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

Actual values

In contrast to the fault memory the HHT actual values are continuously updated (even during diagnosis) so that faults which occur intermittently for example by shaking components, connectors or the wiring harness can be determined.

Version of control module

Using the HHT the following information can be read out via the control module integrated in the stationary heater:

 Model

 Manufacturing location

 Date of manufacture

 Date code of unit

The following data is available in the HHT actual values submenu:

 Water temperature sensor in °C

 Flame monitor in °C

 Combustion air blower switched on/switched off

Display of instantaneous value of output (in %)

 Stationary heater fuel
metering pump switched on/switched off

Period in ms

 Glow pin switched on/switched off

Display of instantaneous value of output (in %)

 Operating voltage in volts

 Undervoltage limit in volts

 Type of heater unit Gasoline/diesel

 Circulating pump switched on/switched off

Display of instantaneous value of output (in %)

 Vehicle blower switched on/switched off

 Switch Heating/ventilation

In addition with "Thermo Top C" stationary heater:

 STH switch on request switched on/switched off

 ZUH switch on request switched on/switched off

 Heater operation switched on/switched off