7
Alpha CD90S/115S - General Boiler Information
3.1
GAS SUPPLY
Natural Gas:
The Alpha CD90S boiler requires a gas rate of 8.9 m³/h (297 ft³/h).
The Alpha CD115S boiler requires a gas rate of 10.6 m³/h (355 ft³/h).
Propane Gas (LPG):
The Alpha CD90S boiler requires a gas rate of 7.17 kg/h or 14 litres/h of liquid gas.
The Alpha CD115S boiler requires a gas rate of 8.76 kg/h or 17.2 litres/h of liquid gas.
The local Propane Gas supplier should be consulted, at the installation planning stage, in order to establish the
availability of an adequate supply of gas.
The meter and supply pipes must be capable of delivering this quantity of gas in addition to the demand from any other
appliances. The boiler requires at least a 35 mm gas supply pipe and ensure the inlet supply pressure is at least 20 mbar
for Natural Gas or 37 mbar for Propane Gas (LPG).
The complete installation, including the meter, must be tested for gas tightness and purged as described in BS 6891.
3.2
ELECTRICAL SUPPLY
The boiler requires a 230/240 V ~ 50 Hz mains supply, fused at 3 A
Note: The boiler must be earthed.
There must only be one common isolator, providing complete electrical isolation, for the boiler and any external controls.
This boiler has been fitted with a supply cable, however, if it is necessary to fit a cable use PVC insulated cable not less
than 0.75 mm² (24 x 0.2 mm) to BS 6500 Table 16. The boiler should be connected to a fused three pin plug and
unswitched shuttered socket outlet (both complying with BS 1363), or a fused double pole switch with a contact
separation of at least 3 mm in both poles.
Wiring external to the boiler must be in accordance with the current IEE Wiring Regulations (BS 7671).
3.3
AIR SUPPLY
Open flued (Type B23 flue)
Alpha CD90S and CD115S boilers leave the factory with 'B23' type configuration (open chamber and forced draught -
single flue pipe) and receive the air for combustion from openings in the rear of the boiler, therefore air supply for
combustion and ventilation must be provided in accordance with BS6644.
Note:
Where a boiler installation is to operate in summer months (e.g. DHW) additional ventilation requirements are
required if operating more than 50% of the time (refer to BS 6644).
Room sealed (Type C flue)
If the boilers are converted to a 'C' type configuration (sealed chamber and forced draught - concentric flue pipe) as
described in Section 3.4 only air for ventilation is required.
A minimum of 2 cm² free area per kW of net heat input at both high and low level is required for boiler rooms. For
enclosures refer to BS 6644.
The minimum clearances for servicing must always be maintained.
3
GENERAL BOILER INFORMATION
