On 10/03/2017 11:56, AnthonyL wrote:

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

That may help, but alone but may not solve all the problems.

You really need mains (or similar) pressure feed on both hot and cold,
and then either a thermostatic shower or at least a pressure balanced one.

If there is a separate identifiable cold feed to the bath, then by all
means connect it to the cold main.

As to solving other problems - much depends on what the actual issues
are - there are a number of ways that combi fed showers can not perform
to expectations.


--
Cheers,

John.

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