Immersion Heater Time Switch with battery backup...

[paulw0t]

I currently have a strange setup - Basically its economy 7 style with 10 hours a day off peak

The immersion heater was replaced with an external Willis type one which runs at 3KW and heats the water in about 30 minutes. As such left on at night rather than a trickle its blasting the water at the start and heating it all night which is far from ideal... The other option which is what we are doing is getting up eariler and switching it on (again not really what I want to do in the winter)

I was wondering if there is any time clocks that I could use that wouldn't lose the time when there is not power to the unit (the other 14 hours of the day) Does anyone know of any units like this ? Or would I have to take a live feed from somewhere else to keep the time clock running.

Thanks

 

[chivers67]

http://www.tlc-direct.co.uk/Main_Index/Timers_Index/Immersion_Heater_Timers/index.html

Any good to you?

 

[paulw0t]

Perfect looks just like what I'm looking for!

 

[JohnW2]

http://www.tlc-direct.co.uk/Main_Index/Timers_Index/Immersion_Heater_Timers/index.html Any good to you?

The (usually not user-replaceable) batteries in these things are really designed to cover occasional brief periods without power (e.g. during power cuts). Do you think the battery would last very long with a power duty cycle of 10 hours on/ 14 hours off every day? I just don't know, but it might be a bit of a concern for me.

Kind Regards, John

 

[chivers67]

What would you recommend then?

 

[JohnW2]

What would you recommend then?

Without getting more complicated**, I don't think there's anything else to recommend. The question is whether the battery will last long enough (with the OP's duty cycle) for the 'non-complicated' approach to be reasonable/sensible - and,as I said, I just don't know.

** As the OP sort-of suggested, the more complicated approach would be to run a timeswitch from the 24/7 supply and use its output to operate a relay/contactor to control the immersion.

Kind Regards, John

 

[JohnW2]

...an external Willis type one which runs at 3KW and heats the water in about 30 minutes. As such left on at night rather than a trickle its blasting the water at the start and heating it all night which is far from ideal...

Given the uncertainties (at least, in my mind) I've been discussing with chivers67 about how long the backup battery in a timeswitch would last with your sort of duty cycle, I wonder if you might perhaps reconsider your statement above, and perhaps decide that the timeswitch is not actually necessary ...

You may have overlooked the immersion's thermostat. If your hot water cylinder is reasonably well insulated, once the water has initially heated up to temperature (at the start of the cheap electricity period), it's thermostat will mean that it will actually be 'off' for most of the rest of the 10-hour period, merely coming on briefly from time to time to top up the water temperature if it falls. I therefore doubt whether there is any significant downside in allowing the immersion to be powered (but not 'on' for much of the time) for the whole 10 hours.

Kind Regards, John

 

[JohnW2]

duplicate deleted

 

[EFLImpudence]

No need to run an on-peak supply to the immersion heater - in our place we had a BX2000 unit installed next to the fuse board, and just ran a single cable to the immersion heater, with a DP 20amp switch next to the heater.

Excellent idea

 

[JohnW2]

No need to run an on-peak supply to the immersion heater - in our place we had a BX2000 unit installed next to the fuse board, and just ran a single cable to the immersion heater, with a DP 20amp switch next to the heater.

Excellent idea

Indeed it is, and I didn't know such animals existed (missed that other thread). However, if, as stated, the OP's only concern is that his immersion is 'on' for the entire 10 hour off-peak period then, per my most recent post, he probably does not actually need to do anything at all - the thermostat will do it for him.

Kind Regards, John

 

[EFLImpudence]

Yes, quite.

I fitted a timer last week to an 'ordinary' immersion (i.e. 24 hour supply) and the lady was perturbed because the neon in the switch was still on permanently.

I said I could take it out but "No, that'll be alright".

 

[JohnW2]

Yes, quite. I fitted a timer last week to an 'ordinary' immersion (i.e. 24 hour supply) and the lady was perturbed because the neon in the switch was still on permanently. I said I could take it out but "No, that'll be alright".

Indeed.

Having thought a bit more, I'm not sure I fully understand the point of (all of) this BX2000 thingy. If one has two separate 'supplies' (one 24/7 and the other off-peak only), it's clearly useful to have a facility to have a 'boost' from the 24/7 supply during peak periods if one wishes - but what's the point of it having a timer - and what does that timer actually do?

Kind Regards, John

 

[EFLImpudence]

Having thought a bit more, I'm not sure I fully understand the point of (all of) this BX2000 thingy. If one has two separate 'supplies' (one 24/7 and the other off-peak only), it's clearly useful to have a facility to have a 'boost' from the 24/7 supply during peak periods if one wishes - but what's the point of it having a timer - and what does that timer actually do?

That was just the relevant device in the other thread.

This OP needs a 24 hour supply for the clock.

I admit I would have thought about how to get the supply to the immersion until phatboy's post (which I hadn't thought of before).

 

[JohnW2]

That was just the relevant device in the other thread. This OP needs a 24 hour supply for the clock. I admit I would have thought about how to get the supply to the immersion until phatboy's post (which I hadn't thought of before).

Yes, I understand all that (and, as I've said, was also unaware of the BX2000, or anything quite like it). However, my question to you was about the BX2000 when used for it's intended purpose. It is designed to have two 'supplies' (one 24/7 and the other off-peak) and therefore can give boosts during non-off-peak periods, but why doies it need to have a timer in that situation (given that the off-peak supply is only there during off-peak times)?

Kind Regards, John

 

[EFLImpudence]

The BX2000 doesn't have a clock.

It just facilitates changing two supplies to one immersion - just a change-over switch.

It also allows the two supplies to two immersions - not sure what the point is in this case - just neater?