Wireless Mains Switch on CH Timer

Sparky54 · 2 Dec 2018

Hi,

I recently bought a couple of WiFi mains switch boxes which just connect live and neutral from the input across to output when operated. One will be used to control our porch light and I would like to control the house CH with the other one, if that's possible. A bit of a Hive-on-the-cheap!

We have a Lifestyle LP522 timer with independant water and central heating. Would it be possible to connect the WiFi switch box lives across the CH NC and NO contacts on the back of the LP522, effectively shorting the NO contact to mains live when operated but leaving mains live still connected to the NC contact (with neutral also connected to the box input to power it)?

Any advice gratefully received. Thanks.

stem · 3 Dec 2018

The only possible problem I see with what you suggest, is that the power to the WiFi switch will be turned off every time the LP522 turns the heating on, and then back on when the heating goes off. Whether this will effect / harm it or not, I don't know.

Therefore, I would be inclined to keep the WiFi switch permanently powered by connecting its live input to the LP522 (L) terminal, and the Live output to LP522 terminal (4) ch on.

As you say, a neutral supply from he LP522 (N) terminal will also be required.

Sparky54 · 3 Dec 2018

Ah, yes... Thanks. I was reading the LP522 switch/relay contacts diagram as though they were external. So connect the WiFi switch input to the timer live / neutral for its power and the switch live output to CH NO to control the boiler/pump/valve. Can I confirm having live still connected through the timer to CH NC isn't an issue when the external WiFi switch has operated please?

stem · 3 Dec 2018

Sparky54 said:
Can I confirm having live still connected through the timer to CH NC isn't an issue when the external WiFi switch has operated please?

It is highly unlikely that there will be anything presently connected to the NC terminal (Aka CH off terminal 2) anyway. 99.99% of systems don't use it. It will just be a vacant terminal. And if there were it wouldn't matter it will never be electrically connected to CH on (4) where the WiFi switch is connected anyway.

Sparky54 · 13 Dec 2018

Quick update. Cheap (Amazon) Sonoff WiFi switch in and working well on the CH. Thanks for your advice stem. As you said, pin 2 was vacant.

Second switch is now working the external Xmas lights, so we can switch 'em on when it's getting dark and we're out! That will be moved to the porch light in the New Year.