Help with my new electrisaver and how my hot water works

[studentofleeds]

Hello people,

I have just moved into a new flat and been left with no instructions as to how my hot water works. I have set the timer so that it comes on in the morning and evening, however this is not always appropriate as at weekends I may need it during the day etc.
Also, my dad reckoned that the hot water should stay hot for quite a while, I tried to have a shower last night just under two hours after my hot water timer had gone off and the shower was freezing cold.

What I need to know is what is the switch on the left for? When do I use it and when do I use the Horstmann Electrisaver? Is my timer configured correctly?

I'll whack some pics in to show you, ignore the fact the lights are on I was just fiddling about with them before.

Thanks !!

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• studentofleeds
• 20 May 2015
• 1

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• studentofleeds
• 20 May 2015
• 1

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• studentofleeds
• 20 May 2015
• 1

 

[stem]

There are two heating elements fitted to the cylinder, and I have assumed that they are installed as follows: [Check where the cables run to and from to be sure]

The bottom element is connected to the time switch, which should only be set to be 'on' for most of your 'off-peak' (or night-time) electricity supply period. (but don't run over into the 'peak' rate period) This will heat the whole of the cylinder during the night at the cheaper tariff and it should last you for most of the day. Once the water is hot, the thermostat will turn the heater 'off' so it won't be using energy all of the time. Do not have it set to be 'on' during the morning and afternoon as you are doing. It will cost you much more to run. [There may be an occasional exception which I will explain later]

The top element is designed to heat just the water at the top of the cylinder as a 'top-up' should you run out of hot water later in the day. It will only give you enough hot water for washing the dishes and general ablutions or possibly a quick shower. This would normally be connected to the electrisaver which will operate the heater for just long enough to heat this small amount of water and then automatically switch 'off' to prevent you using 'peak rate' electricity unnecessarily.

If during the day, you run out of hot water and need to use a large quantity of hot water, then you will need to manually override the time switch and turn on the bottom element, but if you do this whilst your 'peak rate' tariff is in operation you will be charged accordingly.

You will need to check with your electricity supplier regarding your 'off peak' times. The tariffs are often referred to 'Economy 7' which is operative for 7 hours during the night, or 'Economy 10' which also has additional 'off peak' time in the afternoon. If you do have an afternoon 'off peak' period, then set the time switch to be 'on' then also, to take advantage of it.

The switch on the left [Fused Connection Unit] provides the power to the time switch and should be left permanently 'on' to keep the clock going. I would also have expected to see an FCU or at least an isolator for the top element, however, it may have been removed at sometime by someone who has replaced it with the electrisaver.

 

[studentofleeds]

Thank you for your advice but now I am even more confused because the timer works without the switch on the left being on! Do you know why?

Also I am a tad confused what you are referring to as the top and bottom element? The box just has a boost button on it...

X

 

[stem]

The timer works without the switch on the left being on! Do you know why?

Probably because it has some form of battery back up which will keep it going for a while in case of a power cut. If it has a make / model name on it, do an internet search and see if you can find the instructions for it.

Also I am a tad confused what you are referring to as the top and bottom element?

There are two heating elements inserted inside the hot water cylinder, the two cables entering the side of the cylinder show you where they are.

The top element connected to the electrisaver just heats the water immediately above it and is used as a top up, probably enough for a couple of sinks full and is used in the daytime if you run out of hot water. Try not to use it unless you have to, it costs more to use electricity during the daytime peak rate.

The bottom element connected to the time switch also heats up the water above it, which in this case is the whole cylinder. This should be used at night to heat up as much water as possible during the time when the electricity is at a much cheaper rate.


Here's a sketch. Hope it helps

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• stem
• 20 May 2015
• 1

 

[flameport]

That Grasslin timer has no battery, so the switch is wired incorrectly or has failed internally.

 

[stem]

Maybe when referring to "timer" studentofleeds means the electrisaver (not the time switch as I thought) In which case, it would be correct that the switch on the FCU doesn't turn it off.

 

[Madrab]

First things first. Check to see if you are on Economy 7 tariff with a dual supply.

Do you have 2 electric meters or a digital meter with 2 readings?

Secondly, the far left switch should power the timer (that controls the bottom immersion element to heat the whole tank) on the far right. Set the clock to run within the economy period to heat the whole tank. If you turn that off and the clock still runs then it could be wired incorrectly, or has a separate feed for the clock.

The booster switch in the middle controls the top element for hot water in a hurry, it will probably have a direct fused feed from the consumer unit above.

I'd get in touch with the landlord, it is his responsibility to ensure everything is wired ok and that you are familiarised with how it all works.