Oil Check And Change In The Mechanical Seal Chamber; Checking Parts Subject To Wear; Checking The Bearings; Coupling Parts - Zenit DGN 250/2/G65V A1DM/50 Manuel D'utilisation Et D'entretien

5.1 OIL CHECK AND CHANGE IN THE MECHANICAL SEAL CHAMBER

Before inspection and maintenance operations, carefully read and apply the safety procedures indicated in paragraphs 1.2 and 1.3
The oil should be changed every 5000-7000 working hours, or at least once a year.
Proceed as follows:
- Position the electric pump horizontally;
- Unscrew the plug and drain off the oil into a suitable container, or use an oil aspiration device.
- If there is no water in the oil, then the mechanical seal is still in good condition and the chamber can be refilled with fresh oil.
- if small amounts of water are found on the bottom of the chamber, this is due to condensation collecting there; this should be
considered a normal occurrence, not the result of a faulty mechanical seal;
- If a substantial quantity of water has entered the oil chamber and contaminated the oil, this indicates that the mechanical seal
needs inspecting, and perhaps replacing;
- If the seal should require replacing, this must be carried out by a specialised centre;
- Refill the chamber completely with biodegradable oil such as CASTROL PRODUCT L 320 or similar; when full, extract 8% of
the total oil so that there is a suitable air cushion in the chamber, making sure however that the minimum level is not below 80%.
- Once the operations outlined are complete, tighten the plug and refit the electric pump.
If none of the above is available, common Vaseline oil can be used as an exception. For any maintenance/repairs required, contact
our nearest service centre.
Any repairs to the electric pump must be carried out by the manufacturer or by specialist personnel. If this is not respected, the
guarantee will be invalidated and the machine may become unsafe.
Safe operation of the mechanical seals: the device's working life is estimated at 7000 hours in non-standard operating conditions
(dry or by liquids with a high waste content) or 20,000 hours of use in normal operation conditions, after which it must be replaced.
During maintenance operations, replace the seals and o-rings if worn or not in perfect working condition.

5.2 CHECKING PARTS SUBJECT TO WEAR

Before inspection and maintenance operations carefully read and apply the safety procedures indicated in paragraphs 1.2 and 1.3
During programmed maintenance operations, or any time pump performance is reduced, or vibrations and noise increase, the
hydraulic parts subject to wear must be checked and, if necessary, replaced. We recommend that any parts replaced must be
replaced with official ZENIT spare parts. All special maintenance operations must be performed by the manufacturer, using official
parts, particularly where the EX versions are concerned. In the event that the hydraulics become partially or totally blocked, they
should be cleaned thoroughly with a jet of high pressure water. If the hydraulic part needs to be removed and refitted, refer to the
blow/up in fig. 2 - 2/a.

5.3 CHECKING THE BEARINGS

The bearings will operate safely for an estimated 20,000 working hours, after which they must be replaced
Check the condition of the bearings every 7000 hours or every working year. If signs of wear or increased noise levels are detected,
proceed with their replacement.

5.4 COUPLING PARTS

- ISO 4014 hexagonal-head screws
- ISO 4032 nuts
- ISO 4759/ 1 hollow cylindrical screws
- ISO 4753 dowels
The tools required for maintenance are supplied with the device (wrenches for cylinder or round-head socket screws).
When replacing screws, nuts or dowels, use A2-70 screws and bolts.

5.5 MAIN PARTS

5.5.1 COOLING JACKET

To assemble the cooling jacket, first fit it in the frame until it reaches the intermediary support. Then fit the housing support on the
top and fasten it with screws. Removal of the upper ring is facilitated by the two spot-faced, threaded holes into which the two
screws are fitted.

5.5.2 MECHANICAL SEALS

a pin wrench is required for fitting and removing the fastening ring nuts on the seals.

5.5.3 TIGHTENING THE ROTOR (2 poles)

The rotor is keyed onto the shaft by means of a tapered coupling. When fitting the rotor, no axial adjustments are required, but the
top screws, which can be M8/M10, must be tightened; a tightening torque of 20 Nm is required for M8 screws and 40 Nm for M10
screws. The rotor is disassembled by removing the top screw, then extracting the rotor by screwing an M12 screw into the
(extractor) hole. To prevent damaging the thread on the top of the shaft, insert a spacer into the threaded hole.
5.5.3.1 PUMP BODY (2/poles)
To guarantee the axial shim between the rotor and the pump body, use shimming seals between the pump body and intermediate
support.
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