Hot water runs out fast

[Fraz]

Hi,

I have recently moved into my first house and hence have now got to come to grips with central heating and hot water tanks.

The problem I have is that I only ever have enough hot water for two showers. The hot water tank is (from what I can tell) a normal size and has lagging. The shower is a power shower and uses quite a bit of water but I would expect cold water to enter the tank and get heated while the hot water is being used. The thermostat on the tank is set to 60C and when you run the hot water tank the water is very hot.

The pipes that run around the boiler and tank aren't insulated. The tank is downstairs in the kitchen and the surroundings are fairly warm.

Is this just the fact that my shower is using all the hot water too quickly or is/could there be a more sinister reason for my problem?

I really appreciate any help you can give, thanks,

Paul.

[ron]

You are using the water more quickly than it is being heated. My power shower does that as well.

[Lurch]

Sounds about right, the water in the tank is flowing out at a faster rate than at which it could be reheated on it's way through. Usually between 15-20 mins for a reheat time on a full tank, depending on what system you have. Could be longer if it's an older system, sounds like yours could be. It does all depend if the system has been set up properly to start with, I have seen instances of the boiler being turned down too low to be able to do anything in a reasonable time.

Is the HW turned on at the programmer, obviously if it's not then you'll get no more water until it comes on again. SJW

[IMM]

Paul,

It appears your cylinder is too small. This can be remedied by:

1. Fitting a larger cylinder.
2. Fitting a cylinder of the same size and with a quick recovery coli inside that take all of the boilers output (the boiler has to be on full temperature)

Or both of the above.

You could try this as an interim and see how it works:

a) Install a hot water blending valve on the cylinder hot water draw off to the taps (these are becoming mandatory soon anyhow). This ensures that water is at a tempertire that does scald. b) Raise the temperature of the boiler to full, and keep it on full at all times, and the cylinder temp to 75C. This store more hot water, yet only water at a lower temperature is at the taps. The shower mixer must be thermostatic. c) Lag all pipes around the cylinder.

This has the effect of making your cylinder larger by storing more hot water. If it does not fix the problem fully, then install a cylinder with high grade insulation and a quick recovery coil, not a part L cylinder, one with a "quick recovery coil" and the hot water blending valve.

Travis Perkins sell the Typhoon quick recovery coil cylinder, and quite cheap too.

and Screwfix sell the blending valves.

[BillR]

How cheap at TP? I'm interested in one of these but can't find 'em on those sites and the quick recovery one plumbworld has is bloody expensive, £250...

[IMM]

80 litre model is £99 inc VAT. This is equiv to a 114 litre part L. See the Albion site for comparisons. The 120 litre model is around £150-160, I think.

[IMM]

The one at Plumbworld, Albion Superduty, they is a mains fed cylinder. The superduty usually is not. I would check this out.

[Paul Boakes]

Is there a speed control on your shower pump? Could you adjust the speed downwards, to see if that improves things, without lowering the quality of your shower experience too much?

Regards Paul

[BillP]

I fitted a Gainsboro 12ltr in my own house. This had no flow control and the output was way more than necessary. I added a diode 1N4007 in series with the supply. Cut the output down to a very sensible rate and still more than adequate.

Billp

[derek]

Well if it works it works.

However, Not all electric motors intended for AC would tolerate that, which would result in the supply having a DC element with a strange waveform AC element added to it.

Wouldn't fitting a bypass around the pump with a ball valve to adjust the proportion of the pump output fed back to the input give a continuously variable usable output without taking liberties with the pump motor ?

DG

[BillP]

Yep works a treat.

Most power showers are built to a budget cheap DC motors in the middle of a bridge rectifier. This one runs half waved no probs.