Baxi Solo 2 PF Installation And Servicing Instruction page 9

3.0 System Details – Page 9
Method of determining minimum value of expansion vessel
volume for sealed systems using Baxi Boilers
Table 1
Where a vessel of the calculated size is not obtainable then the
next available larger size should be used
NOTE
3.6 Sealed Systems (Fig. 8)
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/in
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/in
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 pre-pressurisation of the system.
6. VENTING - A method of venting the system during
filling and commissioning must be provided by fitting
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.
9
2
). It must be
2
) with a fill pressure indicator