There are two methods – here are their advantages and disadvantages:

METHOD A

This method requires 1 dual relay.

If you have a separate supply circuit for your heating and water signal you will need to use method B.

The programmer will be connected through the relay in such a way that the boiler will work as it always has – turning on and off when the programmer tells it to, but it can be overridden for one cycle. For example, the programmer tells the boiler to turn on – you then tell it to turn off. It will stay off for one cycle before turning on again. Likewise, if the boiler is off and you turn it on manually, it will stay on until the programmer would normally turn it off. In this method, if something happened to the Home Center, the boiler will still be controlled by the programmer but you would lose the manual override.

This method is less flexible, but requires very little extra programming and is robust in the event that your Home Center 2 was ever stolen or struck by lightning.

The programmer will now control the boiler as it always has but you can override it by manually switching the relay on or off. You can write scenes to do the same.

METHOD B

This method requires 2 dual relays.

If you have a separate supply circuit for your heating and water signal you will need to use this method.

The programmer will be connected through the relay in such a way that programmer is simply an input to the Fibaro System. The boiler will be controlled by the Home Center 2 and will turn on and off when the Home Center 2 tells it to. In normal mode, if the programmer tells the Home Center 2 to turn on or off the boiler, it will, but it can be overridden manually for one cycle or for longer periods.

In this method, if something happened to the Home Center 2, the boiler would not turn on as it relies on the logic on the Home Center 2 to turn on and off.

This method is very flexible, but requires much more programming and requires the Home Center 2 to be present for heating and water to work.

The programmer will now turn the ‘input’ relays on and off and you will need to write a scene (or 2 [or more]) to control the output relays when you want them to turn on and off.

There are two methods shown in this tutorial.

For Method A, you will need 1 x Fibaro Dual Relay (2 x 1.5kW) Module.

For Method B, you will need 2 x Fibaro Dual Relay (2 x 1.5kW) Modules.

METHOD A

The procedure for method A is as follows:

• Click here for Method A – boiler control wiring diagram.
• Leave the existing heating programmer as it is.
• Identify if there is room inside the box with all the wires going into it for one dual relay. If there is no room, add another box above or besides it.
• Take the wire that is coming from the programmer which goes live when there is a call for heat and disconnect it from where it was and connect it to O1 of the relay.
• Connect the S1 of the relay to where the wire was previously connected.
• Do the same for the wire which is in control of water, but use terminals O2 and S2 on the relay.
• Connect the permanent live to the L terminal on the relay and loop it across to terminal I as well. This will provide the power for the outputs of the relay.
• Connect the neutral to the N terminal.

METHOD B

The procedure for method B is as follows:

• Click here for Method B – boiler control wiring diagram.
• Leave the existing heating programmer as it is.
• Identify if there is room inside the box with all the wires going into it for two dual relays – one will be for the water and one will be for the heat. If there is no room, add another box above or besides it.
• Take the wire that is coming from the programmer which goes live when there is a call for heat and disconnect it from where it was and connect it to O1 of the relay.
• Connect the S2 of the relay to where the wire was previously connected.
• With another relay, do the same for the wire which is in control of water. Use the same terminal numbers.
• Connect the permanent live to the L terminals on both relays and loop it across to the I terminals as well. This will provide the power for the outputs of the relays.
• Connect the neutral to the N terminals on both relays.

• Include the relay(s) into the Home Center 2 and give them names and put them in a room.
• You need to change parameter 13 to the second option (ON = switch contacts connected …)

If you don’t change parameter 13, if you override the boiler and turn it on, then when the thermostat changes state, it will turn the boiler off (toggling its state). With parameter 13 set, when the thermostat says to turn on, the relay will turn on – regardless of if it was already on.

For information on saving energy with Fibaro, see our tutorial Five Easy Ways to Save Energy with Fibaro.