Combustion System; All Systems Working Together - Desa R35D Service Manual

IV. COMBUSTION SYSTEM
Air being blown by the fan is directed by the air deflectors into
the combustion chamber through the two louvers and center
opening in the rear head which is riveted to the back of the
combustion chamber. The nozzle and nozzle adapter are
mounted in the burner strap which is fastened to the rear
head. As the atomized fuel exits the nozzle and is ignited it
mixes with the air entering through the rear head. The
combustion process is completed inside the combustion
chamber and the hot air exits the outlet end of the chamber.
Air Deflector
For replacement parts contact:
Hot Surface Ignition Models Service Manual
Fan
K
V. ALL SYSTEMS WORKING TOGETHER
There are four basic systems within the heater: the fuel
system, the air system, the electrical system, and the com-
bustion system.
An air pump (A) on one end of the motor shaft forces air
through the air line (G) and out the nozzle (I). The moving air
creates a pressure differential in the nozzle adapter (N)
causing fuel to be drawn from the tank (J). The fuel-air mixture
is sprayed into the combustion chamber (L) in a fine mist.
Additional air is supplied to the combustion chamber by a fan
(O) to enter the combustion chamber where it mixes with the
air and fuel from the nozzle. The remaining air is directed
around and over the combustion chamber. This air mixes with
the heated air from the combustion chamber and is ejected as
a jet of clean, heated air (K).
The ignition system consists of an ignition control assembly
(E) and hot surface ignitor (M). The ignition control assembly
applies 120 volt power to the hot surface ignitor for 10 seconds
which consists of a 5 second preheat period and a 3 to 4
second ignition trial period. The extremely high temperature
of the ignitor element ignites the fuel and air mixture within the
combustion chamber. After the trial period the power is
removed from the ignitor.
In the safety circuit, the photocell monitors the amount of
flame turbulence inside the combustion chamber.
M
L
J
I
Air For Fuel System
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A
O
N
G E
Fuel
Air For Combustion