Hot water runs out too fast!

th101

I live in a flat with electric heating, no gas at all.
There is a large water tank which has two switches outside the cupboard, off peak and on peak. As far as I'm aware if only the off peak switch is on it will only heat the water overnight, and the on peak will heat water at any time of the day.
However, there is almost never enough hot water to run a bath. Say if I have a shower in the morning, there won't be enough hot water to run a bath for the rest of that day.
It seems as if it isn't heating water during the day at all.
Has anyone had experience with this kind of system? Any advice at all??
Thanks in advance.

ariba10

Some immersion heaters have two switches that are.

1 for a long element, to heat the full cylinder and 2. for a short element that only heats the top half of the cylinder.

har0ld

It may be that your "off peak" element has given up the ghost. This would mean that you are only using the peak heating element, which will only heat the top of your cylinder. You shouldn't really need to use the peak element except in cases of high demand!
Elements are fairly easy to replace and not that expensive - however sometimes they can be a bit corroded and then you do have issues - unless you are confident with your plumbing I would get in a professional.
Hope this helps

pinkteapot

First thing to do is test the system. I used to have an Economy 7 system as well, with on and off peak switches for the immersion heater. I left the off peak switch on permanently (which would heat the water for the 7 hours overnight). I did however need to use the on-peak switch to 'top it up' before running a bath. A bath uses a full tank of water.

Try running a bath first thing in the morning after the hot water has been on overnight, before you've used any water for anything else. You should be able to get a full, hot bath out of it. If so, the off-peak element is probably working.

Next, leave the off-peak switch off for a night so the water is cold in the morning. Then try using the on-peak switch for a couple of hours. If the water gets hot, that's working too.

As I said, a bath holds a crazy amount of water and does need a full tank of hot water. I used to use the off-peak only which was sufficient for showering, washing up etc the following day. I did however used to put the on-peak switch on for an hour at least before running a bath, or there wasn't enough hot water. A domestic hot water tank is often 30-50 gallons (140-220 litres). A bath-tub can easily be 200 litres in size. Therefore, if you've showered and used other hot water already, the bath will consist of the remains of the hot water and some cold water which has refilled the tank.

ormus

a twin immersion heater cylinder.
its probably the top one thats gone west.