Baxi Barcelona Installation And Servicing Instructions page 11

6.0 System Details – page 11
Fig 11
Table 1
Where a vessel of the calculated size is not obtainable
then the next available larger size should be used.
NOTE
6.7 Sealed Systems (Fig. 11)
1. SAFETY VALVE - A safety valve complying with the
requirements of BS 6750 Part 1 must be fitted close to
the boiler on the flow pipe by means of a horizontal or
vertically upward connection with no intervening valve
or restrictions and should be positioned to facilitate
testing. The valve should be pre-set and non-adjustable
to operate at a pressure of 3 bar (45 lbf/in²). It must be
arranged to discharge any water or steam through a
pipe to a safe outlet position.
2. PRESSURE GAUGE - A pressure gauge of minimum
range 0-4 bar (0-60 lbf/in²) with a fill pressure indicator
must be fitted to the system, preferably at the same
point as the expansion vessel in an easily visible
position.
3. EXPANSION VESSEL - An expansion vessel
complying with the requirements of BS 4814 must be
fitted to the system by means of a connection close to
the inlet side of the circulating pump in accordance with
the manufacturers instructions, the connecting pipe
being unrestricted and not less than 15mm (½ in)
nominal size. The volume of the vessel should be
suitable for the system water content and the nitrogen
or air charge pressure should not be less than the
system static head (See Table. 1).
Further details of sealed system design can be
obtained from BS 5449 and the British Gas publication
entitled Specifications for Domestic Wet Central
Heating Systems'.
4. FILLING POINT - A filling point and an approved stop
valve to BS 1010 must be fitted at low level and the
method used for filling the system should be approved
by the local water undertaking. For further details see
BS 6798.
5. MAKE UP SYSTEM - A method of replacing water lost
from the system should be provided either by means of
a make up vessel of not more than 3 litres (5 pints)
capacity, mounted above the highest point of the
system, or by re-pressurisation of the system.
6. VENTING - A method of venting the system during
filling and commissioning must be provided by fining
automatic air vents or by venting manually.
7. HOT WATER STORAGE - The hot water storage
vessel must be of the indirect coil type. All components
used in the system must be suitable for operation at
110ºC (230ºF) and at the pressure allowed by the
safety valve.