Why is my mixer shower always cold?

[leothetiler]

Moved into our house a couple of years ago, and for some reason the shower in the en-suite has always been cold, but have no idea why.

The house was only built 5 years ago, so it is not that old and it just takes the water from the hot water tank so cannot see how anything can really go wrong.

People have suggested it may be limescale causing a blockage or an air block in the hot water pipe.

Any thoughts would be appreciated. Would it help just replacing the mixer or do you think it may be something more fundamental like not enough hot water pressure?

Getting very fed up with a cold shower in the mornings.

[leothetiler]

Thanks for all the useful input!

[leothetiler]

I should have said the hot comes from the hot water tank and the cold from the cold supply. Does not use a combi to heat the hot water.

[leothetiler]

rsv gone! said:

Thermostatic showers can scale up over time and if they're always left on one temperature then the gubbins inside can stop moving so freely.

Whilst it is running, try moving the temperature from lowest to highest a few times.

I have just tried that and there is a definite improvement! If you touch the mixer where the water comes out the wall it is boiling, but it just seems that it is not making its way to the shower head. Thanks for the advice, sounds like it is just a bit blocked up.

[leothetiler]

Ferg said:

It's likely to be the thermostatic cartridge not moving due to scale. Take it apart and clean the surfaces that the 'o'-ring slides on with one of those plastic scourers. Make sure you clean any scale from the cartridge itself and then grease it with silicon grease.

Thanks for the advice, will give it a go. I have looked in the loft above the shower and I cannot find the isolater for the hot and cold. How do I stop the water so I dont get soaked when I take the shower off?