Off Peak Heating - Circuit Design

[Midwest]

I wonder if anyone can offer advice on storage heating circuit design.

I have a job to replace two BS3036 fuse boards, with 17th Edition consumer units. One of the boards will manage the existing storage heaters for the property, currently three heaters, old & no idea of size but each fed via 15amp fuses and 3kw immersion heater. This board receives an 'Economy 7' supply. The property also has 8.5kw electric shower, fed from the standard supply.

My client wishes to increase the storage heaters from three to six. The property has a 100amp supply. Clearly I will need to calculate the new demand, but even just basing it on 2.5kw heaters and the immersion, that is 64amp approx. If the client uses the shower at the same time as the heaters receive their charge, that is approaching 99amps.

I have already advised my client, but if I install 6 x 16amp circuits, there is potential to overload the DNO fuse.

Never installed an off peak board before, I've considered having a DP MCB as a main switch to prevent overload of the DNO fuse, or is it just case of calculating maximum demand for the normal tariff board and limiting the number of off peak circuits?

 

[Leesparkykent]

I know this is a more expensive alternative but you could talk to the customer about the benefits of installing an electric boiler with a wet system. It offers so much more flexibility of heating a home and can provide heat whenever it is needed and/or wanted.

The boiler itself could most likely be installed in the same place the existing cylinder is now.

 

[Midwest]

How much approx.?

 

[Leesparkykent]

How much approx.?

Around 2.5 bags of sand including labour with 6 rads. But would make the property more desirable if it's ever sold etc

 

[londonfire]

Are the electric boilers above cost effective in comparison to gas Leesparks?

 

[yellowvanman]

I wonder if anyone can offer advice on storage heating circuit design.

I have a job to replace two BS3036 fuse boards, with 17th Edition consumer units. One of the boards will manage the existing storage heaters for the property, currently three heaters, old & no idea of size but each fed via 15amp fuses and 3kw immersion heater. This board receives an 'Economy 7' supply. The property also has 8.5kw electric shower, fed from the standard supply.

My client wishes to increase the storage heaters from three to six. The property has a 100amp supply. Clearly I will need to calculate the new demand, but even just basing it on 2.5kw heaters and the immersion, that is 64amp approx. If the client uses the shower at the same time as the heaters receive their charge, that is approaching 99amps.

I have already advised my client, but if I install 6 x 16amp circuits, there is potential to overload the DNO fuse.

Never installed an off peak board before, I've considered having a DP MCB as a main switch to prevent overload of the DNO fuse, or is it just case of calculating maximum demand for the normal tariff board and limiting the number of off peak circuits?

There not many people who'll have a shower after midnight!

 

[bradder]

Maximum off peak load is normally 80amps
normally 3 sizes of storage heater(bathroom heater can be smaller)
Dimplex heater sizes
small 1.7kw
medium 2.55kw
large 3.4kw
immersion heater 3kw
Ps:- these ratings were the same when 240v was used for calculations
as long as the house has a mixture of sizes of heater then the loading should be ok

 

[Leesparkykent]

Are the electric boilers above cost effective in comparison to gas Leesparks?

Gas is cheaper to run but if you don't have the option of gas this system is brilliant IMO.

 

[Resu]

There not many people who'll have a shower after midnight!

But maybe early morning!

Worth asking what are the chances of all the storage heaters actually being turned on? Let alone on full blast.

As a (slightly long winded) example - I live in a moderately sized 2 bedroom rented flat (spread over one floor) with 2 storage heaters - Hall (XL18) & Lounge (XL24) There is panel heaters in the bedrooms, plinth heater in the kitchen & fan heater in the bedroom. Currently we only have the Lounge one about 2/3 of the way, with leaving the doors open throughout the day it provides enough heat for the entire flat (around 20 deg). Through the winter we had the hall one on too (also being around 2/3 on) this kept the place warm over the worst of the cold no bother. The only time we have used any of the other heating is on the odd night recently when it's been colder stuck the panel heater on in the wee ones room (she won't sleep through if it's not bang on 20deg!).

Think I worked out it costs us about £3 a day to heat the place through the winter (both heaters on with occasional panel heater too).

 

[davesparks]

The heaters will all be operating on their thermostats once it's reached the early hours of the morning so the current demand won't be anywhere near as much as the initial couple of hours

 

[SPARTYKUS]

On the plus side for the leccy boilers, they may cost a bit more to run but they are close to 100% efficient

beat that wet pants

 

[Knobhead]

Does the control unit slope so that the water runs off it?

 

[Midwest]

Cheers chaps for the replies. Interesting about the wet electric heating, is it in it's infancy? Something to consider other storage heating.

 

[Leesparkykent]

Cheers chaps for the replies. Interesting about the wet electric heating, is it in it's infancy? Something to consider other storage heating.

https://m.youtube.com/watch?v=AxUCaDI7dgc

 

[Midwest]

Varying views on how much it cost to run, when I googled it. Don't think my customer will bother though.