Bosch 12/18 User Manual

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BALANCED EXTERNAL OILFIT
FLUE OPTIONS
INSTALLATION & SERVICING INSTRUCTIONS FOR WORCESTER GREENSTAR HEATSLAVE EXTERNAL 12/18-18/25-25/32
8 716 113 389b (09/07) 
16
P
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IN
ST
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LA
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IMPORTANT: The weather seal (supplied) 
must be fitted to every flue joint to give 
the required level of weather protection.
The diagrams (opposite) show the components
used and the maximum flue length (L) for
each flue configuration.
In all cases L is measured from the outside of
the boiler casing.
• To achieve the maximum flue length (L), a flue
section will have to be reduced in length.
• Only the straight flue extensions can be
reduced in length by cutting.
IMPORTANT: All horizontal sections must 
rise away from the boiler by 52mm per 
metre (3°) to allow the condensate to 
drain back to the boiler.
A - Horizontal terminal
B - Straight flue extension
C - Flue bend 90°
D - Flue bend 45°
E - Vertical Terminal Kit (incl. 90° elbow)
F - Horizontal terminal kit (incl. 90° elbow)
Calculating the flue length:
Measure the total flue length required, noting
that the maximum straight flue length including
the terminal is:
Horizontal 80/125mmØ: 4000mm. 
Vertical 80/125mmØ / 100/150mmØ (25/32
only): 7000mm.
Then reduce the total straight flue length for
each extra flue bend (excluding the vertical flue
kit 90° elbow) by:
1000mm for 90°
500mm for 45°
Flue Extension lengths:
Horizontal & Vertical: 1000mm overall length.
Effective length when engaged into sockets
within the flue run is 950mm.
Flue Terminal lengths:
Horizontal 80/125mmØ: 720mm
Vertical 80/125mmØ: 1080mm + cage
*   Rear exit only.
** Horizontal flue runs should be kept as 
short as possible.
L = 6000mm
125mmØ x4
 L 
L = 2000mm
125mmØ x2
B
D
D
B
E
E
B
C
D
A
 L 
F
F
L = 7000mm
125mmØ x5
 L 
E
B
L = 6000mm
125mmØ x4
B
E
 L 
C
BALANCED EXTERNAL OILFIT
FLUE OPTIONS
High level horizontal terminal (rear outlet) 
*
**
Vertical terminal (rear outlet)  
Vertical terminal (rear outlet) 
Vertical terminal (side outlet) 
**
**
**