Unvented hot water cylinder (electric)

[AidanGee93]

Advice please?  (Attached pics)

Got unvented hot water cylinder in a flat (1995 build) I just purchased, fully electric flat no gas.

The unvented hot water tank has two switches...

1 is off peak supply (through the night it runs only- cheaper prices).

Other is 24 hour on demand so heats at any time throughout day (peak times so normal elec rates).

But...There's a third switch (in kitchen)....

 

So I plan leaving off peak switch on and others off so that tank heats up during night and is hot enough next day as I know if left 24hr on, the tank would constantly heat up to a required temp via thermostat so using alot of electricity...

 

I was told that if I wanted a bath say, and the hot water wasn't as warm as I'd have liked (Ie last heated in the tank night before)I can switch on the 24hr switch for hit water in demand...which makes sense.

 

My question is, following on from above I was told I'd have to switch the kitchen socket (silver switch) on along with the 24 HR supply switch to achieve the on demand hot water? Does this sound right...or is it possible that the silver switch located in kitchen is for hot water on demand to the kitchen sink?

 

Also told if just showering and no baths just leave the off peak switch on and rest off so uses as little electriciy as possible.

 

Any tips on this would be great before I waste a small fortune.  It all makes sense just the third kitchen switch is throwing me off a little like why is it there and not just use the switch marked 24hr next to off peak??

 

Any help much appreciated.

[SteamyTea]

You can usually hear an immersion heater work by the fizzing sound.

So during the day, try keeping the kitchen switch off, and flick the 'Peak Supply' switch on, you should be able to heat some noise from the cylinder, or you can check the meter and see if you have an extra 3 kW load on.

The kitchen switch may be just a secondary switch to make life easier i.e. not having to open a cupboard.

 

Most of us on here like to keep water temperature as low as possible to save parasitic losses.

I have a 200 lt DHW cylinder and store, via E7, water at 50°C.  That is enough for a bath and a shower.

 

Check the thermostats as the upper one (peak) should be higher temperature than the lower one (off peak).

[ProDave]

The clue is in the writing on the right hand switch.  It says "Kitchen switch"

 

So leave the 2 in the cupboard always on.  The tank will heat overnight on the off peak.

 

Then IF you have used up all your hot water before the end of the day, you can turn on the switch in the kitchen and that will top up the tank from the peak rate.  It saves you having to go to the cupboard to do so.

[JohnMo]

12 hours ago, AidanGee93 said:

fully electric flat

Have you thought about a different tariff other than E7? Octopus does one for storage heaters, three cheap periods, one expensive period, and the rest of the time standard tariff. Instead of one long off peak and one very long expensive period.

 

Then just drive immersion via an immersion time switch and allow to top up every cheap period, so you never run out of DHW.

 

You would need a smart meter and time other heater via a time switch also.

[Nickfromwales]

2 consumer units, so possibly 2 meters? E7 loads on one, other on the second. Not sure how this could be run off a new supplier / discipline. 
 

Off peak immersion via kitchen switch will be E7, and the other immersion will be off peak rate 24/7 CU. 

[AidanGee93]

Guys, thanks to all you're comments...Found them really helpful!

Plan is to phone current supplier find out their peak times and go with off peak supply...hoping be enough for throughout the day .ie showers hot water for dishes etc so should be fine. Will bare in mind about octopus energy and give them a phone as be handy for my electric heaters. (Realising smart meter needed).

So plan is to leave my off peak switched on all the time.

 

Q... (Double checking)

I know the kitchen switch is the booster switch if you like for 24 hour supply hot water to activate if needed (i.e used all hot water that day and wanted a Bath in evening say).  Will I leave the cupboard 24hr switch supply on ALL THE TIME and the only way that will heat is if I switched kitchen switch on so it's acting like a breaker when switched off?...so without both switches on the 24hr heat won't activate?

 

To test that's the case I'll knock peak supply switch,24 HR switch and kitchen switch all off and should be quiet.  Will then switch 24hr on hopefully still quiet, next put kitchen switch on and if I hear any noise in cylinder I know that's the case. If that appears correct using kitchen switch with cupboard 24 HR supply switched off won't work.

 

Bit long winded above just means if all correct I can get other important things rectified in flat before coming back to this matter with no big electric Bill waiting for me.

 

Cheers again guys!

[AidanGee93]

This is my 2x consumer units that are fitted. Hopefully sheds more light...

[Nickfromwales]

13 minutes ago, AidanGee93 said:

Q... (Double checking)

I know the kitchen switch is the booster switch if you like for 24 hour supply hot water to activate if needed (i.e used all hot water that day and wanted a Bath in evening say).  Will I leave the cupboard 24hr switch supply on ALL THE TIME and the only way that will heat is if I switched kitchen switch on so it's acting like a breaker when switched off?...so without both switches on the 24hr heat won't activate?

 

To test that's the case I'll knock peak supply switch,24 HR switch and kitchen switch all off and should be quiet.  Will then switch 24hr on hopefully still quiet, next put kitchen switch on and if I hear any noise in cylinder I know that's the case. If that appears correct using kitchen switch with cupboard 24 HR supply switched off won't work.

Correct.

 

I doubt you need to double check, as this is a standard setup. 
 

Breaker in the peak rate CU > kitchen switch > RHS switch at cylinder. 
 

Breaker in the off peak CU > LHS switch at the cylinder.

 

As said the kitchen switch is for those who fully fill that cupboard with ‘life valuables’ and ergo can’t get in there to easily flick the RHS (aux hot water) switch on / off.