I have a plain old switch, and I fancy a timer to take advantage of cheap leccy.
Is this going to be a drop-in replacement for a simple switch?
https://www.screwfix.com/p/lap-tmihdig-digital-immersion-timer/1804r
Looks like it.
I just wired our immersion into a plug and stuck a socket next to it, so I can use any old mains plug timer etc.
Caveat: IANAE but worked in plumbing & heating merchants for 14 years until 2020.
I don't think that's a swap for what your switch as chances are the switch will be a fuse spur. You may need something like this instead if you want a straight swap.
The one you link to would be wired in next to your existing switch.
https://www.screwfix.com/p/greenbrook-t205-scr-digital-7-day-fused-timer-spur-switch/7643G
While it might seem like a DIY job, I'd be getting in someone who didn't need to ask an MTB forum whether it was the right thing to put in...
I did exactly that with the very switch Northernmatt linked to. Easy to do.
I just wired our immersion into a plug and stuck a socket next to it, so I can use any old mains plug timer etc.
My considered advice is that you should step away from the electrical jobs and pay a professional to do it properly.
A lot of mains plugs will get alarmingly hot with 3kw load running for any period of time. You want to guarantee your any old mains timer is happy on 13A? Melty melty sparky fire risk. Probably in a nice dry airing cupboard with lots of combustible things in it too.
As an only slightly related question, have you done any plumbing or gas work in your house?
To answer the OP, yes it will do that job. however, LAP stuff is absolute gash, get one from a more reliable brand.
A lot of mains plugs will get alarmingly hot with 3kw load running for any period of time.
No worse than any other 13A load...
You want to guarantee your any old mains timer is happy on 13A?
No, just use any old 13A rated timer....
As an only slightly related question, have you done any plumbing or gas work in your house?
Yep completely rewired and replumbed it inc moving all the gas pipes. Still here 20 odd years later.
Not good practice to have a constant 13a load on a socket or even a ring
New builds have to have their own immersion circuit from the consumer unit with their own MCB
That timer linked is fit for purpose, just loop the flex out of the wall from your fused connection unit or switch into the timer then out to the heater.
It will get way hotter than most loads it is not suitable to put through a plug and socket. I can’t think of anything that uses a plug drawing that sort of current continuously for anything up to 4 hours maybe more.
I’d also get a timer rated at 16 amps as I’ve found the 13 amp rated ones don’t last.
I can’t think of anything that uses a plug drawing that sort of current continuously for anything up to 4 hours maybe more.
13A heater? I use a couple in the workshop over winter to heat it up.
4H is pretty long, our tank is a 'pencil' one, probably less than an hour to heat via immersion, although can't recall the last time we used it, it's only a back up in case the boiler dies and it takes me a few days to source parts.
My preference these days would be for a smart relay (Shelly 1, 16A) wired in to your existing switch. Cheaper, easier to fit, easier to program, more functional.
While it might seem like a DIY job, I’d be getting in someone who didn’t need to ask an MTB forum whether it was the right thing to put in…
You should be worried if I weren't researching from all angles and making absolutely sure I was doing the right thing. It may be an MTB forum but there are electricians on here, whom I was hoping would comment ...
