Hot water runs cold when taps are turned on full

[david316]

Hi,

When the hot water taps are turned on full the water runs cold. This is the case for all hot water taps/shower in the house.

At the moment you have to find 'the sweet spot' by half turning the tap on so that it remains hot.

What suggestions would you make to remedy this problem. I want to be able to turn the tap on full and hot water come out.

My first thoughts are slowing the hot water pressure down but I dont have a clue how to do this.

Thanks for your answers

 

[45yearsagasman]

How about telling us a bit more on the system and equipment installed. You've told nothing except your symptoms

 

[david316]

Suppose that would help!

I have a Combi Boiler. (I dont know the exact model but can verify this later when I get home)

What else do you need to know?

 

[Burnerman]

Your combi will only really supply one hot tap or shower at a time with any significant volume of hot water......is this a new symptom you're experiencing?
John

 

[david316]

Hi John, Thanks for the reply.

No its always been an issue. Even if I run one tap on its own it runs cold if I turn it all the way on. I have to turn the tap half way to get hot water out of it.

Hope this makes sense

 

[Burnerman]

It makes complete sense, and I would presume the problem is worse in the winter when the incoming water is very cold.
You may be able to increase the boiler temperature by using the thermostat - if there is one.
Just check that the radiators don't start to get warm, even though the heating is off, will you?
John

 

[david316]

Ill check what level the thermostat is at tonight.

My thinking was that the water pressure is too high and the boiler cant keep up that is why it goes cold. I thought the solution might be turn the water pressure down so that the boiler can keep up?

 

[Agile]

You may just have high mains pressure.

The boiler will only give about 9 litres per minute of hot water. Take any more and it will become cooler.

Measure the flow rate in litres per minute and tell us the boiler make and model.

Tony

 

[gigz]

With the heating switched off, turn a hot tap on and feel the heating flow pipe under the boiler, usually the far left pipe but without knowing the boiler can't tell you which one it is for definate. It shouldn't get hot.