Horstmann Programmable Room Stat

Thats not normal behaviour for the types I've seen. Its usually low batteries = no heating. Surely the opposite would not be good idea?

In article , John writes

The relays in these are latching (magnetically assisted I think) and so if the batt fails when on demand then it won't have the oooomph to reset the relay.

The Horstmann looks like a pattern match for a Tower one I have as a temp solution and I don't hold that one in high regard.

Yeah. I bought one of those, but never fitted it in the end. It sticks out of the wall too much, looks a bit cheap and I couldn't work out how to manual override the thing. (I'd lost the instructions).

Christian.

I've got one of these and it does fail in the "demand" mode. I'm going to fix my old regular thermostat in line with it at a slightly higher temp just in case.

In article , Christian McArdle writes

If you're still interested, you override by pressing one of the arrow keys until the displayed demand temp blinks once, then use arrow keys to set desired override temp. Resets on next program step - easy huh ;-)

Btw, thanks for the Sunvic recommendation, could be a suitable stop gap for me.

They don't have a conventional relay but some form of 'motorized' switch - this is needed to save battery consumption. Hence the loud - and annoying

- noise when it operates rather than the relaxing click of a relay. So I'd guess it might fail in either mode when the batteries die.

At the risk of sounding like you know who (and whatever he's just been reading about...)

I still recommend the Centaur Stat 7 - less than 30 quid.

Screwfix part 12517 (iIRC).

Even these controls are too complex for about half the customers.

Sounds good, but it's huuuuuuuuuuuuuge. It's 12157 btw.