NGW 300 / LGW 300 / GBW 300
2 General description
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2
General description
The NGW 300, LGW 300 and GBW 300 water heaters
operate in conjunction with the on-board heating system
–
to heat the passenger compartment
–
to defrost the window panels and
–
to heat the water-cooled engines
in busses.
Water heaters operate independently of the vehicle’s en-
gine and are connected to the cooling system, the gas sy-
stem and the electrical system of the vehicle.
Heater type:
NGW 300
for the CNG type of gas (natural gas)
LGW 300
for the LPG type of gas (propane)
GBW 300
NGW 300 version for the CNG type of gas (natural gas)
LGW 300 version for the LPG type of gas (propane)
The heater which is designed to work in accordance with
the heat exchange principle is controlled by the
regulating thermostat in intermittent operation
The heater basically consists of
–
the burner head
–
the heat exchanger and
–
the combustion chamber zusammen
The following components are located in the heater:
–
a control unit
–
a flame monitor electrode
–
an ignition spark generator with ignition electrodes
–
a regulating thermostat
–
a temperature limiter and
–
a vacuum switch
imfor control and monitoring.
In addition, a circulating pump and a gas pressure regula-
tor for the gas are installed in the vehicle to supply the hea-
ting system as well as a thermostat valve for heating the
gas pressure regulator. The NGW 300 also has a time-
delayed solenoid installed in the heater’s gas suction hose.
Fig. 201 NGW 300 water heater
1 Burner head
2 Coolant inlet
3 Temperature limiter
4 Regulating thermostat
5 Coolant outlet
6 Heat exchanger
7 Exhaust fume outlet
8 Gas inlet
9 Differential pressure connection
10 Combustion air intake
11 Ignition spark generator
12 Control unit
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