I have a number of zones in my house which I am looking to control via standard central heating programmers. Since they will be located in the utility room, I am keen to enable the current status to be overriden by a switch/ button somewhere in the zone (e.g if the upstairs heating is off and it gets a bit chilly, they can hit the botton upstairs rather than coming downstairs). The reason for keeping them all centrally is to enable us to put all zones on without needing to go to each area.
Does anyone know of a control that allows the override button to be connected externally? I thought I saw a post from someone who had done this on this group but despite searching, I can't seem to find it.
I've built my own, which is part of a whole home automation system. The 'remote' extends to phone/Internet access from outside the house, not just controls inside the house, and it also takes into account occupancy (actually more so than timed control most people use today). I started nearly 10 years ago, although it's been modified and enhanced a few times over that period.
If you'd asked me 10 years ago, I would have guessed this would be bog standard by now, but in reality, heating controls commonly in use are unchanged, although some more elaborate ones are available.
Presumably the over-ride button would turn the appropriate zone on until the programmer's next scheduled OFF event?
If you can't find anything to do exactly that, you may be able to DIY a solution which turns it on for (say) one hour - by using something akin to the sort of staircase light switch used in some blocks of flats, which turns the lights on when you press it and turns them off again after a set time. I don't know whether any such switches are capable of being set to a time long enough to be useful for CH purposes, but there are other timing devices - like bathroom fan over-run timers - which may possibly do the job.
That would be my favorite solution. I looked at something similar for one of the local community halls to provide a simple "Press for heat" button. Plenty of options of off the shelf DIN rail devices with suitable delays and non-retriggerable ones as well. ie once triggered it ran for it's time period then off and could not be retriggered by pressing the button again turing it's run time or for a given period after.
Another solution is hacking into the programmer and extending wire from across the boost switch in the device. Might have problems with long wires and interference causing false triggering mind.
Two wires for a button (three if you want feedback that the button push has been registered) or the whole bundle for the power, button and switched output back to the central point...
Dave Liquorice coughed up some electrons that declared:
4 wire control flex or one triple+E: Live, Switched Live, Neutral (some battery powered electronic programmers don't need this) and Earth? This of course assums you no longer need a remote button because the programmer is now in the zone.
Or with Heatmiser network low voltage devices, one bit of STP/FTP shielded network cable, which carries +12V, OV, switched output and two for RS485 which allows a central control box, eg in the hall, or a PC to be linked in (I've seen documentation on the protocol lying around the web). Disadvantage is the relay in those can only manage ELV, so you need another relay to mains back at the boiler.
I'm doing mine differently to the official method with a bit of 5 core looped round and drops to each zone:
+12V, 0V for power to Heatmiser
-12V to wax thermal actuators (rad valves, which are 24V devices, actually fed with -12V common and switched +12V=24V) Switched +12V for UFH demand Switched +12V for radiator demand.
Each room will have a small junction box carrying the loop cable and drops to each zone's stat and rad/ufh valve. In same box, a diode will OR the local demand signal onto either the ufh or rad demand wires. Back at base, the two demand wires will drive logic interface relays to the respective pumps. Seems neater than a star topology and a big fat wiring centre.
He said he wanted to be able to over-ride each zone from a point *within* the zone - but he *also* wanted to be able to control *all* zones from a central point.
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