Immersion Heater TImer

Scott1313

Hi everyone [!!!8203;IMG]

I have just moved into a new house that is all electric. The previous owner had started transitioning from Economy 8 to a new system by removing some of the storage headers and replacing them with electric radiators. Currently they have a Economy 8 meter (from SSE) and an Economy 7 water heater control panel without a timer (Horstmann one), it just runs from midnight to 7 or similar.

My electrician says if I want a timer on my water heater I need to get an Economy 7 compatible version and not just a standard immersion control timer (Like a Timeguard one) as the wiring is different. I would want a timer as I want a standard tariff (not economy 7/8) and don't want to run it during the night on normal tariff energy.

My electrician wants to use the Economy 7 control panel but my power company wants to give me a smart meter. If I get smart meter (or even a new non smart meter) should I get a Timeguard style timer or go with the Economy 7 one my electrician suggested?

Sorry for the long winded question. Thanks in advance!

Richie-from-the-Boro

IMO

- you do not want a SMETS1 smart meter ever, and you do not have to have one under current law.
- the previous householder chose to spend a wad of money moving from E7/8 stored heat & heated water setup.
- the whole wiring and control system is thrown into chaos and 30% more expensive than the old system.

I would reinstate the NSH on E7 not E8, particularly if you are in Scotland, the Smart meter is just simply a nono. You decide on this first then come back for further advice. Beast of luck.

AndyPK

If the tank has 2 immersion heaters (maybe you have a sink/bath switch? or some timer top up, that maybe why the sparky wants to fit an E7 one.

Otherwise, yeah you far better off with a normal 16A timer.

Possibly a switch for the 2nd heater if you have one, as a backup or top up

Scott1313

We are a little unsure how it works. Along with the Horstmann panel there is a switch labelled "Water Heater". I'm not sure how that works, I'm thinking it must be connected to the boost system?


There are two tanks but I'm assuming one is cold. The other is a standard dual immersion cylinder.



He had said it must be an E7 timer and not a regular immersion one. I'm assuming though if the meter is changed the switch will need re-wired anyway as the peak/off-peak is no longer applicable. I believe the Horstmann panel has two cables running into it, one for peak and one for off peak.

AndyPK

So it is dual element then.

Can't comment on the E7 wiring. There are different ways.

Richie-from-the-Boro

Bog standard they have been around for 60+ years. @ night-time the E7 switches [radio 4] automatically to a cheap rate and the Hortstmann contactor safetly isolates + switches OFF the top boost element and on the bottom element for 7 hours. 10 hours of course for E10.

Reproduced from an old post of mine 8 years ago here Scot1313

If its an E7 / E10 / or E anything spec it should already be PartL spec, due to the higher than normal storage temperatures the capability of the insulation to preserve the temperature of the water the type of insulation has a very very low standing heat-loss [one kW per day (kWh/24h) on a 125 litre cylinder] permissible thermal transfer rate from the 60mm of insulating foam, modern ones have the additional benefit of recessed immersions and thermostats to reduce even further energy wastage. All dual PartL cylinders have a top up facility ([here's yours]) [see below] and is usually operated by a standard 60 minute top-up water controller such as the Horstmann unit also shown below. Yours is a modern version of the picture below and is as Owain Moneysaver said a boost timer only for variously water hearing, panel heaters, towel rails etc.

Hortsmann is a good quality water heater designed for E7 / E10 / or E anything spec and able to have x2 separate 3kW heating elements installed, this water controller ordinarily tele-switches the cheap rate night element on and off [automatically and out of your control] at the bottom of the tank. The other top element is the boost element controlled by yourself on expensive day rate.

If you do not touch the E7/10etc boost controller and you get a tank of nice hot water every morning its still tele-switching on and off. You have checked your tariff and get 'cheaper rate electricity between 12:30am - 7:30am'. You've stated you've got x2 elements both with wiring going to the tank.





The top element [top-up-day rate] will give a couple of big sinks of hot water when used, the bottom element [E7-night rate] will give a full bath and a couple of sinks of hot water. Heat loss is not linear to the volume of water, the bigger the mass the slower the loss rate, eg [figured below are 'ish' but about right] :

1 kW per day (kWh/24h) on a 125 litre cylinder
1.5 kW per day (kWh/24h) on a 250 litre cylinder
2 kW per day (kWh/24h) on a 300 litre cylinder

Hope this helps your understanding of your existing installed setup, and answers a few of your queries.

AndyPK

And some houses use a timer by the meter rather than radio controlled.

And some houses the whole house goes over to E7 at night, others just enable the off peak consumer unit (fusebox)

Scott1313

Thanks guys this has all helped me. I've got plumbers and electricians coming along with the power company so I'll see what they suggest now that I know what to ask.


Think it might take a little trial and error as well!


Thanks everyone!