Heater booster (ZUH) diagnosis, troubleshooting

AD83.70-P-5002A

Heater booster (ZUH) diagnosis, troubleshooting

13.8.97

 Danger!

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

Do not put stationary heater/auxiliary heater or engine with heater booster into operation in confined spaces or while refuelling. Allow heater unit to cool down after operation and wear safety gloves.

AS83.70-Z-0002-01A

Heater booster (ZUH) diagnosis, advanced information

AD83.70-P-2002A

Stationary heater/heater booster unit, location of components

Model 210 up to 31.05.98

Model 202

Model 210 as of 01.06.98

Model 168

GF83.70-P-0002-03A

GF83.70-P-0002-03B

GF83.70-P-0002-03C

GF83.70-P-0002-03GC

Troubleshooting

Complaint

Possible cause

Note

Remedy

Stationary heater/heater booster unit (A6) does not start

Coolant temperature < 68°C

Outside temperature < 5°C

 Cut-in signal from generator (G2)

 ECT switch (S25/17)

 Air temperature switch (S25/18)

 Stationary heater/heater booster control module (A6n1)

Model 210 as of 01.09.96 up to 28.02.97

AD83.70-P-6002-02A

AD83.70-P-6002-03A

AD83.70-P-6002-04A

Check all actual values with HHT

Stationary heater/heater booster unit (A6) does not start

Coolant temperature < 73°C

Outside temperature < 8°C

 Cut-in signal from instrument cluster (A1)

 Cut-in signal from CDI control module (N3/9)

Model 210 as of 01.03.97 and model 202

Model 168

AD83.70-P-6002-02B

AD83.70-P-6002-02C

Malfunction shut-down at start of heater boost operation with heater unit run-on (approx. 120 seconds) of combustion air blower (A6m2) without repeat start.

 Glow pin (A6r2) in its flame monitor function

 Stationary heater/heater booster control module (A6n1)

Check all actual values with HHT

Combustion starts during the preglow time

 Remains of fuel in combustion chamber due to unsuccessful attempts at starting

 Internal leakage in stationary heater fuel metering pump (Y23)

Allow heater unit to operate for 10 minutes

AD83.70-P-7000-02A

Stationary heater/heater booster unit (A6) does not increase heat output after combustion stabilizes

 Combustion air blower (A6m2)

 Stationary heater fuel metering pump (Y23)

 Stationary heater/heater booster control module (A6n1)

Check all actual values with HHT

Heat output too low

 Combustion air inlet on stationary heater/heater booster unit (A6)

 Routing of coolant lines

 Stationary heater/heater booster control module (A6n1)

Check combustion air inlet for contamination and clean if necessary

Check coolant lines for pinching and kinks and rectify if necessary.

Check all actual values with HHT

Escape of combustion exhaust gases which are sooty or form dense smoke.

 Combustion air inlet on stationary heater/heater booster unit (A6)

 Exhaust emissions value too high

 Fuel delivery quantity

 Combustion air blower (A6m2)

 Stationary heater/heater booster control module (A6n1)

Check combustion air inlet for contamination and clean if necessary

Check and adjust exhaust emissions value with HHT

Model 210 up to 28.02.97:

AD83.70-P-7001-01A

Models 202, 210 as of 01.03.97:

AD83.70-P-7001-01B

Model 168:

AD83.70-P-7001-01C

Check all actual values with HHT

Grey/white combustion exhaust gases (white smoke)

 Exhaust emissions value too low

Check and adjust exhaust emissions value with HHT

Loss of coolant

Grey/white combustion exhaust gases (white smoke)

Exhaust gas odor extremely sweet

 Stationary heater/heater booster unit (A6)

Check heater booster unit for external leaks and replace heater unit if necessary.

Loss of fuel or fuel odor

 Leaks in fuel supply to heater booster unit

Determine leakage point, check stationary heater fuel metering pump, fuel supply lines, connections and stationary heater/heater booster unit for fuel leaks and if necessary seal leakage point or replace component

It is not possible to test the heater booster components with the HHT

No communication between HHT and stationary heater/heater booster control module (A6n1)

 Cables, connections

 Voltage supply

 Diagnostic cable

Check and replace if necessary

AD83.70-P-6002-01A

AD83.70-P-6001-02A