Economy 7 & Hot water

st76

In our flat, we only have electricity and on Economy 7.

the problem is with hot water - it only heats up once a day (ie from 10.30pm, and how long for, not too sure) so by the time 1 person had shower, there isn't enough hot water for the second person hence what we do is 1 has shower in the morning and the other at night (it can work out all right) but this can be a bit inconvenient sometimes as you can imagine.

Now, how do we go about rectifying this problem (we want hot water all the time)? is this hot water business as a result of being on Eco 7 or is it the fault of our boiler? or combination of both? Boiler has no thermostat or timer. what/who controls the boiler to come on at certain time of the day, how does it know when to heat up (only once a day, hasten to add) such a mystery to us....

electrical/plumbing issues are not our strongest points (no knowledge to be honest!), we thought about changing to Standard Tariff (we seem to use more electricity during the day anyway), or do we need new boiler? what do we have to do??!! so many questions... sorry.
could anyone give us some advice, please?! please please!

Thanks very much.

Cardew

I assume by 'boiler' you mean the immersion heater in the hot water tank?

Firstly, timing of switching on. I don't think Economy 7(E7) ever comes on as early as 10:30pm.(unless the clock is faulty)The normal timing is a 7 hour period between, say, Midnight and 8am.

I assume your heating is by Storage Heaters? If so they will come on(ie heat up) at the same hours as above, and release their heat during the rest of the time.

You should be able to see by looking at your electricity meter and(normally) the dials below exactly when E7 comes on and goes off.

Immersion heaters are usually wired to come on during the E7 period. However I have not heard of an immersion heater that does not have an overide facility to enable it to be switched on outside of the E7 period.

'Boilers' work or they don't. As yours provides hot water it doesn't need to be replaced.

The question about the viability of changing to standard tariff is not possible to answer without more information - especially your heating method. You almost certainly should be on E7 if you have storage heaters. If you don't have night storage heating, you need to work out if E7 or Standard tariff is best. It is simply not possible to give an answer as it depends on the proportion of Electricity you use in the E7 period, the area of the country you live in and your supplier.

st76

Cardew, thanks for your reply.

Sorry if the first post wasn't clear. You're right, I'm talking about hot water tank.
there are 2 wires with swtiches on the wall, 1) W/Heater wire that goes to the middle of the tank 2) big swtich with red light goes to the bottom. They are both on.

I just looked at the meter/radio teleswitch box, there seems to be no time written as to when E7 comes on and off. I know we're on E7 because our bill states 'Economy 7 Domestic Tariff' (live in London and supplier is Seeboard EDF)

As for Heater, we think we have storage heaters but it can always be ON (with a switch on the wall). We also have a switch on the other side 'off peak' but that is not on.

our latest bill was that during the day we spent £115.30 and £16.63 at night. don't think we're getting the best out of E7 because we use washing machine when we want, heaters on when we need it etc.

is it any clearer?! Thanks

irnbru_2

st76 wrote:

As for Heater, we think we have storage heaters but it can always be ON (with a switch on the wall). We also have a switch on the other side 'off peak' but that is not on.

our latest bill was that during the day we spent £115.30 and £16.63 at night. don't think we're getting the best out of E7 because we use washing machine when we want, heaters on when we need it etc.

You're definately not getting the best of your E7.

If you have storage heaters, they should only charge during the E7 period. Try to get the manufacturer and model numbers. maybe you just have panel heaters.

You should consider getting an electrician to fit a timer for the immersion heater. An on/off switch isn't practical with E7.

paul_h

st76 wrote:

I just looked at the meter/radio teleswitch box, there seems to be no time written as to when E7 comes on and off. I know we're on E7 because our bill states 'Economy 7 Domestic Tariff' (live in London and supplier is Seeboard EDF)

As for Heater, we think we have storage heaters but it can always be ON (with a switch on the wall). We also have a switch on the other side 'off peak' but that is not on.

our latest bill was that during the day we spent £115.30 and £16.63 at night. don't think we're getting the best out of E7 because we use washing machine when we want, heaters on when we need it etc.

If you are on a RTS, your supplier should be able to tell you the economy7 times, although they are usually around midnight to 1am, for seven hours.

A timer for you immersion heater is a good idea. It may be supplied by the off-peak supply only - I have seen this arrangement before and it will not supply enough hot water - you need to be able to boost it during the day. It would be a good idea to get an electrician to check out how it is wired. You really need a timer and a standard supply so that you can take advantage of the off-peak electricity at night for a tank full of hot water in the morning, and be able to give a boost with peak-rate electricity later in the day, as required.

Your heaters sound like they may be combination storage heaters if they have two supplies, one marked 'off-peak' - is it a fairly modern installation? You might need to do a bit of homework...

Assuming they are combination heaters, then they work a little differently to normal storage heaters. Firstly, you need to make sure the 'off-peak' switch is ON. This charges the storage heater on cheaper off-peak economy7 overnight and releases it during the day. There is probably no input control to fiddle with as it's usually automatic on these models, but it will take a few days to settle down. The storage heater part is slightly smaller than would usually be the case, but it augmented by an additional convection or fan heater in the same unit - this is supplied by the other connection and provides an evening boost to the room temperature.

There are a number of different types of these combination heaters, it would be a good idea to contact the manufacturer and get a user manual if you don't have one - it will tell you the best way to operate them.

Hope this is of help! :j

st76

this is all helpful, thank you.
so all I need is a timer for immersion heater?!
can someone tell me though, why we have 2 switches on the wall, wired to the tank? could one of them be the switch to heat up water when needed? (over ride facility as Cardew says?) it doesn't seem to do much though, we're always running out of hot water by the end of the day.

paul_h

st76 wrote:

this is all helpful, thank you.
so all I need is a timer for immersion heater?!
can someone tell me though, why we have 2 switches on the wall, wired to the tank? could one of them be the switch to heat up water when needed? (over ride facility as Cardew says?) it doesn't seem to do much though, we're always running out of hot water by the end of the day.

From your description, it sounds like you have a proper economy7 cylinder - I assume there are two switches with separate cables connected to separate immersion heaters. Standard cylinders usually have the immersion heater head on the top, economy7 cylinders usually have the two heaters on the side of the cylinder.

If you have, there is no need for a timer - the lower of the two heaters will be connected to the economy 7 circuit and will use off-peak electricity to charge the cylinder with hot water overnight, the upper heater is for boosting the hot water if you require more hot water later in the day - as it is higher up, it heats up less of the cylinder to save electricity - you rely on the off-peak heater for the bulk of your hot water. If the bottom heater is not on overnight, that will explain why you are running out of hot water.

First of all, identify which switch is for the top immersion heater, and which is for the bottom immersion heater.

Leave the heater at the BOTTOM switched ON all the time, it will only come on at night, using cheap off-peak electricity.

Switch on the TOP heater as/when required if you need more hot water later in the day - this is the boost heater and uses peak rate electricity.

Some leave the boost on to maintain the cylinder water temperature during the (there is a thermostat in each immersion heater) but it will increase electricity usage. However, economy 7 cylinders are bigger than standard ones and should provide most of the hot water needed if fully charged overnight on off-peak electricity.


I hope this helps you on your way to lower bills!

paul_h

Oh, and welcome to MSE! :j

st76

Paul_h, I think you got it so right!

1st main switch is wired to the bottom of the cylinder and the 2nd switch is connected to the middle of the tank. we used to leave both switches ON all the time, is that wrong? could it have damaged something in any way? Having switched off the 2nd switch, we now have to see how it goes. Thank you so much for your help/advice, so good to find out what's what. this is one of those things that we don't really think about everyday! as we speak, red light has come on on the main switch (this must be the time when eco 7 kicks in, i guess? as the time is not written on the meter)

So having a proper Eco 7 cylinder and obviously on Economy 7 tariff, we can't change to Standard tariff? we use a lot of electricity during the day. I mean, does it cost a lot to heat up water during the day?

paul_h

One other thing which just occured to me, something I have seen before with an economy7 cylinder which wasn't providing enough hot water.

If the bottom heater fails, people often don't realise because the top boost heater takes over - the only difference being that there's not as much hot water available.

The way to test it is to leave the bottom off-peak heater ON overnight, but make sure the top boost heater is OFF. If you cylinder is still cool in the morning, then the bottom immersion heater has failed.

I've seen cases where the only time this has come to light is when the top heater has failed as well, and there's been no hot water at all.

Even if it's not the case with your's, it's something to watch out for...

paul_h

st76 wrote:

1st main switch is wired to the bottom of the cylinder and the 2nd switch is connected to the middle of the tank. we used to leave both switches ON all the time, is that wrong? could it have damaged something in any way? Having switched off the 2nd switch, we now have to see how it goes. Thank you so much for your help/advice, so good to find out what's what. this is one of those things that we don't really think about everyday! as we speak, red light has come on on the main switch (this must be the time when eco 7 kicks in, i guess? as the time is not written on the meter)

So having a proper Eco 7 cylinder and obviously on Economy 7 tariff, we can't change to Standard tariff? we use a lot of electricity during the day. I mean, does it cost a lot to heat up water during the day?

Leaving both switches on won't do any damage, but you will use more electricity as the boost heater will keep the cylinder 'topped up'. The ideal situation is to have used all the hot water when you go to bed.

Sounds like your economy7 starts a bit early, but it's not unusually so. If your economy7 is now on, you should now be able to feel the bottom heater starting to warm the cylinder with the top one turned off.

You really need the economy7 supply for storage heaters and economy7 hot water, but bear in mind that economy7 off-peak electricity is about 1/3 the price of standard tariffs. If you have no access to mains gas, economy7 is currently one of the most economical options for heating, despite it being a pain to get used to.

You very welcome to the advice, I'm glad I could be of help! :j