Hot Water issue

[roonies]

Hi, we have a Gas open vented heating system with a large copper insulated hot water tank. The tank is 450 x 1500mm , think around 200 litres and around 15 years old. Although we have an immersion heater fitted it is not wired up so the water is only heated via the gas boiler.

The problem we have is we have a pumped power shower and when used the hot water doesn't last very long at all, the shower isn't set to very hot either. If we run a bath with one fill the hot water is all gone also.

The temperature on the tank thermostat ( which is only 6 months old ) is set to 80 and the boiler is set to heat the water both morning ( around 2 1/2 hours ) and evening ( around 6 hours )

Our water is fairly heavy and we get quite a bit of lime scale around taps etc that we have to clean.

I am thinking the issue may be with the hot water coil in the tank and it possibly being scaled up but after other views to see if I'm on the right track.

If so I presume the tank will need to be replaced. If that's on the cards are we better off getting a smaller tank where the coil is a similar size to the tank as the one we have the coil is around a third the size of the tank.

Any help will be appreciated.

 

[picasso]

I often find that people turn the boiler stat down and dont realise it affects the hot water, how high is the stat on your boiler.

 

[ServiceNumpty]

What size is the Cold Water Storage Tank, you'd be surprised how quickly a power shower will exhaust the hot water store.

 

[roonies]

Picasso - just checked the boiler and there are no numbers on the stat but I would say it's around a third up from minimum. Do you think I should turn it up ?

Michael5041 - we have two very large water cold water tanks in the loft linked in series. I have never seem them drop more than about a third. Each tank has it's own draw off which links into a single 22mm pipe to keep them balanced although I can isolate a tank via a stop valve if needed.

 

[roonies]

One other note, not sure if this will help. When the shower is first turned on its is really quite hot, even when set to 6 out of 15. But after around a min it cools off and you tend to turn it up another notch or two. I was wondering if maybe the thermostat on the shower mixer if faulty and it's using to much hot water... Or is that how a pumped power shower normally works ?

 

[St0rmer66]

Definitely turn up the boiler thermostat. Try more like 2/3 of the way up. You are trying to heat the cylinder to 80 degrees; which is too high and unattainable anyway, so may as well turn it it down to stop the pump and boiler running the whole time the timer is on for hw; using water in the coil (from the boiler) at something like 50 degrees. I don't think I need to explain to you why that isn't possible! Try cylinder thermostat at 65 and boiler stat as I said and see how you get on... Cylinder may well be scaled up but this should at least give you more than you have currently.

 

[Agile]

If you want us to tell you what is wrong then we need proper scientific information!

1. What height is the cyl stat fitted at?

2. When you feel the cyl how much of it is hot?

3. What is make and model of boiler? ( Profile? )

4. What is the flow rate from your shower? Answer in litres per minute!


The FAQ on this site will give you any help you need to find these answers.

I would also expect your cylinder is only a little more than 100 litres and not 200 litres.

Tony

 

[blackfriars]

hi, what is the make of your shower??
is your heating zoned for independent hot water or heating
your tank stat should be set approx 60 c & placed approx 1/3 from bottom of cylinder
there is a difference between a pumped and powered shower by flow rates
in most cases a standard cylinder will take approx 20+ mins to reheat to 60 c.
most people will have finished their shower in 10 mins or less