sink/bath immersion heater timer & wifi enabled switches

[Tiolll]

I have one of these:

And I am trying to find a switch that will allow:

- Switch to 'On' and 'Sink' for 1 hour (enough time to heat the water for sink and so that I don't need to remember to switch it off after)
- Switch to 'On' and 'Bath' for 2 hours (enough time to heat the water for the bath and so that I don't need to remember to switch it off after)
- Switch to 'On' only at night (so I can use my night electricity rates)

Nice to have features:

- Some way of telling if heating is still underway (so I know when there is enough water for a bath)
- Wi-Fi enabled so I can do all of this from my phone or better still Alexa

So such devices exist?

Thanks!

 

[Harry Bloomfield]

- Switch to 'On' and 'Sink' for 1 hour (enough time to heat the water for sink and so that I don't need to remember to switch it off after)
- Switch to 'On' and 'Bath' for 2 hours (enough time to heat the water for the bath and so that I don't need to remember to switch it off after)
- Switch to 'On' only at night (so I can use my night electricity rates)

Alexa and a Smart Plug can do that, but I would be wary of doing that with a basic SM, rated at 13amp.

- Some way of telling if heating is still underway (so I know when there is enough water for a bath)
- Wi-Fi enabled so I can do all of this from my phone or better still Alexa

You could have Alexa simply time it, and tell you when the time was up.

 

[oldbutnotdead]

Bit niche for off the shelf.
If you are up to a bit of fabrication, one of these
4 way wifi relay card, a couple of beefy relays (the ones on the card reckon they're rated to 13A but i wouldn't trust them) and the Ewelink app will work nicely.
One of the card modes is interlocked (so if channel 1 is active, channel 2 can't be), the app will do that 'switch off after x minutes' quite happily (you can define loads of different routines) and works well with Alexa.

 

[Tiolll]

Alexa and a Smart Plug can do that, but I would be wary of doing that with a basic SM, rated at 13amp.

Thanks, but I don't think Alexa and a Smart Plug can switch between 'Sink' and 'Bath' though right?

Bit niche for off the shelf.
If you are up to a bit of fabrication, one of these
4 way wifi relay card, a couple of beefy relays (the ones on the card reckon they're rated to 13A but i wouldn't trust them) and the Ewelink app will work nicely.
One of the card modes is interlocked (so if channel 1 is active, channel 2 can't be), the app will do that 'switch off after x minutes' quite happily (you can define loads of different routines) and works well with Alexa.

But wouldn't this need thermostat input so it knows whether to continue sending power to either bath or sink element? Or is this the on / off thermostat control not part of this unit and part of whats connected to the boiler?

 

[oldbutnotdead]

I don't Alexa and a Smart Plug can switch between 'Sink' and 'Bath' though right?



But wouldn't this need thermostat input so it knows whether to continue sending power to either bath or sink element? Or this the on / off thermostat control not part of this unit and part of whats connected to the boiler?

Unless the sink heater is an instant type (in which case there's no point controlling it) it and the immersion heater will have integral thermostats.
And missed the bit about temperature. Sonoff do a single channel module with temperature detection (but that would have to be at the tank). Or there are some really cheap Wifi thermometers on ebay that'll read up to 60°.

 

[Tiolll]

Unless the sink heater is an instant type (in which case there's no point controlling it) it and the immersion heater will have integral thermostats.
And missed the bit about temperature. Sonoff do a single channel module with temperature detection (but that would have to be at the tank). Or there are some really cheap Wifi thermometers on ebay that'll read up to 60°.

Sounds like the thermostat is built into the immersion heater, so no need to mess with thermostats. Rather than me tinkering with 4 way Wi-Fi relay card by adding relays (which seems intimidating), do you know of any wi fi enabled 2 way switches that could take the large ammount of power, so I could simply add in a basic on / off siwtch followed by a 2 way switch so I could say to 'alexa, turn on emersion heater for 2 hours and switch to bath for 2 hours'. Due to the high ammount of power involved in this I am a bit nervous of burning my house down!

 

[Harry Bloomfield]

Thanks, but I don't think Alexa and a Smart Plug can switch between 'Sink' and 'Bath' though right?

No, Alexa could do that.

But wouldn't this need thermostat input so it knows whether to continue sending power to either bath or sink element? Or is this the on / off thermostat control not part of this unit and part of whats connected to the boiler?

No the stat would have overall control, to be able to switch off. Nothing to stop you adding temperature sensing to the Alexa routine, to let you know the temperature and maybe switch off earlier than the stat switches off.

 

[oldbutnotdead]

Rather than me tinkering with 4 way Wi-Fi relay card by adding relays (which seems intimidating), do you know of any wi fi enabled 2 way switches that could take the large ammount of power, so I could simply add in a basic on / off siwtch followed by a 2 way switch so I could say to 'alexa, turn on emersion heater for 2 hours and switch to bath for 2 hours'. Due to the high ammount of power involved in this I am a bit nervous of burning my house down!

Short answer -no. I wouldn't trust any of the Wifi modules i've met with more than 5 amps- that includes Smart Plugs.
If you are intimidated by the thought of wiring a relay on the load side of another relay then best abandon your scheme now (or pay me or someone like me to build you a module).

 

[Tiolll]

Short answer -no. I wouldn't trust any of the Wifi modules i've met with more than 5 amps- that includes Smart Plugs.
If you are intimidated by the thought of wiring a relay on the load side of another relay then best abandon your scheme now (or pay me or someone like me to build you a module).

Ok, thanks. So if I decide to go down the wi fi controlled route I should get someone to custom build me something. If I wanted to go down the manual go press a button route, are there any manual button pressy boxes that I can press a button to turn on the bath emersion for say 2 hours? I am aware of basic timer on / off boxes like this, though if I can get one with this feature it would be nice:

 

[flameport]

And I am trying to find a switch that will allow:

- Switch to 'On' and 'Sink' for 1 hour (enough time to heat the water for sink and so that I don't need to remember to switch it off after)
- Switch to 'On' and 'Bath' for 2 hours (enough time to heat the water for the bath and so that I don't need to remember to switch it off after)
- Switch to 'On' only at night (so I can use my night electricity rates)

You are making this far too complex for nothing achieved.
The concept of those 'bath/sink' switches predates E7 and cheap overnight electricity, and have no real use today.

If you have cheap overnight electricity, then connect the lower 'bath' element to the off peak supply, or if that supply isn't separately switched by the electricity supplier, install a timer so that it's on at the cheap rate times.
The cylinder will be heated overnight at cheap rate, the thermostat in the heater will switch it off when it gets to temperature.
Unless the cylinder is tiny or you use vast amounts of hot water, that should provide most or all of the hot water at a cheap rate.

For the other 'sink' element, get one of these or similar: https://www.tlc-direct.co.uk/Products/SMSTBT4.html
which would be used to switch the upper element on for a certain time if required, and then switch it off. If it gets to temperature before then, the thermostat in it will switch off.

If the cylinder is old and has thin orange foam or no insulation at all, then get one of these: https://www.screwfix.com/p/cj4218bssf-four-panel-hot-water-cylinder-jacket-42-x-18-/43483 to insulate it.
If the pipes from the cylinder are not insulated, then get some insulation for those as well, as the pipes will have significant heat loss.

 

[Tiolll]

You are making this far too complex for nothing achieved.
The concept of those 'bath/sink' switches predates E7 and cheap overnight electricity, and have no real use today.

If you have cheap overnight electricity, then connect the lower 'bath' element to the off peak supply, or if that supply isn't separately switched by the electricity supplier, install a timer so that it's on at the cheap rate times.
The cylinder will be heated overnight at cheap rate, the thermostat in the heater will switch it off when it gets to temperature.
Unless the cylinder is tiny or you use vast amounts of hot water, that should provide most or all of the hot water at a cheap rate.

For the other 'sink' element, get one of these or similar: https://www.tlc-direct.co.uk/Products/SMSTBT4.html
which would be used to switch the upper element on for a certain time if required, and then switch it off. If it gets to temperature before then, the thermostat in it will switch off.

If the cylinder is old and has thin orange foam or no insulation at all, then get one of these: https://www.screwfix.com/p/cj4218bssf-four-panel-hot-water-cylinder-jacket-42-x-18-/43483 to insulate it.
If the pipes from the cylinder are not insulated, then get some insulation for those as well, as the pipes will have significant heat loss.

Amazing thanks, whilst I appreciate the help on getting this setup with WiFi from the other guys, even if I get a professional to make me one I think I would always be a bit concerned it might be a fire hazard.

So what you suggest sounds like the way to go. The cheap electricity doesn't come from a separate supply so I think it will be as simple as connecting the 'Bath' element to a timer and the 'Sink' element to a boost box.

2 questions come to mind before I undertake this:

- Using this setup will remove the switch that only allows one element to be on at a time. Am I right in thinking I shouldn't have any concern of what happens if the Bath and Sink elements are on at the same time, since the thermostats will just disable each of them? So this settup if perfectly safe in this regard?

- It would be nice to also have a Boost option for the 'Bath' element, do timers with boost ability exist? If so it might make sense to just install one of these for each element then I have a lot of flexibility.

Also thanks a load for the suggestion of the insulation jacket, the tank has a thin layer of orange foam just like you say

 

[EFLImpudence]

- It would be nice to also have a Boost option for the 'Bath' element, do timers with boost ability exist? If so it might make sense to just install one of these for each element then I have a lot of flexibility.

There is no point. It is the same water being heated whichever you choose.

The 'bath' and 'sink' labels merely relate to the amount of heated water needed.

 

[Tiolll]

There is no point. It is the same water being heated whichever you choose.

The 'bath' and 'sink' labels merely relate to the amount of heated water needed.

Agreed, though they heat different volumes of water which is what I would like to achieve whether through the timer, or through boost

 

[EFLImpudence]

Agreed, though they heat different volumes of water which is what I would like to achieve whether through the timer, or through boost

As I said, there is no point.

The 'sink boost' boosts the 'bath' as well; it is the same water.

 

[oldbutnotdead]

Agreed, though they heat different volumes of water which is what I would like to achieve whether through the timer, or through boost

Ahh, there was me thinking there were 2 separate appliances on the end of that changeover rather than 2 imm heaters in 1 cylinder.
If you improve the insulation on the cylinder you'll retain more energy