Electronic room thermostats

[Keyser Sose]

Guys, I have noticed that you can get programmable thermostats - what a great idea. However, do these get their power from the same wires as the existing "dumb" thermostat or do I have to run a power feed to it?

On another note I have a Potterton EP2002 central heating controller. However, I can't set different programmable times for Hot water and Central Heating - even though I have two valves in the tank space (instead of a 3 way valve -( why??)). If I get a new programmer,will I have to start fiddling with the wiring? Thanks, Steve

[The Natural Philosopher]

Yes, if you have live/switched live/ neutral and earth available. If no neutral you are in doggy doo..or use a radio linked battery one. No leads at all :-)

Yup. But it ain't that hard.

If the hot water tank is insulated consider running it 24x7 anyway. Or put a Big Red Switch somewhere to turn it on manually.

[Tony Bryer]

Non-wireless CM67s are battery powered: they just have two terminals, one either side of the switching relay,

[Mathew Newton]

Not true. Most (all?) battery powered stats don't require a neutral.

Mathew

[Michael Chare]

Have a look at the Danfoss TP9, This is a two channel programmer/thermostat.

It would replace youR existing programmer and room thermostat. Quite likely you would be able to use the existing wiring.

If you have a fully pumped system you can run the C/H and H/W separately

If you have a gravity H/W then depending on your configuration you may find that the C/H can only be on if the H/W is also on. Honeywell C-plan (or equivalent) provides independent control of H/W and C/H

-

Michael Chare

[Dave Plowman (News)]

Perhaps the majority are battery operated so only need two wires. There are mains ones, though.

I doubt many want different times.

Most makers have the circuit diagrams on their website.

[Christian McArdle]

Almost all are battery powered. You will need to look hard to find a mains one, although they do exist.

Christian.

[The Natural Philosopher]

Oh..I think I certaibly do. Peak water times are in the morning, and late evening here, plus a midday period sometimes.

In order to get fastest heating of teh CH., teh water comes on an hourt eralier in the mornoing, but the CH (UFH) comes on early afternoon..to allow for the slow warmup.

HW comes on at midday for an hour, and then MUCH later - around 9pm.

[meow2222]

theyre ok if they work, but with a sample size of 2 I've found them a right waste of time, not lasting long at all, and not worth having. Reliabilitys more important to me, so I've gone back to bimetal stats, which happily last many decades.

NT

[Christian McArdle]

I have a sample size of 5 and have never seen a failure. OTOH, I've never seen a bimetal stat that could hold a temperature better than +/- 3C or so. The programmable ones are good for 0.5C.

Christian.