36
10-2
Extra Procedures for System Boilers
10-2.1 Expansion Vessel Pressure
Check that the expansion vessel is adequate for the system as follows:-
Operate the system at normal temperature (80°C) with all radiators on and hot water on.
The system pressure will rise above the cold fill pressure.
If the pressure rises more than 0.5 bar then an additional expansion vessel will be
required. Part IBS7074 Part 1 includes information on additional expansion vessel
requirements.
10-2.2 Check Pressure Relief Valve
To check operation of the pressure relief valve, temporarily increase the system pressure.
The valve should operate when the pressure increases to 3 bar ± 10%.
Reduce the pressure on completion by manually operating the pressure relief valve.
10-3
Extra Procedures for Combi Boilers
2
bar
1
3
4
0
Record Cold Fill Pressure
✍
10-1.5 Conventional Flue and Chimney
Check that the chimney has been lined/insulated to prevent condensation, is of the
correct size and has no obstructions to restrict the flow of gases.
Check that the flue is of the same diameter for its entire length. A flue that steps from
one size to another will affect the draw of air resulting in inefficient Burner operation or
Burner malfunction.
Check that a suitable round terracotta pot has been used and that the draught stabiliser is
working freely, if fitted.
Check that the flexible air duct is correctly fitted from the adaptor to the Burner.
Check that the test point bolt is fitted in the adaptor.
10-1.6 Balanced Flues
Check all balanced flues for their positioning and that the installation complies with
details in this manual.
Check that the flexible air duct is correctly fitted from the balanced flue to the Burner.
Check that the test point bolt is fitted in the adaptor.
10-1.7 Electrical
Check that the wiring circuit is correctly fused and giving the appropriate supply to the
Burner.
Check lockout function of the control box by removing the photoresistor from the Burner
and obscuring light from it.
Check the operation of the limit stat or temperature limiter by temporarily removing the
phial of the control stat from its pocket.
COMMISSIONING 10
COMMISSIONING 10
COMMISSIONING 10
COMMISSIONING 10
COMMISSIONING 10
10-3.1 Expansion Vessel Pressure
Check that the expansion vessel is adequate for the system as follows:-
Operate the system at normal temperature (80°C) with all radiators on and hot water on.
The system pressure will rise above the cold fill pressure.
If the pressure rises more than 0.5 Bar then an additional expansion vessel will be
required. Part IBS7074 Part 1 includes information on additional expansion vessel
requirements.
10
10
10
10
10
0
1
2
3
4
5
6
0
20
40
60
80
bar
psi
