Grant Spira Series - Sealed System

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6 Sealed Systems
All Grant Spira boilers are suitable for
use with sealed systems complying
with the requirements of BS EN
12828:2003, BS EN 12831:2003 ad BS
EN 14336:2004.
The system must be provided with the
following items:
• Diaphragm expansion vessel
complying with BS EN 13831:2007.
• Pressure gauge.
• Pressure relief (safety) valve.
• Approved method for filling the
system.
Expansion vessel
The expansion vessel can be fitted in
either the return or flow pipework in
any of the recommended positions as
shown in Figure 6-1. To reduce the
operating temperature of the expansion
vessel, position it below the pipe to
which it is connected.
The expansion vessel may be
positioned away from the system,
providing the connecting pipe is not
less than 13 mm diameter. If the
expansion vessel is connected via a
flexible hose, care must be taken to
ensure that the hose is not twisted.
Pressure Gauge
The pressure gauge must have an
operating range of 0 to 4 bar.
It must be located in an accessible place
next to the filling loop for the system.
Safety Valve
The safety valve (provided with the
boiler) is set to operate at 2.5bar. It
should be fitted in the flow pipework
near to the boiler.
The pipework between the safety valve
and boiler must be unrestricted, i.e.
no valves. The safety valve should be
connected to a discharge pipe which
will allow the discharge to be seen,
but cannot cause injury to persons or
damage to property.
Filling Loop
Provision should be made to replace
water lost from the system. This can
be done manually (where allowed by
the local water undertaking) using
an approved filling loop arrangement
incorporating a double check valve
assembly.
The filling loop must be isolated and
disconnected after filling the system.
Heating System
The maximum set point temperature for
the central heating water is 75°C. Refer
to Section 1.1.
Figure 6-1: Sealed heating system components
!
NOTE
Ensure that the expansion vessel
used is of sufficient size for the
system volume.
Refer to BS 7074:1:1989 or The
Domestic Heating Design Guide for
sizing the required vessel.
2
1
2 3
4
5 6
7
7
8
9
10
Static head of system
*
* 3 port valve (alternative to 2 zone valves)
6.1 Sealed System Requirements
1. Expansion vessel
2. Pressure gauge
3. Safety valve
4. Discharge
5. Filling loop
6. Double check valve
7. Automatic air vent
8. Thermostatic radiator valve
9. Automatic bypass valve
10. Drain tap