Stationary heater (STH) diagnosis, function check

AD83.70-P-3003GH

Stationary heater (STH) diagnosis, function check

11.5.01

Danger!

Risk of explosion from fuel vapors, risk of poisoning from inhaling combustion gases and risk of injury from burns during and after operation of heater unit.

Do not operate stationary heater, auxiliary heater or engine with heater booster in closed areas or when refueling. Allow heater unit to cool down after operation and wear protective gloves.

AS83.70-Z-0002-01A

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Stationary heater (STH) diagnosis previous knowledge

AD83.70-P-2001GH

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Wiring diagram

AN83.70-P-0001-04GH

Air inlet of heating and fresh air system must not be blocked, remove any foreign bodies such as leaves, if necessary

Vehicle heater must be set to "max" position

All the lines conveying fuel must be connected without leaks, and must not have any damage.

Inspect coolant circuit. The circuit must be adequately filled and carefully bled. Coolant lines must not be bent or squashed.

Coolant temperature  20 °C

Battery voltage 10.5 - 15 V

Operational check

Test scope

Operation/requirement

Specification

Remedy

1

Switch on stationary heater

Stationary heater:

Press instant heat button  on timer or by pressing "ON" button at Telestart transmitter

The flame symbol appears in the display panel of the timer , circulation pump and combustion air blower start; running noises are audible and air flow can be felt at the exhaust outlet

Coolant temperature  59 °C:

Heating circuit thermostat shuts off the inlet to the cooling and heating circuit of the vehicle and, at first, to rapidly increase the temperature at the heater unit, allows only a restricted circulation of the coolant which flows from the heater unit through the thermostat and the circulation pump.

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2

After about 30 s fuel delivery begins and the combustion air blower is switched off for 3 s

Fuel metering pump cycles audibly

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3

Combustion air blower is switched on again and at the same time the clock frequency of the fuel metering pump is reduced

Running noises of combustion air blower and slower clocking noise of fuel metering pump are audible

AD83.70-P-4002GH

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4

Gasoline engines:

Combustion air blower increases its speed in 2 stages within about 60 s, combustion commences and fuel delivery is increased

Diesel engines:

Combustion air blower increases its speed in 2 stages within about 60 s. After a stabilization phase of 15 s the combustion air blower is increased to full output by rising in a time slope of 50 s. Combustion commences and fuel delivery is increased

Audible increase in combustion air blower speed and cycling noise of fuel metering pump and exhaust gas flow heats up detectably at the same time

AD83.70-P-4002GH

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5

Combustion commences and stabilizes

Combustion air blower and fuel metering pump audibly pump at maximum speed and capacity in full load operation, the coolant temperature rises.

Coolant temperature in cooling and heating circuit > 30 °C:

Blower of vehicle heater starts; running noises audible and warm air flow can be felt in interior

Coolant temperature exceeds 59 °C:

Heating circuit thermostat opens the passage to the cooling and heating circuit of the vehicle for the coolant, the heat exchange in the heating system heat exchanger commences for warming up the interior

AD83.70-P-4002GH

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6

Switch off stationary heater

Stationary heater

Press instant heat button  on timer or by operating the "ON" button at the Telestart transmitter

The flame symbol in the display panel of the timer goes out, the blower of the vehicle heating system and the fuel metering pump are switched off immediately. The air flow in the interior can no longer be felt and the clocking noise of the fuel metering pump is no longer audible

AD83.70-P-4002GH

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7

Heater unit delayed off commences

Gasoline

from part load operation  delayed off approx. 160 s

from full load operation  delayed off approx. 170 s

Diesel

from part load operation  delayed off approx. 110 s

from full load operation  delayed off approx. 175 s

Circulation pump and combustion air blower continue running; running noises audible and slowly cooling air flow can be felt at exhaust outlet

AD83.70-P-4002GH

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8

Delayed off phase ends

Running noise of circulation pump and of combustion air blower no longer audible and no air flow felt at exhaust outlet

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