Fig. 40 Checking coolant level
1
Coolant level
A
Maximum check mark (FULL)
B
Minimum check mark (LOW)
2
Coolant equalising tank
3
Water cooler
4
Overflow
5
Filler neck with cap
1. Check the level of coolant in the expansion tank.
Top up when the coolant level falls below the
minimum check mark
B
: Replenish the coolant.
2. Close the door.
Have the cause for the coolant loss determined and rectified.
10.4.1.2 Checking the coolant
The coolant should be checked according to the maintenance schedule to ensure quality and op‐
erational life.
Coolant quality can be determined by the following parameters:
■ Visual check
■ Antifreeze concentration measurement
➤ Unscrew and remove the expansion tank filler cap
5
.
Visual check
The coolant should be checked for its colour and any particles or sediments floating in it.
➤ Take a coolant sample and analyze.
The coolant is discoloured and/or has contains floating particles. Change the coolant.
Antifreeze concentration measurement
An instrument (e.g. refractometer) is used to check antifreeze concentration.
Maximum frost protection is ensured with an antifreeze concentration of 55% by volume, as frost
protection and heat transfer properties deteriorate beyond this point. Higher concentration also
leads to higher operating temperature.
10 Maintenance
10.4 Engine maintenance
106
Operator Manual Screw Compressor
M114 SIGMA CONTROL SMART
No.: 901765 05 USE
