Monovalve

Monovalve With Check Valve, Electric Recirculating Pump, Diagram For Coolant Circuit And Cold Engine Lock

Monovalve (11) controls the coolant flow through heat exchanger. The valve comprises a magnetic valve which is continuously connected to plus via terminal 15. Opening and closing times are controlled by electronic switching unit for temperature control via minus. If plus and minus are connected the valve is closed.

The opening or closing time depends on the respective deviation from actual to desired temperature.

During controlled operation, the monovalve opens and closes in a 5-second cycle.






When the engine is shut off (monovalve "open") the check valve (arrow) installed in monovalve makes sure that the heat exchanger is not filled up with hot coolant.

Layout of monovalve with recirculating pump






11 Monovalve
30 Recirculating pump

The temperature switch (2) (cold engine lock) prevents starting of system at a coolant temperature below 35°C in functions "c" and "d" and thereby makes sure that no cold air is blown against passengers during the winter.






Layout of temperature switch (cold engine lock) on 8-cylinder models
2 Temperature switch

The recirculating pump (30) is located adjacent to monovalve (11) and serves to maintain a uniform coolant flow through heat exchanger (b) also at low engine speeds (Fig.) During controlled operation, the pump is switched on by signal "footwell flaps". Electric activation is by way of control unit.






Diagram of coolant circuit
1 Surface heat exchanger (starting 11/81)
2 Thermovalve (starting 11/81)
11 Monovalve
30 Recirculating pump
b Heat exchanger
c Return flow
d Forward flow