Potterton Prorile Prima 30e Installation And Servicing Instructions page 9

TECHNICAL DATA - Page 9
If the system is extended, the expansion vessel volume may
have to be increased unless previous provision has been
made for the extension. Where a vessel of the calculated size
is not available, the next available larger size should be used.
The boiler flow temperature is controlled at approximately
0
82 C.
The vessel size can now be determined from the following
table where V=System volume in litres.
Vessel Charge Pressure(bar)
Initial System Pressure (bar)
Expansion Vessel Volume (litres)
Cylinder
The hot water cylinder must be an indirect coil type or a direct
cylinder fitted with an immersion calorifier suitable for
operating at a gauge pressure of 0.3 bar (Slbf/in
safety valve setting. Single feed indirect cylinders are not
suitable for sealed systems.
FIG. 6 OPEN VENTED FULLY PUMPED SYSTEM FITTED
WITH A COMBINED FEED AND VENT
Method of Make-Up
Provision shall be made for replacing water loss from the
system either :-
i)
ii)
0.5 1.0
1.0 1.0 Mains Connection
There shall be no connection to the mains water supply or to
V x 0.11 V x 0.087
the water storage tank which supplies domestic water even
through a non-return valve, without the approval of the local
Water Authority.
2 Filling Point
) in excess of
The system shall be fitted with a filling point at low level which
incorporates a stop valve to BS1 010 and a double check
valve (approved by the National Water Council) to be fitted in
this order from the system mains, Refer to FIG. 7. Method 1.
from a make-up vessel or tank mounted in a position
higher than the top point of the system, and connected
through a non-return valve to the system on the return
side of hot water cylinder or the return side of all heat
emitters.
or
where access to a make-up vessel would be difficult by
using the mains top up method or a remote automatic
pressurisation and make-up unit as illustrated in FIG. 7
METHODS 1 and 2.