wallas Nautic 40D, Operator'S Manual With Installation Manual

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WALLAS 40D
Operator’s Manual and Installation Guide
8
Inlet air ductlng
Inlet air for the Nautic 40D furnace is taken through two 3 inch (75mm) air ducts. This allows the
furnace to be installed in the engine compartment or other spaces where the air may be foul.
One of the 2 x 3 inch (75mm) suction connections of the furnace is installed to extract fresh air
from the outside, and the other to extract air from inside the boat. Protective grilles without
throttle valves are attached to the ends of the suction pipes, and the opening for outdoor air also
needs to be protected appropriately against the weather.
For safety reasons the furnace must not be installed In a place where gasoline fumes
might be present.
The suction air is taken in via two branches of ducting. One inlet duct should take in some fresh
air and the other inlet duct should take in return air from inside the boat. (See Figures 12, 14,
15)
The longest permissible length of one branch of the suction air duct is 8 ft, based on a minimum
diameter of the inlet air ducts being 3" to prevent excessive pressure drop.
Protective grilles should be connected to the ends of the inlet ducts. These grilles are available
from Scan Marine.
Protect the opening of the fresh air inlet ducts with some form of weather/vermin shield.
Protective shields for this purpose are available at most marine supply stores.
All inlet duct connections should be secured with hose clamps.