Shower Running Cold (hidden unit)

[Hoddo]

My shower is running cold. Water pressure is fine and there is hot water in the rest of bathroom.

I can't access the main shower unit, it is hidden behind a tiled wall. There are wall mounted remotes to adjust flow and temperature.

Before I call on the services of an expensive plumber, can anyone recommend any solutions?

[Hoddo]

Nope. A smooth tiled wall.

If I could access the shower what may be causing the problem?

[Hoddo]

Having a really hard time removing the temperature knob. It is clearly being held on by a single screw, however this screw has a flush head. Any advice how I remove it? See pics.

[Hoddo]

elanfan said:

I reckon that is just a cover you just need to get something in there to pop it off.

Cover your plughole or it will end up down there!!

Grand. I will get a knife under it this evening and see what's underneath.

[Hoddo]

gtidriver said:

Did you get the cap off or are you still at casualty with a knife stuck through your hand

Cap came off. Inside there was a headless screw which I removed with an allen key. Once this was removed I was still not able to move anything, despite considerable force. Should the temperature knob unscrew or just pull of at this stage.

Upon further inspection there was nothing else in the hole which could be unscrewed or removed.

Getting rather frustrated as I am clearly missing something simple here.

[Hoddo]

Thanks all. Will attack it tomorrow evening and update.

[Hoddo]

Doing my nut in. Manage to remove the outer temperature knob but have been unable to remove the larger knob that controls water on/off.

Any ideas? No visible holes for an allen key to go. Tried brute force to pull it off and tried turning it but neither did the trick, either that's wrong or I'm weak.

[Hoddo]

MajorProblem said:

What about that bloody great e clip on the main shaft?

I'm a DIY simpleton.

E clip?

[Hoddo]

Googled it.

Got my pliars and will give it a go now

[Hoddo]

I replaced the cartridge and the shower now produces lovely hot water, however, the shower does not appear to trigger the boiler.

When the shower is turned on it runs cold until the on-suite sink hot tap has been run for 10 seconds, after this the shower will run hot until you either touch the temperature knob or turn the flow off. Its as if the boiler doesn't know the shower is there and demanding hot water.

Any idea why it may not be triggering the boiler?