Economy 7 water heating

[dnjr]

Dear all
This may be a stupid question so have flame proof trousers on
I'm doing a refurb at the moment
No gas at the property so hot water is electric
Plumber is putting in a new dual immersion tank and the property has economy 7
I was going to run two supplies to the tank . One to the economy 7 board and one to the standard board
Now I'm wondering if this is right as you would then have two feeds at the tank and could in theory have them both on at the same time, if the standard element was left on.
i know both would be controlled by the stats so should not overheat but I'm unsure about wiring them

be gentle

thanks in advance

dnjr

 

[Buckfast]

I would use a Horstmann Economy 7 Quartz time switch for this. This requires one 24hr 230V supply and has time clock which stops both elements being on at same time and also time clock only allows bottom element to work during off peak period. Pretty bullet proof.

 

[Richard Burns]

If you have two separate supplies then use a dual input boost controller such as the horstmann BX2000, this will accept a supply that is only on during off peak times and a supply that is permanently on, the off peak being the priority so that the on peak will switch off if the off peak comes on.

The bottom immersion element is for the off peak supply and the top immersion element is for the on peak supply, or if there is a dual element in the top the tank then the shorter element is the boost (on peak) heater.

This option does depend on there being two separate supplies incoming to the controller, if the entire installation is switched over to economy seven at the specific times rather than having two consumer units then the E7 quartz is the answer.

 

[dnjr]

If you have two separate supplies then use a dual input boost controller such as the horstmann BX2000, this will accept a supply that is only on during off peak times and a supply that is permanently on, the off peak being the priority so that the on peak will switch off if the off peak comes on.

The bottom immersion element is for the off peak supply and the top immersion element is for the on peak supply, or if there is a dual element in the top the tank then the shorter element is the boost (on peak) heater.

This option does depend on there being two separate supplies incoming to the controller, if the entire installation is switched over to economy seven at the specific times rather than having two consumer units then the E7 quartz is the answer.

Thanks to both of you for your help. Im guessing that as I have two supplies( one unrestricted) then the BX2000 is the way to go. Much appreciate the help

dnjr

 

[dnjr]

Hi Richard
still re thinking this, I'm sure I have seen installations with an unrestricted supply and an Eco 7 supply both direct to switches then the elements without any other form of control. Is this acceptable and just 'not best practice ' or is it completely wrong ( if wrong why?)
sorry to re question but I like to learn as well as solve the issue

thanks again
dnjr

 

[Richard Burns]

If you have two independent supplies, one 24hr and the other on during E7 times only.
Then each supply goes to its own immersion element in the tank and each one has a manual switch, this is OK.
There is no need for a time control because the off peak board is only on during E7 times.

The usual method of switching would be to have the switch for the off peak element on all the time, if a boost heating of the water were required then the second on peak switch would be turned on.
There are also available boost timer switches that allow you to just turn on the 24hr supply for an hour or two hours then it switches off, these are useful so that the element is not left on the expensive rate all the time by mistake.

 

[dnjr]

If you have two independent supplies, one 24hr and the other on during E7 times only.
Then each supply goes to its own immersion element in the tank and each one has a manual switch, this is OK.
There is no need for a time control because the off peak board is only on during E7 times.

The usual method of switching would be to have the switch for the off peak element on all the time, if a boost heating of the water were required then the second on peak switch would be turned on.
There are also available boost timer switches that allow you to just turn on the 24hr supply for an hour or two hours then it switches off, these are useful so that the element is not left on the expensive rate all the time by mistake.

Thanks for your clear and very helpful reply Richard much appreciated
Ive no idea how to 'thank' people on the site but the thought is there and if I find it I will click with pleasure