Room thermostat recommendation

[Cursitor Doom]

Hi all,

I've decided it's time to fit a room thermostat to my central heating for
a bit of improved control, but I've no idea which type is compatible with
my boiler, which to give it its full title is a:
Worcester Greenstar Heatslave 18/25 oil-fired condensing combi job.
Preferably something well-proven and ubiquitous that I can find no
problem sourcing and fitting, cheers.

cD.

[Roger Mills]

Does the boiler's installation manual specify the type of stat required?
[I suppose it might just specify a WB model rather than a generic
description].

In any event, I don't think you can go far wrong with any programmable
digital stat with volt-free contacts.
--
Cheers,
Roger
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[John Rumm]

On 16/11/2013 17:23, Roger Mills wrote:
> On 16/11/2013 14:40, Cursitor Doom wrote:
>> Hi all,
>>
>> I've decided it's time to fit a room thermostat to my central heating for
>> a bit of improved control, but I've no idea which type is compatible with
>> my boiler, which to give it its full title is a:
>> Worcester Greenstar Heatslave 18/25 oil-fired condensing combi job.
>> Preferably something well-proven and ubiquitous that I can find no
>> problem sourcing and fitting, cheers.
>>
>> cD.
>
> Does the boiler's installation manual specify the type of stat required?
> [I suppose it might just specify a WB model rather than a generic
> description].
>
> In any event, I don't think you can go far wrong with any programmable
> digital stat with volt-free contacts.

I quite like the Centaurstat 7 (screwfix), a 7 day prog stat - needs 4
AA bats that last for years (literally)

--
Cheers,

John.

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[Michael Chare]

On 16/11/2013 14:40, Cursitor Doom wrote:

I suggest that you study the installation guide for the boiler.
Hopefully this will give you a clue as to how you might connect a room
stat. If you don't have a copy you may be able to get one from the
manufacturer's web site.

The other issue to decide is where you are going to site the thermostat
and its sensor (if separate) and whether you are prepared to lay cables
to the boiler or want a wireless and probably battery dependant solution.

Ideally you should also check that the contact rating of the thermostat
is adequate for you boiler.

I am a fan of programmable thermostats, and I would suggest that you
look at the Honeywell range for starters. It looks like you can even get
ones that connect a wifi network.




--
Michael Chare

[bm]

Yep, positioning is crucial to gas bills. Our stat started off in the
hall, forget it. Place the stat where you'll be, most of the time. Out
of 10 rads we only ever use 5. 2 in toilets, 2 in living room (with
stat), 1 in kitchen. Leccy blanket for bedroom, gorgeous, and gas is
still too expensive. I suggested housebricks and an open fire in the
living room gradually burning the garden, wifey wasn't impressed.

[Cursitor Doom]

Thanks for the tips, chaps, all very welcome.
I should just point out that I did read through all the bumpf that came
with the boiler but nowhere can I find any reference to specs for
thermostats!
Would be fun to get one that could be programmed hour-by-hour by a
Raspberry Pi for an optimal solution. I've already programmed a Pi to act
as an embedded controller for a timelock device I built to stop me
necking back too much red wine. :)

[fred]

In article <l6adi9$ksb$1...@dont-email.me>, Cursitor Doom
<c...@notterriblyvalid.org> writes

You don't say what kind of pile you have, modern with low thermal mass
or old with high thermal mass.

You also have oil which I understand is not a boiler you want cycling
unnecessarily (although you say it is a combi which blows that theory
out).

If you have a high thermal mass home then I'd suggest a stat that offers
at least the option of simple on-off control as this means you can have
long slow burns (to suit oil fired) and the high thermal mass smoothes
out the temperature bumps. Dave Liquorice on here has a home like this
and I think he uses a Danfoss TP7000-RF which I understand he is pleased
with and it has the programmable option of simple on-off control or 2
proportional modes which cycle the boiler multiple times per hour.

If it is a low thermal mass house you may be better with a proportional
control, these fire the boiler multiple times per hour to keep the temp
smooth (programmable, the minimum, 3 recommended for oil) but be aware
that even when you are out and set a setback temperature of say 16 or
18degC, a proportional controller will still fire the boiler 3 times per
hour to maintain it at a pointless 15.9-16.1degrees. Same in summer if
you have a setback temp set or if you go on holiday, pointless cycling
<end rant>. Honeywell are the king on these sorts of controls (eg CM927
wireless, CM907 wired), v easy to use and set up but they only do
proportional (cycling) so if you find you don't like that then tough you
are stuck with it. With the Danfoss, perhaps not quite so intuitive to
set up but you can choose the operating mode.

--
fred
it's a ba-na-na . . . .

[Michael Chare]

On 17/11/2013 12:41, Cursitor Doom wrote:
> Thanks for the tips, chaps, all very welcome.
> I should just point out that I did read through all the bumpf that came
> with the boiler but nowhere can I find any reference to specs for
> thermostats!

I doubt that you will find much in the way of specs. I would expect with
a combi boiler that the installation instructions would tell you were a
room thermostat should be connected, and the implications of any
existing programmer if there is one.

I expect many thermostats will work. You just want one with volt free
contacts, and able to switch the current that you boiler takes.

> Would be fun to get one that could be programmed hour-by-hour by a
> Raspberry Pi for an optimal solution. I've already programmed a Pi to act
> as an embedded controller for a timelock device I built to stop me
> necking back too much red wine. :)
>

No reason at all for not using a Raspberry Pi. You can attach relays and
1-wire temperature sensors to them.


--
Michael Chare

[chris French]

In message <l6adi9$ksb$1...@dont-email.me>, Cursitor Doom
<c...@notterriblyvalid.org> writes

Have a look at the Heatmiser wifi ones, they publish the protocol and
there open source projects for controlling/reading them.

<http://www.heatmiser.com/index.php/thermostats/wifi-thermostat-series>
<http://code.google.com/p/heatmiser-wifi/>


--
Chris French

[Roger Mills]

On 17/11/2013 12:41, Cursitor Doom wrote:

> Thanks for the tips, chaps, all very welcome.
> I should just point out that I did read through all the bumpf that came
> with the boiler but nowhere can I find any reference to specs for
> thermostats!

No, but it's not going to require anything too exotic. If you look at
pages 30 - 32 of the installation manual (if it's the same one that I
downloaded) you'll see where an external stat has to be connected. The
diagram shows a mechanical on/off stat with an accelerator
heater/resistor, so ignore the neutral connection to that if you're
using a digital stat.

> Would be fun to get one that could be programmed hour-by-hour by a
> Raspberry Pi for an optimal solution. I've already programmed a Pi to act
> as an embedded controller for a timelock device I built to stop me
> necking back too much red wine. :)
>

I'm sure you *could* do that, but you'd have to do a fair bit of
programming if you wanted to mimic things like proportional control and
optimum start - not to mention party or holiday mode - built into stats
made by the likes of Honeywell.