Desa BNG150T - Manual (Page 4)

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NATURAL GAS CONSTRUCTION HEATER
150,000 BTU/HR
Air For Combustion
And Heating Fuel
Combustion
Chamber
DSI
Ignitor
Figure 2 - Cross Section Operational View
Clean
Heated
Air Out
(Front)
Cool Air
In (Back)
THEORY OF
OPERATION
The Fuel System: The gas supply at-
taches to the heater by a minimum 3/4 inch
i.d. hose or flexible connector. User must
supply hose or flexible connector. The length
should be no more than 10 feet long. The
natural gas moves through the solenoid valve
and the internal regulator and out the nozzle.
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.
Fan
Motor
Power
Cord
On/Off Switch
Solenoid
Valve
Nozzle
NATURAL GAS
SUPPLY
The user must furnish the natural gas sup-
ply and the connections to the heater.
Regulate the natural gas supply down from
a minimum 5 inches water column to a
maximum of 1/2 psi. The natural gas supply
capacity should be able to supply a mini-
mum of 150 cubic feet of gas at pressure for
each heater connected to the system.
Consult your natural gas supplier for proper
sizing of the natural gas supply lines.
Follow all local ordinances and codes. In
the absence of local ordinances and codes,
refer to the National Fuel Gas Code Hand-
book, NFPA54/ANSI Z223.1 and the Natu-
ral gas Installation Code, CAN/CGA
B149.1.
Internal
Regulator
The Ignition System: The direct spark
ignitor (DSI) sends voltage to the ignitor.
The ignitor ignites the fuel and air mixture.
The Safety Control System: This sys-
tem causes the heater to shut down if the
flame goes out.
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.
VENTILATION
Provide a fresh air opening of at least three
square feet for each 100,000 Btu/Hr rating.
Provide extra fresh air if more heaters are
being used.