[OpenTRV-dev] TRV control - my problem, and musings so far

Tue Apr 2 11:45:13 BST 2013



A couple of points (in-line)
> 1) Defeat unwanted zones on a time basis.
> I've yet to test this theory, but I reckon a small heat source attached to
> a TRV will cause it to close, or at least reduce the set temperature
> significantly enough to be useful. The TRV4 has a large metal bulb as its'
> sensing element, meaning that a resistor could be coupled with it quite
> easily and very, very cheaply to apply a little heat. Feed this from a
> timeswitch and we have a cheap and easy if crude solution to, for example,
> avoid heating the lounge in the morning when it will not be used until the
> evening. How to achieve this with a good WAF might need further study!

> 2) Control zones using an in-room "smart" device
> Pretty much what's proposed here. I came across the Eberle TS 5.11 in
> Conrad. It's a thermoelectric replacement TRV head operated by mains power
> (although I believe lower voltage variants are around). Each room would
> have temperature and occupancy detection and a heating schedule, with
> set-back or "comfort" temperatures selected accordingly. I have mains
> power near every radiator I want to control, so energy use of the head is
> not an issue. I'd mused on intercepting the burglar alarm PIR circuits to
> glean occupancy information. Obviously OK on a one-off basis but not
> likely to appeal for a "consumer" product!

This approach whilst valid, has the drawback that you need to power the resistor for all the time you want the zone disabled.

For this reason our focus is very much on TRV replacements that have a motor to drive the pin within the valve head.

Take a look at my blog for an example of such a unit (which I've then disassembled)


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