5
Combi HP thermostatic mixer shower
packages with a cold take off after the pressure
reducing valve to the cylinder.
The layout and sizing of pipework must be such
that nominally equal inlet supply pressures are
achieved and the effects of other draw-offs are
minimised.
d) Mains pressurised thermal store
(fig.5)
Packages of this type, fitted with a tempering
valve (blender valve) can be used. A drop tight
pressure reducing valve MUST be fitted if the
supply pressures exceed 5 bar maintained.
An expansion vessel (shown in fig.5) MUST be
fitted, and regularly maintained, to make sure
the unit is not damaged by excess pressures. This
may already be installed externally or internally
within the thermal store (check with thermal store
manufacturer).
The layout and sizing of pipework MUST be such
that nominally equal inlet supply pressures are
achieved and the effects of other draw-offs are
minimised.
T00223
Service
valves
Balanced cold
mains supply
Cold mains supply
Mixer
shower
Expansion
vessel
Pressure
reducing valve
Pressure
reducing valve
Stop tap
Unvented
hot water
storage unit
Safety devices
not shown
Fig.4 diagrammatic view (not to scale)
Blender
valve
Flow
Cold mains supply
Hot
water
Stop tap
Expansion
vessel
Pressure
reducing valve
Return
Service
valves
Mixer valve
Boiler
T00224
Fig.5 diagrammatic view (not to scale)
