What lesson can be learnt from this?

[Balenza]

Agile wrote

Thats the problem many need check valves but few people ever fit them!

The problem is incorrect installation.
With balanced supplies check valves are not needed.

 

[Agile]

The problem is incorrect installation.
With balanced supplies check valves are not needed.

Where does it say that in the Water Regulations?

 

[doitall]

The problem is incorrect installation.
With balanced supplies check valves are not needed.

Where does it say that in the Water Regulations?

It doesn't Tony.

The water regs clearly state the mix most take place in atmosphere or check valve must be fitted.

 

[Balenza]

The problem is incorrect installation.
With balanced supplies check valves are not needed.

Where does it say that in the Water Regulations?

It doesn't Tony.

The water regs clearly state the mix most take place in atmosphere or check valve must be fitted.

It also states -
The Water Supply Industry deems that the particular requirement of the Regulation will be met if their are no check valves on either "side" of the supplies to mixer taps where water mixes within the body and the supplies are on balanced pressures.

I realise this is a separate issue from a shower fitting due to the type of air gap required under the regulations but the principle is exactly the same other wise.

 

[chrishutt]

But supplies from a combi boiler are in practice not balanced. Although static pressures are equal once a hot outlet is running the dynamic hot pressure drops, sometimes hugely, leaving one with imbalanced pressures.