Worcester 350 Combi User Manual

7.6 System Design Pressure. The maximum system design pres·
sure is 1.5 bar (21.5lb /in.
2
).
If the pressure is greater than 2.6 bar when operating at maxi·
mum system temperature, then an extra expansion vessel must
be fitted as close as possible to the central heating return connec·
tion.
If the expansion vessel within the appliance fails it must be
replaced with the designated spare part. See Section 14.4 and
Se ction 15.
7. 7 Filling. See
Fig . 6. The filling point must be at low level.
7.8
Make· Up. See Fig . 6. Water lost from the system must be
replaced. Refer to BS 7074, Part 1. The connection must be made
in
the central heating return as close as possible to the appliance.
7.9 Venting. The system and the appliance must be properly
vented. Repeated venting reduces the amount of water in the
sys·
tern. It is essential that this water is replaced and the system
pressure maintained. The reason f or the need to repeatedly vent
Fig. 5. Sealed primary water system.
0 Ma ke-up bott le
I
r-44----.J
1 No n- return va l ve
l
Appliance casing
I
I
I
I
I
E
Ex pansion ves se l
(extr a}
Do m estic ho t water
flow regu lato r
Domest ic hot wate r
D
omestic co ld wate r
Br itish standard
stop valve .
F
ixed spi n dle
type.
Low wa te r
pressure sw i tch
I
I
i
Central h eating return
Ce n tra l heat i ng flo w
Fig. 6. System filling and make-up.
Heating return
Worcester Combi - Fill System
Non return Non return
valve valv e
+- +-
~Hose unionl
.,. ___ """'·-'P'V4 ... - -=== =u ;r: : • t ~ 4
ll ll Stop cock
11 II
'~'.:=== ·.:' ' '
Test cock
Temporary hose
8
the system (usually a leak) must be rectified.
7 .1 0 Water Mains Connection. There must be no connection to
the mains without the authority of the local Water Company.
7.11 By -Pass. An adjustable system by·pass is fitted to the appli·
ance.
7.12 Pump . The pump on the central heating sy stem is set at
maximum and must not be adjusted.
7. 1 3 Connections.
Connections in the system must resist a pres·
sure of up to 3 bar.
7.14 Valves. Radiator valves must conform to BS 2767(10): 1972.
Other valves used should conform to
the requirements of BS 1010.
7.15 L ow Water Pressure Switch. The switch will stop the appli·
ance if the system pressure falls below 0.5 bar (7.5 lb ./ in.
2
). Th is
will be indicated by a red light on the facia. The cause of the drop
in pressure (such as a leak
in the system) must be investigated and
rectified.
Heat ing return
A drain cock shou ld
be fitted at the l owest
point off t he heat i ng
ci r cui t and the ap p lian ce
R
adiato r va l ve
Auto
air vent
.. , ..... 1-- Fill po int
Heating return
300 mm ( 12 in) min.
above the highes t
point of the s ys tem .

Worcester 350 Combi Specifications

General

Brand	Worcester
Model	350 Combi
Category	Boiler
Language	English