21
5.4 INITIAL LIGHTING - Refer to Fig. 24
1. Ensure that the gas and electrical supplies to the boiler are off and that the mains water inlet valve and the central heating
flow and return valves are open.
2. Turn on the gas and electrical supplies to the boiler.
3. Ensure all external controls are calling for heat.
If the optional Clock is fitted, refer to the User's instructions, set the time and ensure the Clock is in an 'on' mode.
4. Set the hot water and central heating thermostats to maximum.
5.5 CHECK THE BURNER PRESSURES - Figs. 25, 26
Turn the boiler off. Remove the two pressure test point screws at the top of the boiler and connect a differential pressure gauge
to P1 and P2 as shown in Fig 25. Check the differential burner pressures.
Hot water mode
1. Set the selector switch to
(DHW only).
2. The burner will light at the ignition rate and the burner pressure will increase to maximum.
3. The burner will stay at maximum output for approximately 3 minutes and then the burner pressure will decrease slowly to its
minimum, until the hot water store obtains a temperature of 65°C.
4. Check the burner pressures and that the burner goes out when the store is satisfied.
Note: The burner pressure settings have been factory set and do not require adjusting. If incorrect, check that the inlet gas
pressure is 20 mbar.
If the inlet gas pressure is not 20 mbar, either the pipework is too small or the gas supply to the house is insufficient, in which
case contact your gas supplier. If the differential burner pressures are still incorrect contact Alpha.
Central heating mode
1. Set the selector switch to
(DHW and CH).
2. The burner will light at the ignition rate and will increase to the factory preset maximum output after 1 minute.
3. Turn off the boiler. Disconnect the pressure gauge and tighten the test point screws.
Test for gas soundness using suitable leak detection fluid.
Note: Refer to Technical Data, Section 2.1 for the required differential burner pressures.
Alpha CD50 - Commissioning
Fig. 26
Fig. 25
Differential
Burner
pressure
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