I have one of these, I put it on the slowest to heat/furthest sink. I put a 200uF capacitor on the trigger wires and plugged it in to a smart outlet. I added an automation in homeassistant to turn that outlet off after 3min whenever it gets cycled on. Whenever we need hot water we just toggle the button in HA and the showers all have hot water in <90s and <1L.
I have one of these, I put it on the slowest to heat/furthest sink. I put a 200uF capacitor on the trigger wires and plugged it in to a smart outlet. I added an automation in homeassistant to turn that outlet off after 3min whenever it gets cycled on. Whenever we need hot water we just toggle the button in HA and the showers all have hot water in <90s and <1L.