ideal commercial EVO S, Product & Flue Manual

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21
For concentric flue systems with elbows fitted, use the table to correct the maximum flue extension capability.
Alternatively use the table to design the flue system, deducting the individual resistance of components from
the maximum pressure drop allowed in the flue for that boiler. The maximum pressure drop allowed in the flue is
given below.
The maximum permissible flue lengths for each model are shown in Table 1 below, these lengths are inclusive of
the terminal resistance. The value shown is the maximum available length for extension. The equivalent length of
elbows is shown in Table 2.
FLUE RESISTANCES
FLUE SYSTEMS
TABLE 1
MAX PERMISSIBLE EQUIVALENT FLUE LENGTH
(INC TERMINAL RESISTANCE) (METRES)
CONCENTRIC
HORIZONTAL
CONCENTRIC
VERTICAL
OPEN FLUE
Flue Size 80/125 100/150 80/125 100/150 80 100
Model
50 12.2 - 11.2 - 20 -
50 LPG 10.2 - 9.2 - 20 -
70 - 12.5 - 11.2 - 83
70 LPG - 12.5 - 11.2 - 83
95 - 12.5 - 11.2 - 50
95 LPG - 12.5 - 11.2 - 50
115 - 10.5 - 9.2 - 24
135 - 8.5 - 7.2 - 40
TABLE 2
EQUIVALENT LENGTH OF ELBOWS
(METRES)
CONCENTRIC OPEN FLUE
Size 80/125 100/150 80 100
45˚ 0.85 1.25 0.45 0.60
90˚ 1.60 1.90 1.00 1.00
EXAMPLES OF FLUE LENGTH CALCULATION
MODEL FLUE TYPE
MAX
PERMISSIBLE
EQUIVALENT
LENGTH
(TABLE 1) (M)
ELBOWS
MAX
PERMISSIBLE
STRAIGHT
LENGTH (M)
TYPE
EQUIVALENT
LENGTH
(TABLE 2)(M)
NO
TOTAL
EQUIVALENT
LENGTH (M)
50 80/125 Concentric Horizontal 12.20 90 1.60 1 1.60 10.60
50 LPG 80/125 Concentric Vertical 9.20 45 0.85 2 1.70 7.50
50 80 Open Flue 20.00 90 1.00 2 2.00 18.00
70 100/150 Concentric Horizontal 12.50 90 1.90 1 1.90 10.60
115 100/150 Concentric Vertical 9.20 45 1.25 2 2.50 6.70
135 100 Open Flue 40.00 90 1.00 2 2.00 38.00
PERMISSIBLE FLUE LENGTH