
Operating instructions_PRM2X2-06_15313_1en_08/2023
Page 19
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7.5 Extraordinary and emergency situations
In the event of a power failure to the solenoids or a coil failure, the centering spring will return the valve spool to its base position.
Based on the results of the risk analysis, the following potential faults have been identified:
› External valve leakage due to seal damage associated with a working fluid leak.
› Loss of valve function, resulting in loss of control of the appliance.
› Mechanical damage to the electrical part of the valve, including the cable.
DANGER
Shutdown of electrical power, pressure source and circuit relief
In the event of an emergency, immediately shut off the electrical power supply to the control solenoids and
the pressure source (pump). Relieve all parts of the hydraulic circuit including the hydraulic accumulators by
connecting them to the tank. A malfunctioning valve may cause a dangerous operating situation due to loss
of control. A damaged electrical part can initiate an explosion.
DANGER
Prohibition of handling and repair in explosive atmospheres
A defective valve must not be repaired or dismantled when an explosive atmosphere is present.
There is a risk of initiating an explosion.
WARNING
Check pressure relief part of the circuit
Always ensure that the circuit is depressurised before intervening in the hydraulic circuit, for example before
removing a valve. Otherwise there is a risk of leakage of working fluid and contamination of persons.
WARNING
Surface temperature
Before starting disassembly, make sure that the surface of the valve and solenoid coils has cooled to a low
enough temperature to prevent skin burns.
Defective valves must be replaced/repaired.
ENVIRONMENTAL PROTECTION
Spilled working fluid must be removed immediately, e.g. with suitable absorbents, contaminated parts of the perimeter cleaned,
contaminated objects in the vicinity cleaned or disposed of. Contaminated objects and residues of leaked working fluid must be
disposed of in accordance with the applicable environmental regulations.
FIRST AID
Electric shock
› Switch off the power supply immediately
› Make sure the casualty is breathing.
› Call emergency medical services
› If the casualty is not breathing, initiate measures to restore basic life functions according to first aid abilities (CPR, artificial
respiration) and equip the workplace (defibrillator) with life-saving equipment.
Contamination by hydraulic working fluid
If contamination of persons occurs, contaminated parts of clothing must be removed immediately and the skin thoroughly washed
with soap or treated with a suitable cream.
If the eyes are contaminated, flush them with clean water and seek medical attention. Seek medical attention also in case of
accidental ingestion of working fluid or skin allergic reaction to splashes of working fluid.
7.6 Repairs carried out by specialist
A suitably qualified user is authorised to replace the complete valve, the seals at the base of the valve body, which are supplied as a spare set.
A defective valve must be removed and replaced with a new one. Repairs to a defective valve may only be carried out by the manufacturer.
When replacing the defective valve with a new one, proceed as follows:
› Ensure that no explosive atmosphere is present during the repair period. (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 pressure-free (see also 7.5).
› Switch off the electrical supply to the directional control 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).
› Disconnect the electrical supply cable to the coils (see 7.6.3).
› Clean the surface and surroundings of the dirctional control valve.
› Loosen and unscrew the four fastening screws M5x45 DIN 912 using the allen key A/F 4. Carefully remove the valve from the connection plate.
› Allow the remaining working fluid from the valve to drain into the prepared smaller container.
› When installing the new replacement valve, follow section 7.2 Product installation.
Remove residual working fluid from the dismantled defective valve, seal the ports with a shipping plate and package it to prevent mechanical damage
and contamination of the area outside the package during transport. Send the packaged valve with a description of the manifestation of the defect
to the manufacturer. A new valve is warranted by the manufacturer for 1 year. However, a claim may not be accepted by the manufacturer if the
valve is mechanically damaged, the seal material is damaged by aggressive liquid, or the valve has been shown to have been used improperly and not
in accordance with these instructions of use.
7.6.1 Replacing a defective valve