STH switchover valve component description - GF83.70-P-4205T

MODEL 211.0/2/6 with CODE (228) Stationary heater

Shown on model 211.2

Fig 1: Locating STH Switchover Valve

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

Location

The switchover valve on the STH heater unit (A6) is located in the front area of the right wheel well.

Function

The switchover valve is a solenoid valve which, depending on actuation from the STH control unit (A6n1), regulates the flow of coolant (large or small coolant circuit).

Coolant temperature less than 60°C (heater operation started)

The switchover valve is permanently actuated and thus only releases the small coolant circuit.

Coolant temperature as of 60°C (heater operation started)

The switchover valve is actuated by pulses. With this, the large coolant circuit is also heated.

No heater operation:

The switchover valve is opened (not actuated) and releases the large coolant circuit.