Technical data

18
5.6 FINAL COMMISSIONING
1. Allow the heating system to heat up, then balance the system to achieve the necessary temperature difference across the
heating flow and return pipes at the boiler and check the system volume and pressure. (Refer to Technical Data, sections
2.8 and 2.10).
2. Turn off the boiler.
3. Thoroughly flush out the water pipework and clean the filters in the heating return and mains water inlet isolating valves.
4. Re-pressurise the system as described in section 5.1.
5.7 FINAL ASSEMBLY
1. Raise the control panel and secure in position with the screws previously removed.
Alpha 240XP only - Ensure the gas control locates correctly over the black cap on the gas valve knob.
2. Place the front casing in position over the boiler ensuring the bottom is located behind the control panel and secure in
position at the top using the screws previously removed.
3. If the boiler is to be left in service with the User, set the controls, clock (if fitted, see User's Operating manual) and room
thermostat (if fitted) to the User's requirements.
4. If the boiler is not to be handed over immediately, close the boiler gas service cock and switch off the electrical supply.
5. If there is any possibility of the boiler being left during frost conditions, then the boiler and system should be drained.
(Refer to Component Replacement, section 8.2).
It is recommended that a label is attached to the boiler drawing attention to the fact that the system has been drained.
6. Complete the details of the installation on the back page of this manual.
5.8 USER INFORMATION
The User must be advised (and demonstrated if necessary) of the following important points:-
1. How to light and turn off the boiler and how to operate the system controls.
2. The importance of annual servicing of the boiler to ensure safe and efficient operation.
3. That any servicing or replacement of parts must only be carried out by CORGI registered personnel.
4. Ensure that the boiler controls and room thermostat (if fitted) are set to the User's requirements.
5. Tell the User about the sealed system pressure.
6. Tell the User that if the electrical supply is on and the boiler has not operated for 24 hours for heating or hot water, the
pump will automatically operate for 5 minutes.
7. Explain to the User that an internal frost thermostat is fitted in the boiler, and that elecrical supply to the boiler must be left
on, and for the Alpha 240XP boiler, the pilot is alight, for the thermostat to operate.
8. Show the User the position of the pressure relief valve discharge pipe.
9. Hand the User's instructions to the User.
10. Leave these Installation and Servicing instructions with the User for use on future calls.
Alpha 240XP and 240XE - Commissioning/Boiler Operation
6 BOILER OPERATION
The boiler operating mode is controlled by the selector switch on the facia panel. When set to , the boiler will only operate in
the Domestic Hot Water mode. When set to , it will operate in the Domestic Hot Water and Central Heating mode.
Note: The clock (if fitted) only controls the operating times of the central heating, not domestic hot water - DHW is available continuously.
Domestic hot water supply always takes priority over central heating. If a demand for hot water is required during a central
heating period, the boiler will automatically switch to the hot water mode until the demand is satisfied. This interruption in the
central heating is only when the demand for hot water is present and should not be noticed by the User.
6.1 CENTRAL HEATING MODE
If there is a call for heat, the pump will start to circulate the central heating water, operating the flow switch. The fan will run at
full speed; once the air pressure switch is proved the burner will light. The burner output then automatically adjusts to suit the
system demand; as the temperature of the water in the boiler approaches that set by the adjustable temperature selector, the
burner output is reduced. When the set temperature is reached, the burner is turned off and the fan stops (the fan drops to low
speed on the Alpha 240XP). The pump continues to run for five minutes to remove residual heat build up in the boiler. The
burner will not relight for 3 minutes. If the CH sensor has not registered the pre-set temperature but the room thermostat is
satisfied the burner is turned off, the fan stops (the fan drops to low speed on the Alpha 240XP) and the pump continues to run
for five minutes. In this instance there is no 3 minute delay before the burner will relight.
If there is a demand for DHW during the 3 minute burner delay, the boiler will operate to provide DHW until the tap is closed;
the boiler will then immediately revert to provide CH if there is a demand.