Pulsacoil 2000 wall switches and Economy 7

I get more and more texts, emails etc than ever nowadays asking me about tariffs for the Pulsacoil, and also about the three switches  usually on the wall next to a Pulsacoil. Stand by, this rapidly gets complicated. There are several things to explain. This is SUCH a complicated subject you may need to read it over and again, but here goes…

Concept one:

It is important to understand the nature of off peak water heating. Electricity generation broadly runs all day and all night, meaning there is surplus electricity available at night, so the electricity suppliers can offer tariffs that sell night-time electricity at a lower price that daytime electricity. For many years this was known as “Economy 7” tariff, where a unit of electricity used during the 7 hours between midnight and 7.00am was priced at about half that of the same unit of electricity used in the daytime. This made it cheaper to run washing machines, heat hot water tanks etc at night. Nowadays most electricity suppliers have a low cost off-peak tariff like Economy 7 but it may not actually have that exact name. Check with your supplier to see if you are on such a tariff as the Pulsacoil is designed to heat up at night using this low cost electricity. Ok so far? 

Concept 2:

To make sure your Economy 7 hot water tank (of which the Pulsacoil is a type) uses mainly low cost cheap rate electricity, the electricity meter installed in your house or flat will have two outputs. One is connected to your wall sockets, lights, cooker etc and supplies electricity 24/7 so the electrical things you need to work in the day can run on daytime electricity, and the other output is connected to all your Economy 7 appliances including the night time heater elements in your Pulsacoil. This output is switched on automatically by the electricity company at midnight to coincide with the price of their electricity dropping no night rate price, and off again at 7am when the price goes back up again. The plan is, you will get one whole tank full of hot water heated using low cost electricity to last you the whole day until the heater gets turned back on again the following midnight for re-heating.

Concept 3:

Should you run out of hot water during the day, this demonstrates your Pulsacoil (or other E7 hot water tank) is not big enough for your needs. The slow and expensive answer to this is to fit a larger Pulsacoil so you’ll have more cheap rate off peak stored hot water. Few people however are in a position to do this (least of all tenants in rented flats) so another solution is provided. A day-time ‘boost’ heater element is fitted to most Economy 7 water tanks including the Pulsacoil, for you to manually turn ON to get some more hot water now instead of having to wait until the next night-time re-heat. 

Concept 4:

The Pulsacoil has a control board, sensors and a pump which need to run whenever a hot tap is ON. These need a power supply in addition to the power supplies feeding the off peak heater element and the ‘Boost’ element.

Concept 5 - tariffs:

Back if the day there was only Economy 7 off peak tariff (and when dinosaurs walked the earth, “White Meter” tariff). Nowadays there is a plethora of options from the dozens of leccy suppliers but all of them have a basic ‘low cost off peak tariff’ equivalent to Economy 7. Nowadays there are not only off leak tariffs but also horribly misleading tariffs where you are offered a fixed quantity of high priced leccy in a billing period followed by access to unlimited low cost units until your billing period runs out. These are best avoided as supremely unsuited to use with Pulsacoils in my personal opinion. 

Concept 6 - the wall switches:

If all the above made sense, hopefully it is clear why a Pulsacoil 2000 needs three separate electricity supplies. One for the off peak heater element, one for the ‘Boost’ element and one for the control board, pump, sensors etc. Consequently there will be three wires from the Pulsacoil to the wall, each having a switch (or at least an isolating fuse) in the wall connection plate. The control board switch needs to be ON all the time. The off peak Economy 7 switch needs to be left ON all the time too, although if it has a red pilot LED indictor this will go out during the day to demonstrate the meter is correctly turning the supply ON only between midnight and 7am. The third switch is for the ‘Boost’ heater element and is normally OFF to prevent it routinely drawing expensive daytime electricity. It is for you the user to turn it ON manually when needed for extra hot water, and for the user to remember to turn it OFF later too. 

Variations from the above:

Sometimes the E7 meter is not in the flat with the Pulsacoil in which case there is probably a time switch to perform the switching function otherwise carried out by the E7 meter. When an E7 time switch is fitted, there will usually be a “Boost” function built into the time switch, and only two wall switches, both of which need to be kept ON all the time.

The Pulsacoil A-Class has a “Boost” button on the user control panel of the appliance itself, so the appliance only needs two wall switch supplies both of which need to be ON all the time. 

The Pulsacoil Original and Pulsacoil BP are both ‘passive’ in operation and do not have a control board, pump etc. So they only have two cables and wall switches feeding them, one permanently ON from the E7 supply, and the other being the ‘Boost’ which is normally OFF and turned ON when needed by the user. 

In addition to all the above I recorded this short video about Economy 7 a year or two ago, which may shed some light in a different way. 

I hope this makes sense as I’ve written it all in rather a hurry very late at night. I may well edit and change it when I read it again in the cold light of day…. In the meantime feel free to text me questions if I’ve left anything out or if something makes no sense at all, highly likely! …. :)

Mike