[OpenTRV-dev] (no subject)

Tue Apr 2 13:43:29 BST 2013

Hi All,

Agreed on all points. To answer a few, I had looked at electronic TRVs but
had dismissed them as not really doing exactly what I want (why we're
here!), being a bit expensive to buy as an experiment and not being
capable of being controlled more intelligently (although it's interesting
to learn that the FHT8V is!). I figured that, lacking the mechanical
skills to make a motorised TRV head, using a little energy to save a lot
would be a reasonable approach for an initial toe-in-the-water, with low
cost as another advantage. It's something I'm still tempted to try while
hacking, because I can experiment with controlling a lot of radiators that
way with very little initial investment, but I agree that a motorised head
is the solution to focus our serious attention on.

Regarding integrating TRV and PIR, I guess physical location is the main
issue. I think of where my TRVs are positioned and most of them are
probably in the worst locations for a PIR! Has anyone looked into hacking
wireless burglar alarm sensors? These achieve decent battery consumption
and, as self-contained units, can be placed optimally. I guess they rely
on an "always on" receiver at the alarm box so might not be ideal for an
autonomous battery operated TRV but there might be the potential to learn
something from them nonetheless?

Regarding controlling boilers, I wonder if some of the resistance here is
perceived "complexity". Installing a TRV head is easy. You don't need to
be a plumber or electrician, so the resistance to purchase is low. Take it
out of the box, insert batteries, screw it onto your TRV and off you go.
As soon as you make a box that has to be hooked up to the boiler, it all
becomes a bit more of a liability. You call your electrician / plumber,
they haven't seen one before and so ensues the sucking through teeth.
That's probably why the mass market has avoided it. To get the best
benefits, though, I believe some control of the boiler is essential so we
have a challenge on our hands to try and make something that achieves
acceptance in this respect. It probably has to look, connect and, on face
value, behave exactly like a room thermostat / programmer yet be a bit
more intelligent under the skin!


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