Advice on a heating set-up

Hi,
I am thinking of automating my heating, but I'm not sure what I will need.

My current set-up is combi boiler running 6 radiators, no thermostat just the temperature dial on the boiler. I am using the 24hr clock on the boiler and constantly either turning the boiler temp dial up or down, or the existing TRVs on individual radiators.

Can I fit something like the Z-Wave Eurotronic Comet Heating Thermostat to the radiators and use that to control the temperature? If I fitted these I am assuming it will just be like me manually turning my existing TRV's down so that the boiler shuts off? Or do I need thermostats that communicate with the z-wave TRVs and the boiler?

Thanks in advance for any advice.

Tony

Hi Tony,

I'm not sure if I'm getting how the boiler is turned on for heating, today.

You have a timer that is on the boiler itself. And a temp dial, on the boiler.

I'm assuming the following happens:
If the timer says 'heating on' and a radiator TRV is fully open, then heat will go to that radiator.

What happens if the timer switches to heat on, but all the TRVs are set low/off? Does the boiler still fire up?

Sam.

Hi,
no, if the timer says on but all the TRVs are off the boiler does nothing.

Tony

Ok,
so I don't know much about my central heating system. I tested it last night and if I turn the boiler on via the timer an then turn all the TRVs down, the boiler carries on happily pumping hot water round the system. I'm assuming this means I will need to wire in some kind of control into the boiler that connects to a thermostat or temperature sensor?

You would need something, an electrical switch, that controls the heating being on. Normally that is a room thermostat that is wired in. What is the make and model of the boiler?

It's a Baxi Duo-Tec combi 28 HE

According to the installation manual this can be controlled by external controls (which is as expected really.)

It accepts power for external controls (timers, thermostats, anything else that is basically a type of switch) from the same fused spur that the boiler is actually on. The actual control signal comes from, and back to, the boiler connectors.

Here is where it gets tricky. All the connections above are standard UK mains 230VAC that will allow 3Amps before a fuse blows.

If none of that worries you, don't touch it.
If that worries you, don't touch it
If that worries you, but you know exactly why, then I will not need to explain what to do next and you can skim what I'm about to write for the products.

Step 1:
I would strongly suggest you get a plumber in to fit an external control, a room thermostat would be best. They can then wire it in and your control of heating would be through this. Then turn all of your TRVs to max and leave them there. This step is not related to home automation or Indigo at all.
This would mean that your heating would come on with the timer but only remain on while the thermostat is set above the temperature it is sensing. This would depend on where the plumber had installed the thermostat of course. It will mean the heating only comes on when the air temperature around your new thermostat drops below the setting and not all the time when the timer is on, no matter what the TRVs are asking for, as you have now.

Step 2:
Replace the above thermostat with a Z-Wave switch. For example: http://www.vesternet.com/z-wave-horstma ... ceiver-hrt (in the UK)
You could go straight to step two here, skipping step one, but it still needs to be wired into your boiler and the mains power as per step one.
At this point you will simply have a switch that can activate your heating via Z-Wave , which means Indigo can control your heating.
Of course, you will need sensors for Indigo to control that heating, and the sky is the limit here. You can use Z-Wave temp sensors, mutli-sensors or, of course, Z-Wave TRVs. You can set your own timers, schedules, have heating control pages, what ever you want.

Step 3:

Add radiators Z-Wave valves, outside temp gauges, light sensors, presence .... whatever you want to feed into 'do I want heating on or not'. Use all these sensors, some triggers in Indigo, maybe an Indigo Schedule to set up logic as to when to turn your new Z-Wave boiler switch to on or off.

A few things to note here:

In the UK, it is 230 volt and up to 3-5 AMP. I'm mentioning this again as it can happily kill you.
Your existing temperature control on the boiler is likely to be controlling the maximum water temp (used for heating, not hot water), rather that room temp. Generally keep this at 60 degrees or lower (C). Looking at the manual there are no temp numbers, so half way.
Why the Horstmann unit than, say, a simple switch for the boiler control?
* They are plumber friendly, i.e. they are easy for a plumber to wire up. Be ready to get into conversations about Z-Wave though.
* They have interlock. That means if the unit stops receiving a regular signal from something else, it turns off. This is a good thing, as it means you heating will not then run all the time if your Indigo platform (as is, the Mac) fails for some reason. It does mean you have to keep communication going with the unit. I have my heating requirements all through Indigo variables and a regular 'ping' to the Horstmann (every five minutes) if my Indigo heating 'on' variable is set.
* It has normal push button on/off controls on the unit. Indigo/Mac failed, you have messed something up? You can still walk to the unit and hit 'on'.

Sam.

That is fantastically useful, thank you very much.

Tony