Sealed Systems; Pressure Relief Valve; Pressure Gauge; Expansion Vessel - Vaillant VCW 2O Instructions For Installation And Servicing

5.7 Sealed systems
Sealed systems do not require leed and
exDansion cisterns, open vents etc' only gooo
ouitiW raOiator valve's and fittings should be
Jsed in order to prevent excessive detrlmenlal
topping-uP.
5.7.1 Pressure lelief valve
This is required on all sealed systems and is
connected'as shown in 4'3.4'
5.7.2 Pressure gauge
This is factory fitted to the boiler and shows the
pressure in the Primary circuit.
5.7.3 Expansion vessel
A 1 5 litres expansion vessel is incorporated into
ihe combi b6iler suitable for a sealed heating-
iuit".
with a maximum water contents of
260 litres (57.2 lmP. galls')
lf the nominal capacity of the built-in expansion
vessel is not sufficient for the heating sys,tem.
itor-instance in case of modernization of old
iioen Jvstems) an additional expansion ve-ssel
cin Oe instatt6d to the side connection of the
ieturn service cock in connection with the
pressure relief valve.
5.7.4 Filling and make uP
The svstem should be filled with water via a
seoar6te lilling point fitted at a convenientpoint
on' the neati-nb circuit. Where local Water
Authority Regulation allows, a temporary
connection to-the mains may b,e used' The
connection must be removecl when lllllng ls
completed. Where local Water Authority
Reqirlation does not allow temporary
corinection, a sealed system filler pump with
break tank must be used. The heating system
witt not be filled automatically from the
domestic side.
ln principle, sealed systems do not require
waier mat<e-up faciliti6s, but experience has
shown that some make-up may be necessary'
Methods of filling sealed systems are given in
appendix A of BS 5376:2.
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5.7.5 Pipework
All oioework shall be securely supported, shall
run'n'eatly and be concealed where possible'