Combi Boiler want power shower Drainage and wastage systems and plumbing help, advice and answers

[monalisasmiler]

Is there anyway we can increase the power to our showers with our current system? We previously had two tanks one in cylinder and one in loft but were recommended a combi boiler which we now have we have two showers but the power is not very good at all and would like to increase some way if this is possible.

[plumbbob]

A modern combi boiler should be able to give a shower better than a traditional power shower. If it doesn't, either the boiler has insufficient capacity or the incoming water main is old and furred up.

With an average power shower, you would be experiencing about 1.5 bar pressure, with a mains fed shower this is going to be closer to 3 bar. Basically twice as much! (Well ought to be.)

However, no domestic combi boiler will supply two mixer showers simultaneously.

[monalisasmiler]

Thanks Bob, our bathroom has just been fitted and our boiler is 5 years old, is there a way of determining what the problem is or how to increase the power?

Thanks.

[plumbbob]

I don't really know where to begin with advice because you haven't offered enough information to draw any conclusion.

What's the cold water pressure like at the kitchen tap for starters?

[monalisasmiler]

We have a boiler Glow Worm 35 ci our shower is Thermostatic Mixing Valve shower. Water pressure outside 3 bar but I seem to remember about 10 years ago the pressure downstairs when you turned the tap in the kitchen the water used to burst out of the downstairs tap so a plumber put something on to regulate this.

Sorry for sounding so unknowledgeable and thank you so much for your replies.

Very much appreciated.

Mona

[plumbbob]

Water pressure outside 3 bar but I seem to remember about 10 years ago the pressure downstairs when you turned the tap in the kitchen the water used to burst out of the downstairs tap so a plumber put something on to regulate this.

In theory you have the correct set up to provide a good shower. Of course, I am assuming the Glow Worm is working properly.

The most likely explanation is the water flow from the main is being restricted in some way which is reducing the shower's performance. It might be the incoming stop tap has been left only partially open, a trick often used to stop the splashing from taps.

It might be a plumber has fitted a prv (pressure reducing valve) and this may be where your problem lies. Maybe your shower installer has fitted prv's in the mixer valve that are not required.