Supplied By www.heating spares.co Tel. 0161 620 6677
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Alpha CB24/28
The operating sequence of the boiler is controlled by the selector switch on the control panel. With the switch set to
(hot water
only) the boiler will only operate to provide domestic hot water, ideal for Summer use when central heating is not required.
Setting the selector switch to
(central heating and hot water) the boiler will operate to provide both central heating and
hot water.
If the boiler is operating to provide central heating and a hot water tap is opened, the boiler will automatically switch over to provide
hot water. Such an interruption in the central heating should not generally be noticed by any reduction in room temperature.
Note: If a clock is fitted to the boiler, it will only control the operating times of the central heating. Hot water will always be
available when a tap is opened.
When the selector is set to central heating and hot water, it will respond to a demand for heat in the following sequence:-
a. The pump will start, the fan will operate at full speed and the main burner will light.
b. The output of the burner is automatically controlled to suit the system demand.
c. When the temperature of the system water in the boiler reaches that set by the thermostat or the room thermostat is
satisfied, the main burner is turned off and the fan stops after 20 seconds. The pump will continue to run to remove any
residual heat from the boiler.
d. When a hot tap is opened, the boiler automatically senses a flow of water. The pump will start, the fan will operate at full
speed and the main burner will light.
e. The boiler will continue to supply hot water at the temperature set by the thermostat until the tap is closed.
The supply of hot water is almost instantaneous at the boiler, but the time taken to reach a tap and the temperature at which it leaves
the tap will depend on the rate at which the water is drawn off and the length of the pipe between the tap and the boiler.
Fully opening a hot tap may not always provide the maximum temperature as the flow rate may be too high, try closing it slightly
until the maximum temperature is achieved.
The CB24 and 28 boilers are fitted with a seasonality valve which will automatically adjust the flow rate for both summer and
winter conditions.
Depending on your mains water pressure, it may not be possible to operate several hot taps at the same time.
Thermostatic or pressure equalising type - When using these types of shower set the boiler domestic hot water thermostat
to maximum. The shower should then maintain a relatively constant temperature.
Manual bath mixer type shower - When using this type of shower set the boiler domestic hot water thermostat to setting 7,
This should avoid excessive temperatures at the shower.
Note: If you get unacceptable temperature variations with this type of shower, then a thermostatic or pressure equalising type
should be used.
1. BOILER LOCATION
Always ensure the following clearances are available around the casing of the boiler (not including the bottom tray):-
Top: 220 mm, Bottom: 250 mm, Each side: 5 mm, Front: 450 mm
Do not store any other articles in the cupboard containing the boiler and never place any clothing or combustible material on or near
the boiler or flue pipe.
2. FLUE TERMINAL
The terminal on the outside wall must not be allowed to be obstructed. If it is damaged, in any way, turn the boiler off and
contact your Service Engineer. In cold weather, vapour may be emitted from the terminal. This is quite normal.
3. MAINS FAILURE
In the event of an electrical supply failure the boiler will not operate. When the supply is restored, the boiler will return to normal
operation. Remember to reset the clock when the supply is restored.
If the mains water supply fails, there will be no hot water from the taps. The boiler will continue to provide central heating.
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BOILER OPERATION
6
HOT WATER USE
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USING A SHOWER
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IMPORTANT NOTES
