AHE test of electrical system flame monitor open circuit

AD83.70-W-6000-37A

AHE test of electrical system flame monitor open circuit





Scope of test

Measuring instrument/

Test connection

Operation/Requirement

Specified value

 Possible cause/Remedy

1.0



Flame monitor –//–

Supply cable /

Internal resistance

E2 

Z14



 E4

Ignition: OFF

Heater unit: OFF

Run-on phase must have ended.

Disconnect plug connection E on control unit (behind timer).

Carry out measurement at connection plug E.

2.53.5 Ω

(at approx.
25 °C)

Value in order:

 1.1

Value > 30 kΩ:

 Plug connection / cable –//–

 1.4

1.1

Flame monitor –//–

Supply cable

E2

Z14



E4

Ignition: OFF

Heater unit: OFF

Re-connect plug connection E on control unit (Z14).

Connect volt meter to plug connection E.

Ignition: ON

Heater unit: ON

Maintain measured value (up to max. 90s after switching on heater unit).

150300 mV

Value > 300 mV:

 1.2

Value in order:

 Possible loose contact:

Erase fault memory and tap / shake plug connections. Cause of fault is located in area where fault code  re-appears.

 If no fault can be determined, replace control unit (Z14) on trial.

1.2

Flame monitor –//–

Control unit

E2

Z14



E4

Ignition: ON

Heater unit: ON

Connect voltmeter to plug connection E.

Heater unit: OFF

Value > 300 mV:

 1.3

Value < 100 mV:

 Replace control unit (Z14) on trial.

1.3

Flame monitor –//–

Interfering voltage

Flame monitor circuit

E2

Z14



E4

Ignition: ON

Connect voltmeter to plug connection E.

Ignition: OFF

Value > 300 mV:

 Replace control unit (Z14) on trial, if voltage on voltmeter falls to approx.
0 V when control unit disconnected.

 Cable (measured value 22.5-29.5V remains, short-circuit or cable-short to terminal 30)

Value < 100 mV:

 Cable (short-circuit or cable-short to terminal 15)

1.4

Flame monitor –//–

Supply cable

14/8

FF8





14/9

Ignition: OFF

Re-connect plug connection E on control unit.

Connect short-circuit bridge to plug connection FF8 under electrical compartment.

Ignition: ON

Heater unit: ON

If fault code  appears:

 1.5

If fault code  re-appears:

 Plug connection / cable –//–

 Inspect cables in cable harness from control unit (Z14) to electrical compartment, fit new cable if necessary (use 1 mm2, green/yellow).

1.5

Flame monitor –//–

Supply cable

14/8

G





14/9

Ignition: OFF

Connect short-circuit bridge to plug connection G under air recirculation box.

Ignition: ON

Heater unit: ON

If fault code  appears:

 1.6

If fault code  re-appears:

 Plug connection / cable –//–

 Inspect cables in cable harness from air recirculation box to electrical compartment, fit new cable if necessary (use 1 mm2, green/yellow).

1.6

Flame monitor –//–

Internal resistance

a 

X8



 b

Ignition: OFF

Tip cab and remove heater unit (take care not to disconnect coolant circulation), if necessary refer to 

AD83.70-W-2000-16A

 Danger!

Risk of injury and of scalding with high coolant temperature!

AS83.70-Z-0002-01A

AS20.00-Z-0001-01A

Disconnect plug connection on heater unit.

Carry out measurement directly on plug X8

AD83.70-W-2000-18A.

Value 2.53.5 Ω:

 Inspect plug connections, replace cable harness from air recirculation box to heater unit complete with molded connection plate on heater unit if necessary.

Value > 20 Ω:

 Inspect plug X8 (corrosion), replace flame monitor complete with cable and plug X8 if necessary.