➤ The coolant should be mixed in the proportions specified by the manufacturer.
Coolant mixture table:
Proportions [% vol.]
Frost protection to approx. [°C]
Anti-corrosion agent/anti‐
freeze
Water
50
50
−37
Tab. 93 Coolant mixture table
Never use a higher concentration than 55% vol. of anti-corrosion agent/antifreeze, even at
extremely low ambient temperatures. Maximum frost protection is achieved with 55% anti-
corrosion agent/antifreeze. This corresponds to frost protection down to approx. –45°C.
The concentration of antifreeze should not be less than 33%, as corrosion protection can no
longer be guaranteed and heat transfer properties deteriorate below this point!
10.3.1.4 Filling/replenishing the coolant
In order to ensure optimal frost and corrosion protection, and to prevent the build-up of residue
(sludge) inside the cooling circuit, the proportion of antifreeze in the coolant must not fall below
33%. Replenishing solely with water dilutes the antifreeze concentration and is therefore prohibi‐
ted.
Ensure that there is sufficient space for the coolant to expand without overflowing when hot.
Precondition The negative cable to the battery is disconnected.
1. Loosen and remove the coolant expansion tank filler cap.
2. Mix a quantity of coolant as per the table and replenish to the level indicated.
Replenish the coolant to just below the
maximum mark
A
.
3. Close the filler cap.
4. Connect the negative cable to the battery.
5. Shut the enclosure.
6. Start the engine and allow to run in IDLE for about 1 minute.
7. Stop the drive engine.
8. Open the enclosure.
9. Check the coolant level.
If the coolant level in the expansion tank has decreased: Replenish the coolant.
10. Visually inspect for leaks.
11. Shut the enclosure.
10.3.1.5 Draining the coolant
Precondition The machine has cooled down.
The negative cable to the battery is disconnected.
10 Maintenance
10.3 Drive engine maintenance
104
Operating Manual Portable Rotary Screw Compressor
MOBILAIR M27 PE
No.: 9_9548 22 HCE
