Adding WiFi to immersion

macuser56

hi- we have an immersion hot water tank with a dual switch for on/off and sink/bath.

How easy would it be to add a WiFi module to this so we can set the on/off at night, or set it when on the way home (eg after sea swim)

I know the power of the immersion is probably say 3kw, and we can’t run this through a standard 13a plug (eg through a wifi controlled plug).

But I’ve seen manual time clocks (no -WiFi) on these tanks so what about a WiFi version, and how to wire it?

Cheers.

Sleeper12

There aren't too many smart timers suitable for an immersion. It has to be 16 Amps and most aren't. The one linked below will suit. I've never used it so don't know about it's quality

https://www.heatingcontrolsonline.co.uk/optimium-wifi-immersion-heater-timer.html

10-10-20

The right way to do this is by using what's called a electrical contactor (not contractor) and a device to drive it.

This Shelly supports a contactor:

https://www.shelly.com/en/products/shop/shelly-em-120a

And this is a contactor, for example:

https://www.eurosales.ie/products/ESC225.html?name=contactor&type=simple

macuser56

ok interesting- this was also something I was looking at:

https://www.amazon.de/gp/product/B0CF5N3YZ1/

could this replace e the fuse board switch, turning it into a WiFi controller Immersion (the immersion uses one board switch).

10-10-20

https://www.boards.ie/discussion/comment/122570143#Comment_122570143

No, absolutely not as it's not possible to physically isolate the circuit among other issues.

https://www.youtube.com/watch?v=dd16_Y9xfpw

macuser56

ok that’s useful thanks.

coylemj

OP, I have this timer installed for over 10 years and it does what you're looking for. It goes upstream of the Sink/Bath switch so you will still have to manually select Sink or Bath. My Sink element is rated 2 kW and the Bath element is rated 2.8 kW. You leave the Sink/Bath switch permanently switched 'On' and the timer controls the on/off cycles.

https://www.timeguard.com/products/wi-fi/wi-fi-switches/fstwifitu-wi-fi-controlled-fused-spur-tuya-edition

This is my setup, the mains feed goes first to the Timeguard timer on the right and there's a simple three-core (L/N/E) connection from the timer to the Sink/Bath switch. If your current Sink/Bath switch is very old and doesn't have an LED light showing it's receiving power, I'd recommend you swap it out for one that does. That will let you see when the timer is or is not sending power to the switch and allow you to diagnose the source of a fault. That's why the switch in the photo is new!