Stationary heater (STH) diagnosis, fault memory

AD83.70-P-4002A

Stationary heater (STH) diagnosis, fault memory

12.8.97

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Stationary heater (STH) diagnosis, advanced information

AD83.70-P-2001A

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Connection and use of test equipment

AD00.00-P-1000AZ



Connect Hand-Held Tester (HHT) and read out fault memory

AD00.00-P-2000-03A

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Notes on diagnosis with Hand-Held Tester (HHT) on heater booster/stationary heater

AD83.70-P-2001-02A

 If a fault is displayed, check fuses, cables, plugs and connectors in accordance with the relevant electric wiring diagram for open-circuit and correct connection.

Fault memory

Fault code 

Possible cause

Note

Remedy

No fault code

No fault recognized

If there is a complaint nevertheless:

Stationary heater (STH) diagnosis, troubleshooting

AD83.70-P-5001A



Stationary heater/heater booster control module (A6n1) defective

Replace stationary heater/heater booster control module (A6n1)



No flame at the start of heater operation nor after automatic repeat start.

See HHT





Flame goes out during heater operation without a new flame after automatic attempt at starting

Flame goes out more than four times during a heater boost cycle

See HHT

See HHT



Overvoltage



Undervoltage

Operating voltage has exceeded 15.5 V for more than 6 seconds

Operating voltage has been below 10.2 V for more than 20 seconds

AD83.70-P-6001-01A

AD83.70-P-6001-01A



On flame monitor interrogation, the glow pin (A6r2) in its flame monitor function reports a flame prior to the preglow phase.

Replace glow pin (A6r2)



|— —|+



— / / —, |— —| –

Glow pin (A6r2) circuit, short-circuit to positive

Glow pin (A6r2) circuit, open-circuit or short-circuit to ground

AD83.70-P-6001-04A

AD83.70-P-6001-04B



Malfunction lock-out exists:

 Thermal fuse in stationary heater/heater booster unit (A6) has blown because the coolant in the heater unit has exceeded the maximum permissible temperature of 125°C

or

 3 different or the same faults have occurred in sequence

See HHT



|— —| –

 

— / / —, |— —|+

Stationary heater fuel metering pump (Y23) circuit, short-circuit to ground

Stationary heater fuel metering pump (Y23) circuit, open-circuit or short-circuit to positive

AD83.70-P-6001-05A

AD83.70-P-6001-05B

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Overload, |— —|



— / / —

Combustion air blower (A6m2), overload or short-circuit

Combustion air blower (A6m2), open-circuit

AD83.70-P-6001-06A

AD83.70-P-6001-06B



Overload, |— —|



— / / —

Circulating pump (A6m1), overload or short-circuit

Circulating pump (A6m1), open-circuit

AD83.70-P-6001-07A

AD83.70-P-6001-07B



|— —| –

Cable to climate control module, short-circuit to ground

AD83.70-P-6001-08A