GF83.70-P-4200LE STH Control Unit, Component Description

GF83.70-P-4200LE STH Control Unit, Component Description
- with CODE (228) Stationary heater

Component Identification:

Location
The STH control unit is integrated in the STH heater unit (A6) (model 216) or in the STH or HB [ZUH] heater unit (A6) (model 221), which is located in the rear area of the right wheel arch.

Task
The STH control unit has the following tasks:
^ Reading in of sensors and signals
^ Evaluation of input factors
^ Actuation of components

Reading in of sensors and signals
The input factors are read in with the following connections:
^ Direct line
^ Interior CAN

Direct line
The following signals and sensors are read via a direct line:
- STH radio remote control receiver (A6/1)
- Temperature sensor (A6b1)
- Thermal fuse (A6f1)
- Glow pin unit flame monitor (A6r4)

If a temperature of T = 125 �C is exceeded in the STH heater unit, the thermal fuse detects overheating and triggers the heater unit fault run-on process for approx. t = 120 s followed by fault interlock.

Interior CAN
The signals are read in by the STH control unit via the interior CAN.
The resulting functions are described in the relevant function descriptions (see block diagram or function schematic).

Evaluation of input factors
The input factors that have been read in are evaluated by the integrated microprocessor and the relevant components are then actuated.

Actuation of components
Components are actuated with the following lines:
^ Direct line
^ Interior CAN

Direct line
The following components are actuated via a direct line:
- Combustion air blower (A6m2)
- Fuel preheating system (A6r5) (with diesel engine)
- STH switchover valve (Y16)
- STH fuel metering pump (Y23) (model 216) or STH or HB [ZUH] fuel metering pump (Y23) (model 221)
- STH radio remote control receiver

Interior CAN
The signals are transmitted by the STH control unit via the interior CAN.
The resulting functions are described in the relevant function descriptions (see block diagram or function schematic).

Variants
- Gasoline version
- Diesel version