Temperature Settings

[FrankTrent]

I have a vaillant Ecotec 18 pumped open vent Y Plan with room stat and cylinder stat.
The room Stat is in the lounge. Is this ideal or should it be in the hall ? (I hardly ever use the lounge fire).
All rads have thermostatic valves. Should I replace the lounge valves with non-thermostat valves as I've heard that the room with the stat should not have TRV's.
What is a reasonable temperature setting. At present the boiler is set at 75 and the tank at 70.
Is it better to just set the boiler at maximum (75) all the time and avoid any messing around ? Won't this just mean that it will reach the thermostat settings quicker or is it better to run it a bit lower (but over say 65 so I've got enough hot water).

 

[stem]

The roomstat in the lounge is fine if you don't use the lounge fire which will affect it. Historically thermostats were located in the hall to avoid the effects of other heating sources such as fires, sunlight and cooking. Also the hall was often the last place to get warrm and so didn't turn the rest of radiators off too early.

Your comment about not having a roomstat and a TRV in the same room is correct. You cannot successfully have two thermostats trying to control the temperature in the same room. If you don't want to remove the lounge TRV, turn it to "max" or remove the head. This will prevent the TRV turning the radiator off allowing the roomstat to do it.

Regarding the boiler temperature settings, you are correct, the final hot water temperature in the cylinder is controlled by the cylinder thermostat, so increasing the boiler temperature will heat it more quickly, but not increase the final temperature. 65 is a common setting for hot water, infact some shower pumps stipulate this as a maximum. Of course the boiler needs to be set higher than the cylinder thermostat, otherwise it would never turn it off and would cycle continuously.

For better economy, condensing boilers usually work more efficiently at lower temperatures. Your Vailliant usually indicate recomended settings.

 

[FrankTrent]

Thanks
I will set the tank at 65. as the thermostat is about 1/3 up, I assume the water at the top where it is drawn off will actually be slightly hotter. I will set the boiler at 70.
As for the TVR's, the heating engineer just installed them when re-piping the system. I think his idea was that I could move the room stat around the house until I found a suitable position and then open the TRV's fully in that room (which is the lounge). I think that if opened to max it is about 28 so they will never activate. At least this will save me having to remove and replace with ordinary valves set 'fully open'.