[OpenTRV-interest] Programmable TRV performance

[Mark Wigmore]

Thanks Damon, I was thinking it might be a combination of factors as you
suggest.

Looks like the best thing would be to have a TRV controlled by a wireless
sensor in another part of the room.

Cheers,

Mark

On 16 February 2015 at 15:49, Damon Hart-Davis <EMAIL ADDRESS HIDDEN> wrote:

> Hi,
>
> It may start closing well before the target temperature to try to minimise
> fluctuations; I start closing about 1C below the target I have in the
> OpenTRV control loop.
>
> Also it may see some direct radiative heating as I sometimes do on OpenTRV
> units, and be reacting to that.  It’s still something I’m working on
> handling fully elegantly.
>
> There may also be a calibration error of +/- 1C on the temeprature sensor
> (the one we use are closer than that).
>
> In other words, that place may be approaching 20C including direct
> radiative heat and air rising from the flow/return pipe when the valve
> closes thinking that it’s hit 21C.
>
> Rgds
>
> Damon
>
> > On 16 Feb 2015, at 14:52, Mark Wigmore <EMAIL ADDRESS HIDDEN> wrote:
> >
> > Hi,
> >
> > Sorry if this is a bit OT, but I thought people in this forum might be
> the most likely to know the answer.
> >
> > I have a Honeywell HR25 programmable thermostat on my bedroom radiator.
> It is programmed for 21degC in the mornings, but I can hear the valve start
> closing from about 17.5deg as the room warms up and completely closed by
> 19deg room temperature. There's a good airgap all round the TRV; 500mm to
> the bed, 300mm gap under the bed, and 600mm at the end of the bed nearest
> the TRV. There is a window 240mm above the rad and the curtain stops 170
> above.
> >
> > Any idea what's going on?
> >
> > Regards,
> >
> > Mark
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