83-403

Coolant circuit with diagram

A. Models 124.061, 124.0 up to approx. 09/92 (excluding models
124.034/036),
models 124.120/128/133/188/193/3 up to approx. 01/93,

models 124.125/127/130/180/185/190/2

The auxiliary heater heating unit (A6) is in

If the mono valve (Y17) in the bypass line is

the full flow of the coolant circuit. In addition,

open, the heat exchanger (6) is separated

a bypass line with electromagnetic mono

from the coolant circuit. The coolant flows

valve (Y17) is installed from the coolant

from the auxiliary heater heating unit (A6)

outlet of the auxiliary heater heating unit

through the bypass line direct to the engine.

(A6) to the coolant return (heat exchanger

This circuit ensures that the engine is heated

outlet).

up more quickly and that no temperature

Function

peaks occur.
If the in-car temperature is more than

If the in-car temperature is more than

approx. 2°C higher than that set at the

approx. 2°C lower than that set at the

temperature selector (e.g. as a result of the

temperature selector, with the auxiliary

sun's rays), the duo and mono valve (Y19/

heater switched on, the duo or mono valve

Y21) of the heat exchanger is closed and the

(Y19/Y21) of the heat exchanger is opened

mono valve (Y17) in the bypass line is

and the mono valve (Y17) in the bypass line

opened. The coolant flows from the auxiliary

is closed. The circulation pump (A6m1)

heater heating unit (A6) through the bypass

pumps coolant from the engine through the

line to the engine (heat exchanger (6)

auxiliary heater heating unit (A6) and heat

disconnected from circuit); only the engine is

exchanger (6) back to the engine.

heated.

At an in-car temperature corresponding to

the temperature set at the selector (

2°C

approx.), the duo or mono valve (Y19/Y21)

of the heat exchanger (6) and the mono

valve (Y17) in the bypass line operate in a

cycle. The cycle sequence is duo or mono

valve (Y19/Y21) of the heat exchanger (6)

open, mono valve (Y17) in the bypass line

closed and vice versa.

Copyright Daimler AG 02.12.14 G/08/07. Ten wydruk WIS nie jest obj

ę

ty funkcj

ą

aktualizacji.

strona 1

Coolant circuit of auxiliary heater

A6

Auxiliary heater unit

a

Inflow from cylinder head

A6m1

Circulating pump

b

Return flow to coolant pump

Y17

Auxiliary heater mono valve

6

Heat exchanger

Y19/Y21

Automatic climate control mono valve, dual
valve

Copyright Daimler AG 02.12.14 G/08/07. Ten wydruk WIS nie jest obj

ę

ty funkcj

ą

aktualizacji.

strona 2