with integral strainer, expansion relief and check valve, factory fitted pressure
and temperature relief valve and expansion vessel. All of these components
must be included in the installation. The pressure settings on these
components are factory set and indicated on the top of the valve. Do not
break any seals or attempt to adjust any safety valve; to do so may impair
the safety of the installation and will invalidate the warranty.
It is recommended that the unit is installed according to these instructions.
Under no circumstances should the expansion relief valve be installed in an
inverted position as fouling of the seat caused by deposits may prevent it from
operating correctly.
Safety relief valve connections should not be used for any other purpose and
no valve should be fitted between the expansion relief valve and the storage
cylinder.
An isolating valve must be fitted to the cold water supply to the inlet manifold.
The Zip Varipoint is designed for use with a supply pressure up to 12 bar. For
supply pressures exceeding 12 bar an additional pressure reducing valve must
be fitted in the cold water supply to the unit.
Secondary Circulation
The Zip Varipoint is not recommended for use with secondary circulation
systems.
Discharge
The expansion relief and temperature and pressure relief valves should drain
via a tundish which should be installed in a visible location and away from any
electrical devices.
The discharge pipe from the tundish should terminate in a safe place where
there is no risk to persons in the vicinity of the discharge, be of metal and:
a) Be at least one pipe size larger than the nominal outlet size of the safety
device unless its total equivalent hydraulic resistance exceeds that of a
straight pipe 9m long. Discharge pipes between 9m and 18m equivalent
resistance length should be at least 2 sizes larger than the nominal outlet
size of the safety device, between 18 and 27m at least 3 sizes larger, and
so on. Bends must be taken into account in calculating the flow resistance.
See diagram of typical discharge pipe arrangement on page 8 and table for
sizing copper discharge pipe on page 9.
b) Have a vertical section of pipe at least 300mm long, below the tundish
before any elbows or bends in the pipework.
c) Be installed with a continuous fall.
d) Have discharges visible at both the tundish and the final point of discharge
but where this is not possible or it is practically difficult there should be
clear visibility at one or other of these locations. Examples of acceptable
discharge arrangements are:
1. Ideally below a fixed grating and above the water seal in a trapped gully.
Zip Varipoint III Installation, Maintenance and User Instructions - August 2008 7
