Economy 10 Tariff electrical connections.

[Taylortwocities]

Does anyone have experience of connections for this??

My customer is having a Heatrae Sandia Electromax system. This suggests use of Economy 10 tariff for the hot water connections.

I need to know, when Economy 10 is supplied, do we need to install a separate off peak fuseboard or is it simply that the meter clocks up a separate counter during off peak periods.
Either way it has implications for the installation.

Thanks for your advice.

 

[Lectrician]

It is just a meter swap.

The Electromax does not need to be controlled by the teleswitch or time clock.

The electromax is two systems in one. For hot water, there is a 3kw immersion in the tank. This needs time control. There is also a 9kw (or more) flow boiler to heat the water for the rads. This requires time control.

If you used the timed output of the meter, you could only have heating at those times! Thats why econ10 is better, as it spreads the cheap period through the day.

We have fitted these, and similar models. We always fit a standard two channel central heating timer with room stat. We then use the hot water output of this time clock to fire a contactor which brings in the immersion element. It makes the controls more traditional then, rather than having different time clocks.

There is a model of Electromax with build in controls aswell I think?





Bottom line - just run a 16mm split or larger from CU to electromax. Fit a 4 way CU there for the immersion, the electromax, and any controls required. common to fit an RCD board, as the flow boilers state RCD protection.

 

[Stoday]

You may have a problem getting Economy 10. No supplier quotes it on their web site.

 

[ub7rm]

I managed to get economy 10 from scottish hydro only because the economy 7 meter wouldn't fit! The whole flat benefits from cheap rate at the off peak times, the meter just records kw's used on two different rates. By the looks of the meter though it can be set up to feed two cu's if required.

 

[Lectrician]

The meters are all generally identical, and programmed depending on the tarriff!

They all usually have a terminal rated at 80amp for switching storage heater type loads, but all lecky is cheap at night.

 

[Taylortwocities]

Hmm. I've to consult with customer on some things here.

As far as I can see on the Electromax boiler he really should have the 40A main supply on constant feed with a timeclock to take advantage of the cheap rate but also have the option for heating at other times
1 immersion on off peak only
1 immersion used as boost

Is that how it usually works Lectrician?

However, estimated demand may be a problem here as they will have

Electromax 40A
2 x immersions 26A
Kiln 30A
On top of that there is the usual
2 x ring
lights etc

I cant discount the load on the first three so thats mighty close to 100A when they run the kiln & the heating at the same time. They'll be able to warm their hands on the supply fuse though.
PS its TT so RCD will be there already.

 

[Lectrician]

Some have one immersion, some two.

If there are two, the lower one is best fed from a CU controlled by the meter, and the other on the peak supply for 'boosting'. The flow boiler (40amp for your model) should be on the peak side, so heating is available 24/7, but will still be cheaper during the off peak hours.

I have fitted so many of these systems, both electromax and other makes. Get the model number of the one to be installed.

 

[Taylortwocities]

Thank you, some things to bottom out with him and I'll get model number.
In your experience is there any trade off between running separates from the main board or 16mm with a secondary board?

This is a TT by the way hence no gas and he doesnt want oil tanks.
Pig on pole across the drive.

 

[Lectrician]

Every system is different.

I am beginning to wonder if the electromax has one or two elements.....The one I fitted recently deff had only one. I guess there must be models with two.

If you need to connect to off peak DB, then you need atleast two cables, so it would make sense just to run all cabling back to main DB position.

If it was all peak supply, I would run the submain.

 

[Taylortwocities]

Thanks

 

[Taylortwocities]

H lectrician.

Customer says the only ref he can find is 95:022:203. he's talked to Heatrae and there is only one Electromax model for domestic central heating

Per previous post. Requires a 45A for the heating and 2 x 13A for the immersion heaters.

So I think I'm sorted - still have a max demand discussion re the Electromax + kiln + general house stuff but there you go. Thanks for your input..