MTU 16V4000M*3 series Operating Instructions Manual page 238

Hilzinger preheating unit, side view
1 Flange (supply and return)
2 Junction box
Function
The preheating unit is intended to warm up the engine coolant. The circulation pump (6) ensures the circula-
tion of the preheated coolant through the engine.
The continuous flow heater (4) comprises a heating element. A non-return flap (3) prevents coolant from
flowing through the preheating unit when the engine is running.
When the coolant temperature has reached the value of the thermostat setting (5), the thermostat (5)
switches off the preheating unit via contactors.
In the event of excessive coolant temperature, the temperature limiter of the thermostat (5) opens the con-
trol loop. The preheating unit is switched off.
The unit must be reset manually after the fault has been rectified.
236 | Coolant Circuit, General, High-Temperature Circuit | MS15035/00E 2018-08
3 Non-return flap
4 Continuous flow heater
5 Thermostat
6 Circulation pump