Shower running hot and cold

[mattoakes]

Hi,

We have a shower which runs directly from a mixer tap in our bath. In order to get the hot water to fire up from the combi boiler, you have to put it all the way to hot. Then, you can turn the lever to add some cold. After a few minutes it then goes cold and you have to turn the tap all the way to hot for the hot water to kick in again.

This doesn't happen with any other taps and it doesn't happen to the shower outlet to the mixer when a shower hose and head is not attached. It's only when a shower head and hose is attached to the mixer. I've tried a new hose and head and this hasn't made any difference. I've also tried adding and releasing pressure from the boiler with no difference.

Does anybody have any idea what the problem might be? Is it likely to be the boiler or the mixer tap? Any advice before I go spending money (inevitably on the wrong thing!) would be greatly appreciated!

Thanks,

Matt

 

[picasso]

It could be the shower head is too restrictive, try a bigger shower head .

 

[Agile]

Or clean the holes!

Try turning the boiler DHW temp control down!

Tony

 

[Whitespirit66]

Also, adding and releasing pressure from the boiler won't achieve anything. As you've discovered.

Make sure it's approx 1.2 BAR, measured with system cold, and your CH will be hunky dory.

 

[duffin]

get the biggest bore hose you can and a large headed shower. is it possible to turn the hot water temp down on your boiler? if so try that too.