Vertical bar mixer shower
5
Instantaneous gas-heated systems,
e.g. combination boilers (fig.4)
The shower control MUST be installed with a
multi-point gas water heater or combination
boiler of a fully modulating design (i.e.
to maintain relatively stable hot water
temperatures).
A drop tight pressure reducing valve MUST
be fitted if the supply pressures exceed 5 bar
running.
An expansion vessel MAY be fitted, and regularly
maintained, to prevent the shower mixer
being damaged by excess pressures. This may
already be installed within the boiler (check with
manufacturer) and is in addition to the normally
larger central heating expansion vessel.
Unvented mains pressure systems (fig.5)
The shower control can be installed with an
unvented, stored hot water cylinder.
For systems with no cold water take off after the
appliance reducing valve, it will be necessary to
fit an additional drop tight pressure-reducing
valve when the mains pressure is over 5 bar. The
drop tight pressure reducing valve must be set at
the same value as the unvented package pressure
reducing valve.
Note: An additional expansion vessel may be
required if a second pressure-reducing valve is
installed. This does not apply to packages with a
cold take off after the pressure-reducing valve to
the cylinder.
*Fig.4
*(diagrammatic view – not to scale)
*Fig.5
*(diagrammatic view – not to scale)
CH flow
Cold
mains
supply
Hot water
CH return
Service
valves
Mixer
Stop
tap
Expansion
vessel
Pressure
reducing valve
Combination
boiler
Kit