Instructions
AKS 38

AKS 38 Level Controller

Refrigerants
The AKS 38 can be used for all common non-flammable refrigerants, including R717 and non-corrosive gases/liquids dependent on sealing material compatibility.
Flammable hydrocarbons are not recommended.
Temperature range
-50°C/+65°C (-58°F/149°F)
Pressure range
AKS 38 is designed for a max, working pressure of 28 bar g (406 psig)
IMPORTANT
IG Should pressure testing in excess of 28 bar g (406 psig) be necessary then the internal float assembly must be removed, thus allowing a maximum test pressure of 42 bar g (609 psig)
Electrical data

• Change-over Micro (SPDT) switch
• 250 Vac/10 A
• 30 V d.c/5A
• DIN Plug
• DIN 43650 connection
• PG 11, 8-10 mm (0.31″-0.39″)
• Screw terminal 1.5 mm² (16 AWG)
• 3+PE

Liquid level differential
Variable between 12.5 mm to 50 mm (1½” to 2″) in 12.5 mm (1/2″) increments.
Required differential setting should be made prior to installation.
Factory set at 50 mm (2″).
Enclosure
IP 65

Installation

IMPORTANT
AKS 38 must always be installed in a vertical position (fig. 1 and 2).
AKS 38 is supplied complete with flanges (fig 2, pos. 14). The external surfaces of the flanges must be prevented against corrosion with a suitable protective coat after installation.
To avoid an oil seal forming which would affect the movement of the internal float the bottom connecting pipe must have an incline towards the liquid separator.
Shut-off valves should be mounted as close as possible to the float for service (fig. 1).
Switch point
The switch point is relative to the actual liquid level marking on the AKS 38 housing. See fig 7.
The upper switch point is actually (D: 2) higher than the actual liquid level marking.
The lower switch point is actually (D: 2) lower than the actual liquid level marking. Where D differential.
Adjusting the liquid level differential switch point (see fig. 9)
The float comes factory set with a differential setting of 50 mm (2″) with the lower locking ring C in position b. To acheive smaller differential settings reposition the lower locking ring C at b, 37.5 mm (1½”); (b225 mm (1″); b = 12.5 mm (½”). The upper locking ring C in position a should not be adjusted or repositioned.
IMPORTANT
The adjustment must be made before AKS 38 is installed in the refrigeration system. Use two thumbs for repositioning the locking rings. Do not use any tools.
Remove the AKS 38 switch box (fig. 3, pos. 2).

• Unfasten the M4 x 8 (fig. 3, pos. 3) pinol tailstock screw with a Allen key.
• Remove the switch box by slowly easing upwards.

Remove the AKS 38 housing top cover (fig. 3, pos. 4).

• Unfasten the 4 x M12 x 35 stainless steel bolts (fig. 3, pos. 5).
• Remove the complete top cover including installed pressure tube (fig. 3, pos. 7).

Remove the complete float assembly (fig.3, pos. 1 and fig. 4, pos. 1) from the AKS 38 housing (fig. 3, pos. 6).

• Reposition the lower locking ring at the required differential setting.
• See fig. 8 and fig. 9.

Reassembly

• Refit the float assembly back into the AKS 38 housing (fig. 3, pos. 6).
• Reinstall the complete top cover (fig. 3, pos. 4) and fasten the 4 x M12 x 35 bolts (fig. 3, pos. 5).
• Max. tightening torque: 74 Nm (100 ft-lb).
• Reinstall the switch box (fig. 3, pos. 2) by slowly forcing it down over the pressure tube (fig. 3, pos. 7).
• Position the switch box (fig. 3, pos. 2) as required and fasten the M4 x 8 pinol tailstock screw (fig. 3, pos. 3) with a Allen key.

Electrical installation
Make electrical connection to DIN plug using cable with maximum 4 cores and wire in accordance with wiring diagram (fig. 8).

1. Common
2. Normally Closed
3. Normally Open Earth terminal

Maintenance

IMPORTANT
The AKS 38 must be evacuated before opening to air.
Replacing the internal float assembly (fig. 3, pos.1)

• Unscrew the stainless steel bolts 4xM12x35 (fig. 3, pos. 5).
• Remove the top cover (fig. 3, pos. 4) including installed pressure tube (fig. 3, pos. 7) and switch box (fig. 3, pos. 2).
• Remove the internal float assembly (fig 3, pos. 1).
• Install the new float assembly.

Replacing the flange gaskets (fig. 2, pos. 15)

• Unscrew the 4 x M12x35 stainless steel bolts on the side flange (fig. 2, pos. 13).
• Unscrew the 4x M12x35 stainless steel bolts on the bottom flange (fig. 2, pos. 13).
• Remove both gaskets (fig. 2, pos. 14).
• Install the new gaskets.
• Fasten 4 x M12×35 stainless steel bolts in each flange. Max. tightening torque: 74 Nm (100 ft-lb).

Replacing the top cover gasket (fig. 3, pos. 8)

• Unscrew the 4x M12xx35 stainless steel bolts (fig. 3, pos. 5).
• Remove the top cover (fig. 3, pos. 4) including installed pressure tube (fig. 3, pos. 7) and switch box (fig. 3, pos. 2).
• Remove the gasket (fig. 3, pos. 8).
• Install the new gasket.
• Fasten 4 x M12×35 stainless steel bolts (fig. 3, pos. 5). Max. tightening torque: 74 Nm (100 ft-lb).

Replacing the aluminium gasket (fig. 3, pos. 11)

• Unscrew the M4 x 8 pinol tailstock screw (fig. 3, pos. 3) with a Allen key.
• Remove the switch box (fig. 3, pos. 2) by slowly easing upwards.
• Unscrew the pressure tube (fig. 3, pos. 7) with a 32 mm wrench.
• Remove the aluminium gasket (fig. 3, pos. 11).
• Install the new gasket.
• Reinstall the pressure tube.
• Reinstall the switch box.

Replacing the switchbox (fig. 3, pos 2)

• Remove the DIN-plug (fig. 6).
• Unscrew the M4 x 8 pinol tailstock screw (fig. 3, pos. 3) with a Allen key.
• Remove the switch box (fig. 3, pos. 2) by slowly easing upwards.
• Install the new switch box.

Replacing the O-ring at the pressure tube (fig. 3, pos. 9)

• Unscrew the M4 x 8 pinol tailstock screw (fig. 3, pos. 3) with a Allen key.
• Remove the switch box (fig. 3, pos. 2) by slowly easing upwards.
• Remove the O-ring.
• Install the new O-ring.
• Reinstall the switch box.

DECLARATION OF CONFORMITY
The Pressure Equipment Directive 97/23/EC
Name and Address of Manufacturer within the European Community
Danfoss Industrial Refrigeration A/S
Stormosevej 10
PO Box 60 DK-8361 Hasselager
Denmark
Description of Pressure Equipment
Refrigerant Float Switch
Type AKS 38

Conformity and Assessment Procedure Followed

Name and Adress of the Notified Body which carried out the Inspection
TÜV-Nord e.V.
Grosse Bahnstrasse 31 22525 Hamburg, Germany

(0045)
Name and Address of the Notified Body monitoring the Manufacturer’s Quality Assurance System
TÜV-Nord e.V.
Grosse Bahnstrasse 31
22525 Hamburg, Germany
References of Harmonised Standards used
EN 10028-3
EN 10213-3
EN 10222-4
LVD 73/23/EEC
References of other Technical Standards and Specifications used
DIN 3840
EN/IEC 60730-2-16
AD-Merkblätter
Authorised Person for the Manufacturer within the European Community
Name: Morten Steen Hansen
Title: Production Manager
Signature:
Date: 10/01/2003

RI5MA352 ©
Danfoss A/S (RC-CMS/MWA), 03 – 2004

Documents / Resources

Danfoss AKS 38 Level Controller [pdf] Instructions 38, 148R9524, AKS 38 Level Controller, Level Controller

References

• User Manual