Heating control in Italy

Hi all,

In Italy, almost all flats/houses have this setup:



It takes "methan" in and uses to heat water to supply heater/radiator with hot water.

Acqua calda = hot water
Acqua fredda = cold water

There is also a thermostat which is usually placed in another room, far from the boiler (in Italian, "caldaia").
I would like to bring it to Z-Wave, what shall I buy? The install will be made by a techician (I have no problem installing Fibaro modules and so on, but for heating I prefer someone else does it).
I thought about HRT4-ZW + ASR-ZW setup. but there are two versions, for heating and for hot water.
I understood that the Horstmann/Secure thermostat shall be placed where the current thermostat is, the controller is of course connected to the boiler/caldaia, am I right?

Thanks
Marco

Do you know how the electrics/control side works? Is it the same as UK (albeit different colours I guess)?


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What do you mean exactly?
I have a thermostat which you can configure with schedules (night/days) or you can trigger manually.
Thermostat is in another room where the boiler is located and it is wired to the boiler.

OK based on that diagram I think what you have is what we call in the UK as a combi boiler (see more about different types of boilers here). Combi boilers are the most typical installation for small houses/flats were basically you don't have a hot water tank and the hot water is heated "live" as needed. There are other things you can do to check you have a combi boiler:

1) Look for a hot water tank next to the boiler (although sometimes these can be placed in the loft or somewhere else). If you don't find one then you have a combi boiler.
2) Open a hot water tap, the boiler should "fire" instantly. Close the hot water tap, the boiler should shut off.
3) If you have a combi boiler the hot water flow will be considerably reduced if you open a second hot water tap. Note that water flow will normally reduce if you have two cold water taps open too, depending on your water pressure and the diameter of your mains water supply. But the 2 how water taps open should reduce much than 2 cold water taps open since the boiler tends to be the limiting factor.

If you have a combi boiler then the Horstmann/Secure HRT4-ZW + ASR-ZW combo is all you need. You don't need a separate relay for the hot water since combi boilers don't need them. Combi boilers basically turn on automatically when demand is switched on (i.e. when you open a hot water tap). So for combi boilers you just need a controller just for the central heating. The Horstmann/Secure hot water controls are used for system or regular boilers where the hot water is heated and stored in a hot water tank.

There a couple of different ways the Horstmann/Secure HRT4-ZW + ASR-ZW combo could be installed but it will mainly depend on whether the boiler has a programmer as well or you are installing (or have one already installed) a separate one. Here is a sample programmer that is commonly used in the UK although combi boilers then to have built-in ones that look like something like this. Programmers work by having fixed schedules where the heating system should be on and off. They then typically connect their output relay to a thermostat. The user then decides what temperature the thermostat should be set. Then for the central heating to be switch on both programmer and thermostat need to be on. In other words you programmer will need to be on a On schedule and the thermostat will need to be set to a temperature higher than the current detected temperature by the thermostat. If you look at the HRT4-ZW guide there is a sample diagram on page 7 showing the cabling with a combi boiler. But the cabling is very simple, the ASR-ZW is basically a switch relay. In fact you can actually use a Fibaro Switch Relay (and some people have done so in this forum) to switch your bolier on/off for central heating and hot water. I think the person that did it was just trying to save money since a double Fibaro Switch Relay is a lot cheaper than buying the Horstmann/Secure combo and the extra one for hot water. If you do have a programmer you could also wire it in parallel with the ASR-ZW receiver. I discussed that setup on this thread.

Last thing is that you need to be careful on how you sync the Horstmann/Secure HRT4-ZW + ASR-ZW combo. Do not follow the instructions on the device's guide on how to "pair" the receiver and the thermostat! If you do that you will end up with those devices being in their own separate Z-Wave network and you would then not be able to include them in the Z-Wave network managed by Indigo. What you need to do is to add both devices separately to Indigo and then set the group associations between the receiver and the thermostat. That way the receiver will see the signal from the wireless thermostat via a group association and turn on/off as needed. Here are some equivalent instructions for a Vera system which should help you to figure out what to do in Indigo. Then depending on whether you are using a separate or built-in programmer or not and whether you are using it on serial or parallel you may need to create schedules in Indigo to decide when the heating should be on. If don't have a programmer then your Indigo schedules will simply set the thermostat "set" temperature to a low value (I use 12C) so that the heating is not normally working.

Thanks,
Christian

Another thing you need to be aware is that the Secure ASR-ZW Receiver has a Fail Safe mode that prevents the receiver staying ON if it loses contact with the Thermostat. The receiver can only enter Fail Safe mode when the receiver is On - it does not get activated when it is OFF. In normal operation the Secure Thermostat sends a signal to the receiver every 45-50 minutes. If the receiver does not receive this signal, it will go into Fail Safe mode after 60 minutes.

So if you have a schedule that changes the set temperature to say 22C so that the heating turns on, then that's fine. But if you turn the receiver On via a trigger then the receiver will enter Fail Safe mode after 60 minutes. If you want to keep the receiver on you have to keep sending On events from Indigo. One way to do this is to use "Delays" in the trigger. You can configure delays to repeatedly send 'on' throughout the duration of the Indigo schedule.

Hi,

thanks for the very detailed answer.
Yes, I have a "combi boiler", there is no reservoir for hot water, water is heated "on the fly".
I currently have a thermostat which I can use to set schedules and so on, located in the living room and then I suppose an actuator directly connected to the boiler.

The question is if I have to buy both thermostat and receiver/actuator or I can buy only the actuator and send other temperature sensor to read degrees and then use Indigo to send commands directly to actuator and not via thermostat; is this scenario possible?

Thanks
Marco

The question is if I have to buy both thermostat and receiver/actuator or I can buy only the actuator and send other temperature sensor to read degrees and then use Indigo to send commands directly to actuator and not via thermostat; is this scenario possible?

Yes this is entirely possible but I wouldn't recommend it. Firstly the price difference between the two options you mention is not much. In the UK this is £ 37 which is around € 50. The main advantage of having the thermostat is that you not only get a temperature reading in the room where you place the thermostat but also you get a display of the temperature you got your heating set to. If you manage the relay with schedules you will have no way of knowing what temperature you got your heating set to unless you look in Indigo. Also if your Indigo system is down your heating will be down as well as you will have no way of manually setting the heating temperature. You could still turn the heating on using the ASR-ZW Receiver manual on/off buttons but I would not consider this an acceptable way of using the heating as it will be constantly on (too hot) or off (too cold). The other advantage of using a proper heating thermostat is that is has been designed for that use. From the Secure manual:

"Thermostats using TPI (Time Proportional Integral) control algorithms will reduce the temperature swing that normally occurs when using traditional bellows or thermally operated thermostats. As a consequence, a TPI regulating thermostat will maintain the comfort level far more efficiently than any traditional thermostat"

So I think that should give you enough reasons to buy the thermostat. You can then use your Indigo schedules to change the thermostat's "Set" temperature to whatever desired temperature is applicable for time of day.

Ok, the idea was not to spare money, but just to know if it was possible

Then, I would not like to set the temperature using the thermostat, but I would like to use schedules/trigger in Indigo. How in this case work? Will Indigo send the command to thermostat or to the receiver?

Thanks
Marco

I am also thinking, as first step, to use a simple Fibaro Relay; in this case I will keep, as backup, the current thermostat and I will place the Fibaro Relay in parallel to the curren thermostat and I will wire it using the wires that go to the current actuator;
the question is if shall I put the Fibaro relay in place of the current actuator or put it "in parallel";
I think I shall link the new Fibaro Relay with the current thermostat, right?

Thanks
Marco

Marco, I response to this and your PM:

My fibaro relay is parallel to thermostat's receiver.

Thermostat is set at 5 permanently; if Indigo breaks, I can turn thermostat up and heating comes on.

Heating is controlled by scheduled script every 15 minutes.

First there's a tonne of schedules that set variable 'heatingscheduled' to true/false throughout the day.

Then every 15 minutes, IF heatingscheduled is true, and if (Any fibaro temp sensor) is < (Target Temp in each location), then turn on boiler relay. Otherwise turn off boiler relay. (ie heatingscheduled is false or sensors are all warm enough)

There is however an overrun variable that triggers whenever boiler relay changes, that turns true for 5 minutes then off again. This stops boiler toggling within 5 mins.

All instructions to turn on/off boiler check the variable first and either execute immediately or after 5 minutes delay.

I've a control page with a boost button that's also checked by the scheduled script.

Comprendez?


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How in this case work? Will Indigo send the command to thermostat or to the receiver?

You can send commands to either device but in most scenarios you will want to send commands to the thermostat only. Unless you do a more involved setup like the one howartp describes I see no benefit (aside from cost) in using a Fibaro relay to control your boiler. Also if you are going to use a relay only I would use the Secure ASR-ZW as it has manual controls as well and an LED indicating state, something you wouldn't get with a Fibaro and your Indigo system down. It will make servicing the boiler (which is required to be done yearly in the UK) much simpler, how are you going to explain to an Italian plumber how to switch the boiler on/off?

Using an existing thermostat makes no sense at all as you will not be able to control it with Indigo. The Secure HRT4-ZW is wireless and is battery operated so you can install it anywhere in your house with a simple screw on the wall.

I don't really get the point of yours questions. The traditional advice is start simple and add complexity as you go along. In that line the Secure HRT4-ZW + ASR-ZW combo is the best option. If you want to go full schedules and avoid the thermostat you can do so without issues.

Thanks to both for the answers.
Money is not the problem (I would not have started with HA... ), but I would like to find the simplest and cleanest solution.

You can see attached the wiring diagram of the current combi boiler;
TA1 is linked to the current thermostat and from what I see (I have no access to the boiler now as it is located in Italy and I am in Germany) it is not possible to remove it;
If I go for the Horstmann solution, shall I remove TA1 or put it in parallel to it?
I mean, then I have two thermostats and two actuators, right?
I suppose that TA1 has two wires going to thermostat and two wires (or something similar) going to the boiler, so I need also to put two more wires from Horstmann receiver to the boiler, right?

Thanks a lot
Marco

The simplest will be the Secure HRT4-ZW + ASR-ZW combo. I don't understand what you mean by this:

"I suppose that TA1 has two wires going to thermostat and two wires (or something similar) going to the boiler, so I need also to put two more wires from Horstmann receiver to the boiler, right?"

Why do you think you need two wires going to thermostat and two wires going to the boiler? The two wires you see in TA1 is all you need. In fact that diagram is the boiler, why do you think you need more wires to boiler? The diagram below implies that TA1 has a thermostat/actuator connected to it. It also implies that thermostat/actuator is either powered by 220v or battery powered. Either case the power of the thermostat is not shown. TA1 is a simple switch, that's why they show the bridge next to in case you want to have the boiler running constantly (like in the TA2 case). Boiler actuators work like a light switch, you have a live wire coming in and going out. The actuator simply interrupts the live wire when is off and bridges it when it's on. Simple. Most actuators will need two separate wires with 220v positive and neutral (L/N) to work. The Secure HRT4-ZW thermostat is wireless and battery operated so it needs no wires. The ASR-ZW receiver works with 220v mains supply. The ASR-ZW receiver will either use a live wire from the boiler, if the boiler provides one, or it can use the live mains used for the receiver by bridging the L connector and connector number 2. This is shown in the manual I linked.

Hi,

again a question about this topic.
Idea is to install a Danfoss Living LC-13 valve on each radiator, without doing anything in the central system (boiler, thermostat and so on).
That means, each room will have a temp sensor and valve on each radiator will react to temp changes (+ schedules, of course).

Will it work?

Thanks
Marco

No.