6 720 680 174 (2014/05)
Therm 8000S
34 | Installation instructions
Before adjusting the fan speed it is necessary to verify the
admission / exhaustion system, calculating the total length of
the exhaust pipes and quantity of elbows.
Pressure drop equivalence of the conducts and exhaustion
accessories
8.6.1 Total equivalent vent length calculation Ø80 mm
How to calculate the total length of the exhaust conduct:
▶ Determine the total length of all straight sections of vent
pipe and enter in Table 17 , line 1.
▶ Count the number of 90° elbows used, multiply by 1m, and
enter that value in Table 17 , line 2. (Do not count non-
concentric terminals and first elbow used on intake and
exhaust ).
▶ Count the number of 45° elbows used, multiply by 0.5m,
and enter that value in Table 17 , line 3.
▶ Count the number of 30° elbows used, multiply by 0.4m,
and enter that value in Table 17 , line 4.
▶ Repeat the previous procedure to calculate the total length
of the admission of air conduct. Insert values in Table 18 .
▶ Sum the total of the Table 17 with the total of the Table 18
and to put the result in the line 6 of the Table 18 .
This is the total equivalent vent length.
Example
Exhaust:
• 5 units of 1m straight sections
• 1 unit of 1m straight sections
– Total length = 6 meters
• 2 - 90° elbows
Intake:
• 4 units of 1m straight sections
– Total length = 5 meters
• 2 - 90° elbows
Example table:
Equivalence in meters
Description
Ø80/80mm
Ø80/125mm
30° elbow
0.4m
0.7m
45° elbow
0.5m
1.5m
90° elbow
1m
2m
exhaust pipe per meter
1m
1m
Horizontal vent kit
-
1.5m
Table 16
Do not count non-concentric terminals and
first elbow used on intake and exhaust.
Exhaust
1
Straight section length ___ x 1 =
________
2
90° elbows (qty)
___x 1 =
________
3
45° elbows (qty)
___x 0.5 =
________
4
30° elbows (qty)
___x 0.4 =
________
5
Sub-total:
________
Table 17
Intake
1
Straight section length
___ x 1 =
________
2
90° elbows (qty)
___x 1 =
________
3
45° elbows (qty)
___x 0.5 =
________
4
30° elbows (qty)
___x 0.4 =
________
5
Sub-total:
________
6
Total equivalent vent length=
________
Table 18
Exhaust
1
Straight section length
6 x 1 =
6
2
90° elbows (qty)
_1_ x 1 =
1
3
45° elbows (qty)
_0_ x 0.5 =
0
4
30° elbows (qty)
_0_ x 0.4 =
0
5
Sub-total:
7
Table 19
