator has been off for most of the day, the wall thermostat however shows over 20ºC it seems heat comes from shower room, kitchen, and living room, plus likely through floor from flat below, the wall thermostat is likely at about the most central point in the house.

So living room not too bad today but the delay in heating living room and hysteresis have increased I suppose the point is without the TRV showing a history I would be unaware to what is happening, but the graph shows it so well, I do think the radiators are too small, however looking into changing wood framed double glazing to plastic double glazing with larger space between the two bits of glass, so will wait and see what that does.

You say you have a Worcester oil boiler. Are the weather compensator controls branded worcester bosch ones ? Worcester boilers are only open therm with their own controls.

I have no weather compensator, I was emulating what I was told they do, as far as I am aware oil boilers don't modulate, so OpenTherm is a non starter with an oil boiler, late mothers gas Worcester Bosch did modulate and with the same Energenie TRV heads it was spot on controlling the room temperatures, but trying to do same in this house has not worked, I have considered a second thermostat in parallel in living room, but when I change from a stepped increase of 0.5 ºC every two hours to jumping straight to 20ºC it seemed to improve. So I delayed.

Then I realised the 0.5 ºC every two hours worked better on warm days, and straight to 20ºC on cold days, so interested in the idea of weather compensation. @vulcancontinental suggestion had me look up "ErP control class 7" and that is what I tried to emulate with no success.

My whole idea when the electronic TRV heads worked so well in mothers house was to use them linked to the Nest Gen 3 wall thermostat, but one it works wrong way around, the wall thermostat sets the TRV's, and two it didn't work anyway, and I was loathed to pay out on another 'Smart' thermostat when Nest proved to be so useless. I tried using the auto set up, that was waste of time, and also the geofencing all that did was cause a few very cold days at beginning of last year when EE mast went down, and it thought I was not home, problem was every time I walked past it the build in PIR detected me, so it was not until second day before I realised what had happened.

So all the 'Smart' features now turned off. But once bitten twice shy, so I am doing my research first, seems likely either Hive or Wiser will be answer, Hive it seems needs a zigbee hub, I have one already, but not sure if it needs to be a special Hive one? Wiser a little more expensive, but if a need a hub then breaks out nearly even. It needs to be a wireless head, as don't have a UPS supply in Living room, but do have the UPS in the flat where the base would go.

Yesterday for first time tested, had a smart meter installed and central heating continued to work throughout the install.

 

[ericmark]

Second day with boiler output temperature turned down, putting is simple, with boiler temperature turned down rooms do not heat up as required, so will turn boiler back up.

 

[DP]

Weather compensation achieves something similar in a different way. It varies the boiler flow temperature depending on the outside temperature. So, you get gentler heating when it is warmer outside.

More to do with greater heat recovery from hot flue gases
Water returning to boiler will cooler when outside is milder so efficiency will be higher