Alpha Pro Tec 115, Инструкции по установке и обслуживанию, Страница: 14 / 48

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3.8 CENTRAL HEATING SYSTEM - Fig. 3.3
The boiler is designed for use in a sealed central heating system in accordance with the requirements of BS 5449 and BS 6798.
The system should be designed to operate with flow temperatures of up to 85°C. When designing the system, the pump head,
expansion vessel size, mean radiator temperature, etc. must all be taken into account. Refer to the pump performance graph
Section 2.5 for guidelines.
However, if the boiler is to be used with an open central heating system refer to Fig. 3.3 and use a barrier heat exchanger (i.e.
separates the boiler primary circuit from the open heating circuit). This will also ensure the boiler heat exchanger is protected
from an old/dirty system.
Sealed system volume - An expansion vessel is not incorporated into the boiler. An expansion vessel must be fitted in the
position shown in Fig. 3.3. To check correct operation of the expansion vessel the system pressure should not be more than
3.5 bar when the system is at maximum operating temperature (for further guidance refer to BS 7074:1), For example an 8
litre expansion vessel is suitable for a sealed system of 80 litres.
Expansion vessels should be set to 1 bar before the system is filled.
The boiler is supplied with the following components built in:-
Pressure relief valve - complying with BS 6759 and set to operate at 4 bar. The discharge pipe must be routed clear of the
boiler and terminated in such a manner that it can be seen, but cannot cause injury to persons or property.
Pressure gauge - To indicate the system pressure to be maintained.
By-pass - The boiler has no built-in by-pass, therefore a by-pass is required for the system.
Installation on a low temperature heating system.
The boiler can directly feed a low temperature system, varying the maximum delivery temperature of the boiler and setting
a value of between 20 and 85°C. To vary the boiler maximum delivery temperature, modify the boiler maximum delivery
temperature of parameter No. 02 as described in Section 9.
In this mode it is advisable to include a safety limit thermostat set at 55°C in series with the boiler controls. The thermostat
Fig. 3.3
Alpha Pro Tec - General Boiler Information
must be positioned in the system flow pipe at more than 2 metres from the boiler.
3.9 FILLING THE SEALED CENTRAL HEATING SYSTEM - Figs. 3.4, 3.6
The system design pressure (cold) should be set to 1.0 bar. This pressure is equivalent to a static head (see Fig. 3.3) of 10.2
metres of water.
Provision should be made to replace water lost from the system. This can be by manual or automatic means, as shown in
Figs. 3.4 and 3.5. The position for connecting an automatic make-up vessel is indicated in Fig. 3.3. A double check valve
assembly must be used, as shown in Fig. 3.5.
Make up vessel
(sealed system only)
Automatic
air vent
Expansion vessel
(sealed system only)
Expansion
vessel
(sealed system
only)
Double check valve assy.
(sealed system only)
Filling point
(sealed system only)
Static head of system
Heating return
System
drain tap
Heating flow
Note: A drain tap should be installed at the lowest
point of the heating circuit and beneath the appliance.
Boiler
Heating return
Fit pump if Barrier
heat exchanger used
Heating flow
Barrier heat exchanger used
on open or old/dirty systems
Return
Flow
Flow
Return
Drain
tap