C 320 CL (203.764) V6-3.2L (112.946) (2004)
Shown On Models 215, 220
Operating procedure
1
Coolant temperature > 65 degrees C and < 77 degrees C
2
Depending on heat requirements, the STH heater or heater booster operates in partial-load or full-load mode:
-
The STH or heater booster fuel metering pump (Y23) and the combustion air blower (A6m2) deliver at their minimum or maximum speeds
and outputs.
-
The coolant circulation pump (A6m1) delivers the coolant via the heat exchanger (2) and the heating and cooling circuits.
-
The ventilation blower delivers pre-heated air to the interior.
3
The STH or heater booster control module (A6n1) monitors the voltage supply internally.
4
The STH or heater booster control module (A6n1) recognizes a fault in the voltage supply:
-
The voltage is < 10.0 to 10.5 V for more than 20 sec.
or
-
the voltage exceeds 15.5 V for more than 6 s.
5
In order to protect the battery or the electrical and electronic heater components, the STH or heater booster control module (A6n1) triggers heater
malfunction delayed switch-off with subsequent malfunction shutoff for approx. 120 s:
-
the STH or heater booster fuel metering pump (Y23) is switched off. and
-
the control and operating module (N18, N22 or N22/7) is actuated via the CAN Class B (CAN B) with the "blower OFF" signal.
6
The control and operating module (N18, N22 or N22/7) switches the vehicle blower off and switches from stationary heating mode to normal
operating mode.
7
Malfunction delayed switch-off has finished:
-
The combustion air blower (A6m2) and the recirculation pump (A6m1) are switched off.