Argo-Hytos SD3EX-B2, Operating Instructions Manual, Page: 19 / 42

Subject to change_SD3EX-B2_SD3EX-C2_14067_1en_06/2022
Page 19
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A sealing ring in the recess behind the thread ensures the valve is sealed in the block and prevents working fluid from leaking out of the block.Sealing
rings on the steel valve housing separate the individual channels in the port from each other. If the ring is not fitted or is damaged, unwanted
interconnection of the channels and unreliable control function of the valve will occur. In this case, the valve must be removed from the port and the
sealing rings replaced with new ones.
› Ensure that no explosive atmosphere is present during the repair (see also 7.5).
› Switch off the pressure source (pump) of the hydraulic circuit (see also 7.5).
› Relieve the hydraulic circuit including the accumulators by connecting it to the tank (see also 7.5)
› Ensure that the hydraulic circuit is de-pressurized (see also 7.5).
› Switch off the electrical supply to the valve solenoids (viz také 7.5).
› Ensure that the surface of the valve and solenoid coils is cooled to a low enough temperature to prevent skin burns (see also 7.5)
› Clean the surface and around valve.
› Loosen the coil nut with a wrench (a = 36) and unscrew it.
› Remove the sealing ring and spool from the valve control system.
› Loosen the valve with a wrench (a = 27) and carefully unscrew it.
› Allow the remaining working fluid from the valve to drain into the prepared smaller container. Dry the valve surface with a cleaning cloth.
› Using a suitable tool, e.g. a small screwdriver, remove any sealing rings. Work carefully, do not damage the valve housing and threads.
Check the valve for damage and cleanliness.
› Use a replacement seal kit. Thread the sealing rings into the recesses one by one in the correct place. Do not confuse the seals! Lubricate the new
seals with grease or working fluid.
› Check the chamber in the block for damage and cleanliness.
› When installing the new replacement valve into the block, follow section 7.2 Product installation.
› After reassembling the coil to the valve control system, check the correct attachment of the coil cable in the grommet and the ground wire to
ensure that they have not come loose during handling.
› After the repair, verify the new seals are tight and the valve is functioning properly.
7.6.2 Replacing the sealing rings on the valve housing
A defective control solenoid coil may only be replaced with the manufacturer‘s original replacement coil with identical parameters.
› Switch off the pressure source (pump) of the hydraulic circuit (see also 7.5).
› Switch off the pressure source (pump) of the hydraulic circuit (see also 7.5).
› Relieve the hydraulic circuit including the accumulators by connecting it to the tank (see also 7.5).
› Make sure that the hydraulic circuit is de-pressurized (see also 7.5).
› Switch off the electrical supply to the valve solenoids (see also 7.5)..
› Ensure that the surface of the valve and solenoid coils is cooled to a low enough temperature to prevent skin burns (see also 7.5).
› Clean the surface and surroundings of the valve.
› Disconnect the coil surface ground wire.
› Disconnect the coil cable from the power supply.
› Loosen the coil fastening nut by turning it anti-clockwise using the wrench a = 36. Remove the nut.
› Remove the sealing ring (1) 21.89x2.62, the coil and the second sealing ring 22x1.5 from the control system tube.
› Check the surface condition of the control system for damage, e.g. corrosion.
› Connect the power supply cable to the new coil according to point 7.2.1, unless a coil with an already connected cable has been supplied by the
manufacturer. We recommend using a new cable to connect the new coil. Replace the sealing rings with new ones. They are supplied in a set with
the coil and a new fastening nut.
› Replace the coil sealing rings with new ones. They are supplied in a set with the coil and a new clamping nut.
› Fit a new 22x1.5 sealing ring, a new coil with attached cable, a new 21.89 x 2.62 sealing ring and screw on a new clamping nut on the control
system tube. Tighten the nut with a wrench to a torque of 5 + 1 Nm.
› Connect the ground wire to the new coil.
› After completing the coil replacement, check the valve for proper operation.
7.6.3 Coil replacement
Hydraulic block Control system
Coil
Mounting nut
Sealing ring (1)
21.89x2.62
Sealing ring (2)
22x1.5