Economy 7

[Rob]

Replacing a twin immersion cylinder later in the week. The top entry one is boost and the bottom one is E7. They're fed from separate FCUs - no timer control.

Plan on installing just a top entry immersion and a proper E7 and boost combined timer.

How does E7 exactly work? Can I just install my timer from the current permanently Live FCU and assume the timer will determine cheaper rate or does it have to be from the dedicated E7 feed?

Thanks

 

[JohnD]

why do you want just a top element?

What are the dimensions of the cylinder?

Is there a bath in the property?

 

[Rob]

Various reasons.

36x18

yes

So what about that economy 7 then....

 

[crystal ball]

Try doing a search of this site and wikipedia/google, all will be revealed

 

[Doggit]

If there's 2 FCus, then the electric supplier controls when they come on. If there's just one, then you need to install a timer to operate the lower element.

 

[JohnD]

Various reasons.

36x18

So you don't mind that the cylinder will never be heated more than two-thirds, and will be incapable of filling a bath.

 

[flameport]

How does E7 exactly work?

Several ways, but usually you either get:

a meter where the entire supply is switched to E7 - you must provide your own timer to switch on devices at the most appropriate time. Often provided to persons who are mistaken in believing they can save money by operating their washing machine at 2am.
Controllers for these require a single supply, and have a timer built in to switch the heater on at the appropriate overnight times. Usually have a boost feature also.

a meter with a separate output for E7 only - no timer is required as the E7 devices are only powered during E7 periods. Fairly standard for all-electric installations with storage heaters. There should be a separate consumer unit for the E7 circuits.
For these the simplest option is to just connect the element to the E7 circuit. For boost, a separate element is usually provided and wired to a separate day circuit, hence cylinders with two elements, lower element for overnight use, the top element for daytime boost.
Devices such as the BX2000 can be obtained for allowing boost and E7 from two separate circuits with a single element, and are normally only used where a single element cylinder has been installed where a 2 element type should have been.

 

[Rob]

So you don't mind that the cylinder will never be heated more than two-thirds, and will be incapable of filling a bath.

Ok John. Thanks for your advice

 

[ericmark]

Remember Economy 7 is a tariff not a system. There are many ways to use the tariff, although years ago we had white meters for off peak power, today there are many ways to use the tariff, often radio 4 was used to get a time signal to switch things on and off.

 

[winston1]

Often provided to persons who are mistaken in believing they can save money by operating their washing machine at 2am.

Why are they mistaken? Surely if the electricity is cheaper at 0200 they must save money.

 

[JohnW2]

Why are they mistaken? Surely if the electricity is cheaper at 0200 they must save money.

They save money in comparison with using the WM during the day with the same tariff.

However, I imagine that the point being made was that some people are misled into having E7 when their night-time consumption is not high enough to make it cost-effective. In that situation, given that daytime electricity is more expensive (and/or there is a higher standing charge) with E7, the total electricity bill is likely be greater with E7, even though whatever night-time consumption they have is 'cheap'.

Kind Regards, John

 

[crystal ball]

Remember Economy 7 is a tariff not a system. There are many ways to use the tariff, although years ago we had white meters for off peak power, today there are many ways to use the tariff, often radio 4 was used to get a time signal to switch things on and off.

The signal is still carried by R4 LW but will be phased out as smart meters can do the job I have been informed

 

[crystal ball]

duplicate deleted

 

[JohnD]

The signal is still carried by R4 LW but will be phased out as smart meters can do the job I have been informed

Or when BBC R4 LW ceases transmission, since the necessary spare parts for the transmitters have almost run out (controversial).

 

[EFLImpudence]

Remember Economy 7 is a tariff not a system.

Surely Economy 7 is the system.

The tariff can be increased (price rise).