Typical Suitable
Installations
14
High-Pressure Unvented Mains
Pressure Cylinder Installation
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 500kPa (5 bar).
The drop tight pressure reducing valve
MUST be set at the same value as the
unvented package pressure reducing
valve.
A non-return valve MUST be fitted
before the stop tap (Fig 3).
Note: An additional expansion vessel (Fig
3) 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.
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.
Fig 3 High-pressure system
installation
–
Unvented mains
pressure cylinders
Fig 3
Mixer Unit
Safety devices
not shown
Circulation
Loop
Service
valves
Kit
Unvented
hot
water
storage unit
Controller
Unit
Pressure
reducing valves
Expansion
vessel
Balanced cold mains supply
Non-Return Valve
Stop tap
Cold mains supply
