Connect shelly i3 to shelly 1

Hello all,

i'm trying to connect a Shelly i3 to a Shelly 1 to be used in order to control the central gas heater of a floor heating system.

i3 is connected to the control central of the floor heating system and when it closes a contact the i3 should signal this to the shelly 1.

Shelly 1 is connected to the central gas heater(Immergas Victrix Tera) on the thermostat contacts.

Basically the shelly i3 and the shelly1 should mimic themselves, when i3 senses that it its input is closed is should sent this to shelly1 which also should close thus telling the central gas heater that hot water has to be sent to the floor system.

On the i3 i selected button type toggle switch and in the I/O URL action button switched on URL with http://192.168.0.129/relay/0?turn=toggle

This works to turn on the heating(shelly1 turns on by closing its contacts 0 and 1) but when the i3 should open the shelly1 this doesnt happen. What am I doing wrong?

Basically I am trying to replace the wires in the picture below(cut with red) with a wireless solution as the current cables are cut somewhere in the wall. Shelly1 is on the boiler, Shelly i3 is on this command central for the valves.

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SO to use both first and second actions here listed.

Thank you! Now it works.

Is it possible to define the power on default mode for shelly i3? after power loss the i3 sends a ON command to the shelly1.This in turn turns the central heating ON although the termostats didnt request this. In the i3 menu i couldnt find a default mode after power on like in the shelly 1.