wallas 22 Dt Mode D'emploi page 58

Heater's operation principles
D80031
22 Dt / 30 Dt / 40 Dt
Technical information
Operation description
The 22 Dt, 30 Dt and 40 Dt heaters are forced air diesel heaters without an ex-
posed flame.
The 22 Dt and 30 Dt models take combustion air from outside the boat through the
outer coaxial exhaust gas pipe and blow their exhaust out through the inner coaxial
pipe. The coaxial pipe connects to a common through hull fitting that allows both
inlet air and exhaust to pass separately. This process improves efficiency, wind
resistance and lowers the minimum power level. The model 40 Dt takes combus-
tion air from its place of installation and blows the exhaust gas out through a single
pipe.
For all these models, fresh makeup air is taken from desired areas with air intake
ducting, e.g. from outside of the boat or inside the cabin. This enables good air
circulation and cabin air replacement. Diesel engine compartment installations are
supported by the separate makeup air intake ducts, quarantining the makeup air
away from any smells or noxious engine fumes.
The heat generated by forced air fuel combustion, is transferred to the circulation
air by a heat exchanger. The heating power can be adjusted freely between high
and low output settings by manual rheostat control or by thermostat. The heated
air is circulated through the cabin through the warm air ducting.
In hot and/or humid conditions, these heating units can be used for simple fresh air
ventilation and circulation.
When starting the device, the glow plug ignites the pumped fuel in the burner bowl.
The glow/start and shut down sequences are factory programmed, so - starts and
stops are automatically controlled.
The fuel pump inside the heater case regulates the fuel feed and the system
electronics control both the fuel and air mixture to maintain the ideal clean burning
process. The temperature sensor inside the burner feels the ignition and lights up
the red signal light (1) to indicate a successful start. When stopping the device, an
automatic after cooling process takes place. This process cleans the burner, purg-
ing any unburned fuel.
The heaters are completely made out of corrosion resistant materials.
- 58 -
en
K00120
490526C