No timer on HW/CH system?

[Graham.]

If the thermostat or programmer is hard wired and switching mains, surely it would be mains driven, and wouldn't need a battery other than for power fail backup?

[Graham.]

The ones that use a rotary encoder instead of up/down buttons are more intuitive to use. The set-point and the current room temperature should be displayed simultaneously.

[T i m]

Combi boiler in a flat with just a room stat in the lounge (from what I can see).

Can you get (at a reasonable cost) a simple Clock / timer stat for such circumstances and if so, would / could they be battery powered, assuming the stat isn't currently fed by mains?

Cheers, T i m

[spuorgelgoog]

Programmable thermostat. £29 + VAT

battery powered, contacts are changeover volt-free

Owain

[ARW]

And the timer for the HW? (sorry Tim I am politely taking the piss - no offence meant)

[alan_m]

An any modern electronic room stat provides timing. My controller box is configured to be on for CH 100% of the time and my room stat provides the timing with 4 off configurable on/off periods each with its own temperature for both on and off.

While mine is a wireless module with the receiver fitted to the location of my old "simple" thermostat the mains switching is achieved by use of a relay. I assume any battery run thermostat will have a relay for any mains voltage switching.

[alan_m]

Its a cpmbi boiler with hot water on demand?

[spuorgelgoog]

You had me there ... for about a second ...

Owain

[mm0fmf]

Better, they have a latching relay. So power is only drawn from the battery when turning the relay on or off. No power is needed to hold the relay in either state.

[John]

T i m [e-mail]> wrote in news:u3bbsetk0orskaor6bpurdf530ipbfee0a@

4ax.com:

/If you have programable temp control then you don't need a CH Timer. If you have a combi then you don't need a DHW timer.

[chrispvholmes]

I had a programmable thermostats timer from Maplins aeons ago.

Would I call it simple?

Not in terms of the kind of users I encounter in my day job!

[alan_m]

But I'll bet that they could program their video recorder/hard disk PVR to record their favourite soap episode or configure their mobile phone for social media.

[John]

and put a dog's nose of their selfies.

[T i m]

Excellent, thanks very much for that mate. It seems to tick all the right boxes. ;-)

I think it would be used in the 5+2 day mode as one occupant has the weekends off and the other two other days in the week (where it could just be overridden)?

Cheers, T i m

[T i m]

I think Adam was trying to be funny. I put HW/CH in the title because the boiler does both so I threw that in *in case* there was some special reason there wasn't a timer for the CH already.

Like a fridge needing the heat of an incandescent lamp or a boiler coming on on it's own to prevent freezing etc.

Cheers, T i m

[spuorgelgoog]

Mine's got LEDs :-)

Modern boilers will have a frost stat internally but if yours doesn't you can check the instructions for that prog stat to see if it does.

Owain

[tabbypurr]

you can get just stats & you can get programmable stats. Only the latter do timing. Beware of crap UIs.

NT

[spuorgelgoog]

Not always. Many modern ones are volt free contacts so there is no connection between the relay contacts and the internal gubbins, which are battery powered.

Means there is no requirement for a neutral at the stat location, just L and Call.

Owain

[alan_m]

Most of these electronic room thermostats cater for a variety of different configurations so may use battery for electronics and a mechanical relay for switching.

[ARW]

You are talking bollocks:-)