Alpha CD12S, Installation And Servicing Instructions

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22 Alpha CD12S/20S/28S - Commissioning
5 COMMISSIONING
Fig. 26
0
1
2
3
1
2
3
4
5
6
7
8
9
bar
0 4
3
2
1
RESET
FROST
A
D
B
C
SELECTOR THERMOSTAT
OFF
ON
Clock (if fitted)
Indicator
Neons
Selector Switch
Central
Heating Thermostat
System
Pressure Gauge
When commissioning the boiler, ensure the Benchmark Checklist is completed.
5.1 FILL THE SYSTEM
1. The boiler is fitted with an automatic air vent positioned on the pump (see Fig. 2), ensure that the vent is always open.
2. Open the central heating flow and return valves (vertical slot in-line with valve) (see Fig. 14).
3. Open the fill point valve on the filling loop until water is heard to flow. To aid venting, the boiler drain point (see Fig. 14)
may be opened until water flows out. Close the drain point as soon as water appears.
4. To remove the air - Vent each radiator in turn, starting with the lowest in the system.
5. It is important that the pump is properly vented to avoid it running dry and damaging its bearings. Unscrew and remove the
cap from the centre of the pump. Using a suitable screwdriver rotate the exposed spindle about half a turn, then replace
the cap.
6. Check the operation of the pressure relief valve (see Fig. 2) by turning the head anti-clockwise until it clicks. The click is
the valve lifting off its seat allowing water to escape from the system - check that this is actually happening.
7. Continue to fill the system until the pressure gauge indicates 1.0 bar. Close the fill point valve and check the system for
water soundness, rectifying where necessary. Disconnect the filling loop from the mains supply.
Water may be released from the system by manually operating the drain point (see Fig. 2) until the system design
pressure is obtained. The system design pressure (cold) should be between 0.75 and 1.25 bar.
Refer to Sections 3.8 and 3.9. Filling and Flushing the system.
8. Ensure that the condensate trap has been filled with water. Refer to Section 4.5, paragraph 4.
5.2 BOILER CONTROLS - Fig. 26
5.3 TEST FOR GAS TIGHTNESS AND PURGE THE SUPPLY
1. With the boiler gas service cock closed (slot at right angles to valve). Pressure test the gas supply and inlet pipework
connection to the boiler gas service cock for tightness in accordance with BS 6891.
2. Loosen the gas inlet pressure test point screw on the gas valve (see Fig. 23). Ensure the gas supply is on and open the
boiler service cock to purge in accordance with BS 6891.
3. Retighten the test point screw and test for gas tightness. Close the boiler gas service cock.
5.4 INITIAL LIGHTING - Refer to Fig. 22
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 central heating thermostat to maximum.
5. Set the selector switch to
(CH). The boiler will now run in the central heating mode. The pump will start, the fan will
start and the main gas valve solenoid will open allowing the main burner to light.