Benchmark Alpha CD18S Installation And Servicing Instructions page 5

2.5 INSTALLATION
Min. Clearances for Servicing
(from casing)
Flue Terminal Size
Flue Terminal Protruding
Hole Size Required For Flue Assy.
Lift Weight
2.7 FLUE LENGTHS
CD Easy-Flue 500 mm with terminal and 90° bend. A CD Easy-Flue 1000 mm with terminal and 90° bend is also available.
CD 750 mm and CD 1000 mm flue extensions are available.
Length of Flue Required:-
Rear Flue = wall thickness + 170 mm (includes terminal)
Side Flue = wall thickness + distance between wall and side of boiler + 230 mm (includes terminal)
Vertical Flue = distance from top of boiler side panel to required roof position minus 1 m for vertical terminal assembly
Maximum horizontal flue length = 12 m.
Maximum vertical flue length including terminal is 15 m.
Each additional CD 90° Bend is equivalent to 1.3 m of flue length.
Each CD 45° Bend is equivalent to 0.9 m of flue length.
The CD Vertical Flue terminal assembly is equivalent to 1 m of flue length.
2.8 AVAILABLE PUMP HEAD FOR CENTRAL HEATING
Output (50/30°C) Available pump head
kW Btu/h
metres
2.3
25.40 86 700
3.5
18.70 64 000
3.8
15.60 53 000
4.0
12.35 42 200
4.6
5.30 18 100
This information is based on 20°C system design temperature difference. Note: For outputs upto 30 kW refer to Section 3.7.
2.9 ELECTRICAL CONNECTIONS
Note: This Appliance Must Be Earthed
An optional integral two channel Clock kit (Part No. 6.1000220) is available if required.
Note: Only use the Alpha two channel clock. Do not fit any single channel clocks.
White Grey Black
wire
wire wire
5 4 3
Internal 2 Channel Clock Terminals
WARNING
1. Ensure wires are connected
correctly
2. Only fit the Alpha recommended
2 channel clock. Other clocks
could cause damage.
Clock connections
4 Alpha CD18S/24S/30S - Technical Data
Top 220 mm
Bottom 250 mm
Sides 5 mm
Front 450 mm
100 mm Dia.
100 mm
110 mm Dia.
CD18/24 46 kg
CD30 48 kg
20°C
feet litre/min
7.6
16.6
11.6 12.6
12.6 10.5
13.2 8.3
15.2 3.2
Blue Brown
wire wire
2 1
2.6 GENERAL
Case Dimensions
Gas Connection
Primary Water Content
Air Duct Diameter
Flue Duct Diameter
Flow rate
20°C
gal/min
3.7
2.8
2.3
1.8
0.7
Fuse - Always fit fast blow 2 A
Live (Brown wire)
Neutral (Blue wire)
Earth (Green/Yellow wire)
Switched Live
230/240 V (Ch1 ON)
Use only when internal
Ch1 OFF
two channel clock is
Ch2 ON
fitted
Boiler terminal block
Fig. 1
Height
Width
Depth CD18/24
Depth CD30
CD18
CD24/30
CD18/24
CD30
230/240 V ~ 50 Hz
Fuse supply 3 A
Note: To connect external
control, remove link from
terminals 1 and 2 and
connect a 230/240 V
switched live to terminal 1
850 mm
450 mm
345 mm
380 mm
15 mm
22 mm
2.5 L
3.0 L
100 mm
60 mm