above below or equal

[Dave Fawthrop]

I am setting up my nice new Combi heating system. All radiators have TRVs except for the hall where I have a thermostat and no TRV, the doors to the hall are normally open, the radiator sizing is good having worked well for many years with the old boiler.

Should the thermostat be set above, below, or equal to the temperature the hall reaches normally?

[Roger Mills]

Equal - but you may need to throttle the hall radiator a bit with the lockshield valve to ensure that it doesn't heat up too quickly and turn the whole lot off before the TRVs have had a chance to operate.

Incidentally, assuming that the new boiler is a *condensing* combi, the radiator sizing may no longer be good - bearing in mind that, for optimum efficiency, condensing boilers need to run at lower flow and return temperatures than conventional boilers - thus reducing the *effective* capacity of each radiator.

[Dave Fawthrop]

|In an earlier contribution to this discussion, |Dave Fawthrop wrote: | |> I am setting up my nice new Combi heating system. |> All radiators have TRVs except for the hall where I have a thermostat |> and no TRV, the doors to the hall are normally open, the radiator |> sizing is good having worked well for many years with the old boiler. |>

|> Should the thermostat be set above, below, or equal to the |> temperature the hall reaches normally? | |Equal - but you may need to throttle the hall radiator a bit with the |lockshield valve to ensure that it doesn't heat up too quickly and turn the |whole lot off before the TRVs have had a chance to operate. | |Incidentally, assuming that the new boiler is a *condensing* combi, the |radiator sizing may no longer be good - bearing in mind that, for optimum |efficiency, condensing boilers need to run at lower flow and return |temperatures than conventional boilers - thus reducing the *effective* |capacity of each radiator.

The house has had its insulation improved since I did the heating calcs for the radiators.