Pressure Test Point
Sealing Screw
OUT
MIN | Gas Valve |
|
Fig. 48
Plastic
Protection
Cap
Modulator 
Wire
Maximum Rate
Adjustment Nut
Minimum Rate
Adjustment Nut
Fig. 49 NOTE: Gas Valve Electrical
Plug/Igniter not shown for clarity.
2
3
0 | 4 |
bar
Selector Switch
Pressure Gauge
Fig. 50
| 2 |
Reset |
|
1 | 3 |
0 | 4 |
| bar |
Power On 
Neon | Central Heating | Hot Water |
| ||
| Temperature Control | Temperature Control |
Fig. 51
11.0 Commissioning the Boiler
11.2Checking the Burner Pressure
1.Turn on the gas and electrical supplies to the boiler and ensure that all external controls are calling for heat.
2.Set the temperature controls to maximum and the selector switch to the Off position (Fig. 51).
3.Slacken the pressure test point sealing screw on the gas valve and connect a pressure gauge (Fig. 48).
4.Undo the screws securing the inner door panel. Lift the panel slightly to disengage it from the studs on top of the case.
5.Turn the selector switch fully anticlockwise against the spring pressure to the reset position and hold for 2 seconds to reset the boiler (Fig. 51).
6.Turn the selector switch to the Cental Heating and
Domestic Hot Water position (
). The power On neon (
) will illuminate (Fig. 51).
7.Turn a hot water tap on to give a flow rate of at least 10l/min.
8.The pressure should be :-
NG 12.1mbar
Propane 32.3mbar
If not, check that the gas supply pressure is correct (Natural Gas 20mbar, and Propane 37mbar).
9.The pressure can be adjusted if required.
10.To check and set minimum pressure first remove one of the modulator wires.
Adjusting the Pressure (Fig 49)
11.Remove the plastic protection cap from the pressure adjustment nuts on the valve.
12.The smaller nut (5mm) adjusts minimum pressure and the larger nut (8mm) maximum pressure.
13.Using a suitable spanner adjust the relevant nut until the correct pressure is achieved.
14.Once the pressure has been set turn the boiler off and disconnect the pressure gauge.
15.Tighten the pressure test screw and refit the modulator to the valve. Reassemble in reverse order.
© Baxi Heating UK Ltd 2007 | 33 |
