New shower head problem

[Greenrememberedhills]

I've just replaced a tatty shower head with a new one, which took seconds to screw on. It has a restrictor option, and several types of water jet.

It runs cold, despite the other taps running hot.

The shower is a walk in shower on a mains gas supply. It normally runs very powerfully, and has a storage cylinder in the loft.

It runs cold, de

Sorry, posted too soon.
Is anyone able to suggest what's wrong? Thank you.

Have you just put a new head on the shower hose then? Is it a thermostatic shower valve?

Perhaps you've knocked something and turned the water temperature down.

Thanks for replying.

Yes, I've put a new shower head in the hose. It was easy to put in/on. I just unscrewed the old one off and screwed in the new. The old one was dented, and in any case there were no spray options and no water restrictor. The water restrictor was the key attraction of the new one, as before one could empty the cylinder tank in seconds, it being an extremely powerful shower.

The shower enclosure was there before we came, and it is a fixed brass Victorian lookalike one, with a thermostat valve tap on the riser/wall, which looks a bit like an old fashioned stopcock. It does regulate the temperature though. I did try turning it right round in either direction after I discovered the problem, but it didn't help.
.

aha

You say you have a hot water cylinder, supplied from a tank in the loft.

Go into your bathroom. Turn a hot tap on. Press your thumb over the spout. Can you stop the flow?

Now turn a cold tap on. Press your thumb over the spout. Can you stop the flow?

Hi Pigletjohn

Very glad you've turned up. The answer is no, without getting soaked!

no both, or no one?

No both. Cold v slightly stronger.

wrong answer

But why, Pigletjohn? What does it mean?

I've put the old tatty head back on and it's running hot fine.

The reason I chose this particular head when I swapped them was because the teens in this house can empty the tank in seconds having a shower. The pressure in it blows you off your feet. It means we always need to reheat the water for successive showers.

On the other hand that doesn't happen in our ensuite, which is more gentle.

I was expecting to hear that the cold pressure was higher than the hot.

What colour is your hot water cylinder?

What shape is the tank in the loft?

Have you got a pump?

Oh god. I don't know. I will look tomorrow. And thanks.

Ok.

I would upload the photos I just took, but I don't know how to.

Up in the loft there is

1. a cylinder with these sorts of details on it:

Cylinder Megaflo
Model CL 145
16 bar
Operating pressure 3 bar
145 litres
Pressure reducing valve must be fitted to all installed

1. A sort of rectangular separate boiler thing called a Halstead Eden Vb

3 a 'Red thing' on the wall which looked like a mini red orangey cylinders.

Does this help?

I also noticed totally separately an old header or storage tank which is really quite small and totally empty and dusty.

As you have a Megaflo I think it will be because the pressure into that is reduced, and the cold is still at mains pressure.

That would cause the cold water to overpower the hot in the mixer.

You could have a pressure reducing valve fitted to the cold pipe, or a pressure balancing valve fitted to the hot and cold pipes on their way to the mixer.

If you have several mixers in the house it might be simpler to reduce the pressure on the cold pipe.

Your Megalflo should be inspected and if necessary serviced annually, the person servicing the boiler can do it IF they have the extra qualification for unvented cylinders (ask first). In which case they will probably have encountered the problem before and will be able to suggest and fit the best option. If you mention you would like the shower flow reduced to avoid draining all the hot water there is probably a solution. Unqualified plumbers should not work on unvented cylinders.

P.s.

I bet your cylinder is white.

Thank you very much Pigletjohn. Yes I forgot to say that the cylinder is white.