INSTALLATION
Webasto BlueCool Classic Series
18
4.3
Air Ducting - Ventilation
1) Minimum Air Grill Sections:
In order to obtain an acceptable noise level at max. blower speed
certain requirements regarding grill and duct sections should be observed. Also, the size of the
transition box behind the supply air grill is important. See Table 2 to select correct grill sections
according to BTU rating.
2) Duct Type:
To avoid accidental crushing, flexible air-ducts should be of high quality with sufficiently
strong steel spiral reinforcement. Spiral type ducts should be extended to their maximum possible
length to obtain max. interior smoothness. For very long duct sections preference should be given to
rigid ducts (in PVC for example) which offer a far greater smoothness than flexible spiral type ducting
and therefore will greatly reduce internal friction. For very short lengths non-insulated ducts may be
used. Over greater lengths it is advisable to use insulted type ducts to avoid condensation on the
outside of the air-ducts.
Table 2
Air Duct Requirements
BLUECOOL
CLASSIC
MODEL
SUPPLY AIR GRILL
MODEL/SECTION
RETURN AIR GRILL
MODEL/SECTION
DUCT DIAM.
<1.8 m (6 ft.)
DUCT Length
DUCT DIAM.
>1.8 m (6 ft.)
DUCT Length
5,000
BTU
1 x 8x4”
150 cm²
1 x 12x5”
325 cm²
80 mm (3”)
100 mm (4”)
7,000
BTU
1 x 10x4” 190 cm²
1 x 11x8”
490 cm²
100 mm (4”)
125 mm (5”)
9,000
BTU
1 x 12x4” 235 cm²
1 x 11x8”
490 cm²
100 mm (4”)
125 mm 5”)
12,000 BTU
1 x 10x5” 250 cm²
1 x 14x7”
550 cm²
125 mm (5”)
150 mm (6”)
16,000 BTU
1 x 12x6” 390 cm²
or
2 x 10x4” 380 cm²
1 x 14x10” 800 cm²
125 mm (5”)
150 mm (6”)
24,000 BTU
2 x 10x5” 500 cm²
1 x 14x12” 1,000 cm² 2 x 125 mm (5”)
2 x 150 mm (6”)
30,000 BTU
2 x 12x5” 650 cm²
2 x 14x10” 1,600 cm² 2 x 125 mm (5”)
2 x 150 mm (6”)
NOTE: For duct lengths over 1.80 m, it may be possible to use the nominal duct diameter (for example
100 mm - 5,000 BTU model), if instead of spiral type flexible ducts, rigid perfectly smooth interior ducts
are used.
