On Fri, 10 Mar 2017 11:56:14 +0000, AnthonyL wrote:

Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years ago.

The shower is on the first floor. The tap is one of those old fashioned
two-into-one with a plunger to change the destination from down into the
bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no separate
control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

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.

Any thoughts?

As far as I am aware you should never mix tank and mains pressure at a
shower. Unless there is a non-return valve on the cold this looks a very
dodgy set up because you are connecting mains pressure to tank pressure
through the shower head.

I assume that there is still a hot water tank, otherwise why the header
tank in the loft? That is, the boiler is working as both a combi (directly
heating mains hot) and a system boiler (heating some kind of hot water
store).

Two alternative solutions; install a pump to take hot water from the tank
and cold water from the loft, or plumb in mains cold to the shower.

In either case the shower should be a high pressure model for mains
pressure as opposed to a low pressure model for gravity fed.

It does sound like a plumbing bodge from what you report.

Cheers


Dave R


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AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

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