If a customer wishes to lower the set point of the jacket heaters on MTU OE gensets, for example to lower the base
standby load of the installation, then there will normally be a Limit alarm in the ECU that will trigger if the temperature falls too low.
Meaning that less than 32degC will trigger a yellow alarm.
A slightly higher setting on the
preheater itself would normally be required to maintain 32degC HT temp, something that would have to be
tested but likely 35degC at least in this example.
Further information can be found in the MTU operating manual, for example for 12/16V4000Gx3 (M015710/10E):
When setting maximum preheater limits also be aware that hotspots in the cooling system can result in temperatures significantly higher than the setpoint so caution and awareness of the cooling system design must be used.