Theory Of Operation - Desa B350D Owner's Manual

HIGH PRESSURE PORTABLE FORCED AIR
HEATER 350,000 AND 600,000 BTU/HR
THEORY OF
OPERATION
The Fuel System: The motor turns the
fuel pump. The fuel pump pulls fuel from
the fuel tank. The fuel pump pushes fuel
through a filter and a solenoid valve and out
the burner head nozzle. A fine mist of fuel is
sprayed into the combustion chamber.
The Air System: The motor turns the fan.
The fan pushes air into and around the
combustion chamber. This air is heated and
provides a stream of clean, hot air.
The Ignition System: The electronic ig-
nitor sends voltage to the spark plug. The
spark plug ignites the fuel and air mixture.
The Flame-Out Control System: This
system causes the heater to shut down if the
flame goes out. It also allows the fan to
continue running after normal shutdown of
heater. This cools the combustion chamber.
Combustion
Chamber
Clean
Heated
Air Out
Fuel Tank
Nozzle
Figure 3 - Cross Section Operational View
FUELS
WARNING: Use only kerosene
or No. 1 fuel oil to avoid risk of fire
or explosion. Never use gaso-
line, naphtha, paint thinners, al-
cohol, or other highly flammable
fuels.
Do not use heavy fuels such as No. 2 fuel oil
or No. 2 diesel. Using heavy fuels will result
in:
• clogged fuel filter and nozzle
• carbon build-up on spark plug
• the need of non-toxic anti-icer in fuel
during very cold weather
IMPORTANT: Use a KEROSENE ONLY
storage container. Be sure storage container
is clean. Foreign matter such as rust, dirt, or
water will cause flame-out control to shut
down heater. Foreign matter may also re-
quire you to clean fuel system often.
Solenoid
Valve
Burner
Spark
Head
Plug
Fuel Line To
Electronic Ignitor
Solenoid Valve
Air for Combustion
and Heating
Fuel Pump/
Fuel Filter
Motor
Fan
Cool
Air In
Fuel
Pickup
Line
Fuel
Filter
Fuel
4
VENTILATION
WARNING: Follow the mini-
mum fresh, outside air ventila-
tion requirements. If proper fresh,
outside air ventilation is not pro-
vided, carbon monoxide poison-
ing can occur. Provide proper
fresh, outside air ventilation be-
fore running heater.
Fresh Air Opening
Requirements
Square Feet
Heater Size Opening
350,000 Btu/Hr
600,000 Btu/Hr
Note: If you use more than one heater,
provide extra fresh air. Provide a fresh air
opening of at least three square feet for each
100,000 Btu/Hr rating.
10.5
18.0
099507