hot water cooling down by evening

[barapapa]

this may be a bit tricky to explain, but our hot water (in the tank) seems to cool during the day, so by the evening we don't have any left. The tank seems to be insulated-it isn't just a metal tank IYSWIM- and the airing cupboard isn't hot like I would expect it to be if heat was escaping during the day. Any ideas? I know the water isn't running out- we have enough water in morning for 2 showers, but if we only have one shower in morning, there isn't enough hot water for another shower in evening. The hot water tank in question only supplies our bathroom. any help gratefully recieved. I don't know if it makes any difference but we have a digital shower.

what colour is your hot water cylinder? Please describe the insulation.

how is it heated?

Are there copper pipes around and above it; are they hot, are they insulated?

well PigletJohn- I am at work, but I know it is blue. It runs off economy 7 electricity. I have someone checking on the pipes around it. is super frustrating not to even have water hot enough to wash my face with at night!

does the cold water in your shower (or any other mixer taps) come out at mains pressure, unlike the hot, which is low pressure?

okay-apologies for lapse- tank is actually green and only one copper pipe going in center of the top of the tank, I think this is the hot water pipe and is not insulated. With regards to pressure- neither is at mains pressure- thanks

green is almost as good as blue

If your cylinder is heated only by an immersion heater, and has no facility for a gas boiler, then it will have only two pipes going into it; a cold feed at the bottom and a hot out at the top. The top one should bend horizontal for a foot or so before it runs upwards to the loft tank, and downwards for the hot taps.

The pipe coming out of the top should be warm for a foot or two, otherwise, when you have not run any hot water for an hour or more, they should all be at room temperature.

Is the pipe going upwards to the loft, hot all the way? Is the pipe going down towards the taps icy cold? Is the cold feed icy cold?

Can you see bare copper on any part of the cylinder?

have you got a bathroom or sink that's a long way from the cylinder? Is there an electric pump on any of the pipes?

can you get at the cold tank in the loft? has it been overflowing or dripping outside?

p.s.

have you got a Ceramic Disk mixer tap in the kitchen or elsewhere, perhaps with quarter-turn knobs or a joystick?

Good morning- I need to check temp of pipes, but I can't see any copper on the cylinder. There are 2 sinks downstairs from the tank, which are used very infrequently for hot water (less than once a week). I don't know if the tap in the bathroom is a ceramic disk one- but it is a joystick style. The taps downstairs aren't mixer taps (if I recall correctly- will confirm).

pipes seem right temp- cold ones are cold, and hot ones are room temp- any ideas anyone?

when you have not used any water for an hour or more, the pipes should not be "hot" and "cold," they should be at room temperature.

With no water being used there should be no water flow through the pipes so nothing to make them hot or cold and their temperature will equalise to their surroundings.

If in fact they are hot and cold, then you have flow through the pipes, therefore the water is being used, therefore the hot water will run out.

thanks for this PigletJohn- is much appreciated. need to investigate these pipes further- will monitor over weekend- think I need to check them around mid-day when not been used for a while-