Combined central heating programmer and froststat?

23 Jan 2003
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United Kingdom
Hi, is there such a thing? I currently have a wired programmer and no thermostat. The house will be vacant for a while and I want the heating to come on when the temperature drops. I know I could pay for a frost stat to be fitted, but could I do any of the following cheaper options?:

1. Replace the programmer with a combined unit using existing wiring?
2. Replace the Programmer with a froststat using exsisting wiring? (I could manage without a programmer when the house is vacant) as long as the heating kicks in when the temperature drops and I could drop the temperature on the froststat if I needed instant heating.
Advice appreciated.
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HI John, that's correct. Just a programmer/timer with 3 on/off options. It was no big deal when the property was occupied but it's a big deal now :(
HI John, that's correct. Just a programmer/timer with 3 on/off options. It was no big deal when the property was occupied but it's a big deal now :(
Fair enough - I guess that probably means that all the radiators have thermostatic valves?

If it's anything like a standard programmer, it should probably be a pretty trivial job to add a thermostat. It doesn't really need to be a "frostat" - regular room thermostats can usually be turned down to a very low temp., thereby achieving the same thing.

Kind Regards, John
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Most of the digital thermostats have a 'holiday mode'. This allows you to set a minumum temperature (usually the minimum is 7°C) and for normal temperature setting to recommence on your return from holiday.

eg Digistat 3 etc

I suggest you get a stat like that installed and then it can be used later to provide temperature control for the house occupied or empty.

If you want to go really modern, then some of teh fancy ones can be controlled over the WonderWeb, from your sun bed on Grand Cayman, eg!
Honeywell CM707 and CM907 have frost protection when set to off, they do run on batteries tho.
Warning I fitted the Horstmann HRFS1 programmable thermostat to my mothers central heating system, which reading the spec has the holiday function which should in theory at push of one button allow the temperature to fall can't remember the limit. And seems a really good unit.

However this unit can be used free standing and my mother started to move it about the house. This was when I realised it had a flaw, it does not hand shake, all it does is send a command heat on or heat off, and it assumes the receiver will get this command.

OK a little extreme my mother put it in a draw, when I arrived house was at 32°C same true in reverse, if out of range when set to 21°C the house can hit 12°C and still the heating had not cut in.

The cure was to wall mount, once fixed it seemed to work far better, however on changing the temperature set it can take 1/2 hour to respond. She also has the Honeywell Y6630D wireless thermostat installed, this is very different, on changing the temperature set, the response is near immediate. However like any wireless unit should the batteries become flat it will fail.

At home we swap the batteries every year, does not matter if still working we swap them anyway, they will normally last 2 years but don't want to be stuck hunting for batteries. It is an old version of the Horstmann DRT2 and my son and daughter also use the same unit, hard wired but still requires a battery. With good quality batteries they work well.

But a frost stat normally is hard wired and does not require batteries, once it has run for 6 months even the HRFS1 with new batteries will likely work A1. But to fit then leave is not really giving it a chance to show any problems.
Thanks for all your very helpful replies. I will research the units you mentioned. This is a great forum :)

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