11
¨
The total length of horizontal air/flue system must not exceed
4 m
. Furthermore, each extra 90
0
concentric elbow or two pieces of 45
0
concentric elbow decreases the maximum length
1m
(fig. 8). The maximum number of 90
0
elbow to be used is 3.
a)
b)
c)
fig. 8
¨
Mounting the restrictor:
The restrictor should be mounted on the fan outlet according to the length of the air/flue connection
to provide efficient combustion and suitable combustion products. (Table 3)
Table 3
Product
Elbow
L (m)
Lmax (m)
restrictor
(mm)
1x90
0
≤
1
∅
43
1x90
0
1<
≤
2
∅
45
1x90
0
2<
≤
3
∅
47
1x90
0
3<
≤
4
4
-
2x90
0
≤
1
∅
45
2x90
0
1<
≤
2
∅
47
2x90
0
2<
≤
3
3
-
3x90
0
≤
1
∅
47
22 HS -11
3x90
0
1<
≤
2
2
-
