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Fig. 38 Checking the coolant level
1
Coolant level
A
Maximum mark (FULL)
B
Minimum mark (LOW)
2
Coolant expansion tank
3
Fan casing
4
Overflow
5
Filler neck with cap
1. Check the level of coolant in the expansion tank.
When the coolant level falls below the
minimum mark
B
: Replenish the coolant.
2. Close the door.
Determine the cause for the coolant loss and rectify.
10.4.1.2 Checking the coolant
The coolant should be checked in line with the maintenance schedule to ensure quality and long
service life.
Coolant quality can be determined by the following parameters:
■ Visual check
■ Measuring the concentration of the antifreeze
➤ Unscrew and remove the expansion tank filler cap
5
.
Performing a visual check:
The coolant should be checked for discolouration and any floating particles (flocculation).
➤ Take a coolant sample and analyse it.
If the coolant is heavily discoloured and/or contains floating particles: Change the coolant.
Measuring the concentration of the antifreeze:
An instrument (e.g. refractometer) is used to check the antifreeze concentration of the coolant.
Maximum frost protection is ensured with an antifreeze concentration of 55% volume, as frost pro‐
tection and heat transfer properties deteriorate beyond this point. A higher concentration also leads
to higher operating temperatures.
10 Maintenance
10.4 Drive engine maintenance
120
Operator Manual Portable Rotary Screw Compressor
MOBILAIR M82 SIGMA CONTROL SMART
No.: 901783 08 USE