Zenit Group | 28 Mar 2018
UNIQA - ZUG GR WET
Assembly - Complete mechanical seal dismantling and oil change procedure for Zenit UNIQA submersible pumps.
Models with grinding system (ZUG GR) in WET version. Type DR1-D mechanical seals.
- Fit the rotation stop pin into the seat in the sealing flange and fix it with Loctite 641 threadlocker
- Fit the O-ring into place on the flange
- Fit the flange on the seat using a suitable driver and secure it with the snap ring, making sure it is perfectly snug
- With a felt-tip pen, mark the position of the pin on the flange and that of the relative seat in the counterface
- Wet the counterface with alcohol and fit it, aligning the marks
- Fit the counterface with a suitable driver
- Blow with compressed air to remove all traces of dirt and lubricate the counterface
- Clean the surfaces of the seal with a paper towel
- Fit the seal onto the shaft
- Grease the O-ring and fit it into the seal seat
- CAUTION to avoid damaging the seal, do not use metal tools
- Fit the case, aligning the slots correctly, and position it with the relative driver, which ensures the correct preload on the seal
- Tighten the 3 stud bolts, securing them with Loctite 243 threadlocker
- Remove the driver. Use an extractor screw if necessary
- Grease the seal and fit it onto the casing, taking care to position the slots correctly
- Fit the rotation stop pin into the seat in the pump plate and fix it with Loctite 641 threadlocker
- Wet the counterface with alcohol and fit it into the seat in the pump plate, positioning the pin and slot correctly
- Fit the seal with a suitable driver
- Clean the surface of the counterface with a paper towel
- Fit the counterface locking ring and fit the screws without fully tightening them. Use Loctite 243 threadlocker
- Lift the three wings of the ring and set them at an angle of about 60°, taking care that they do not interfere with rotation of the seal
- Fit the O-ring into the seat in the pump plate
- Fit the O-rings into the oil chamber screw seats
- Spray the seal with spray lubricant
- Fit the pump plate onto the oil chamber and fix it with the screws
- First tighten the screws by hand to fit it gradually into position.
- Fit a cap into one oil chamber hole and a compressed air fitting into the other
- Pour in a little alcohol to check for leaks
- Test for tightness at a maximum pressure of 1 bar
- Remove the cap and fitting
- Refit the handle so that the cable will not be crushed when handling the motor
- Lay the motor part horizontal on the workbench with the oil chamber caps upward
- Tighten the handle screws
- Fill the chamber with oil. Refer to the documentation for the correct amount
- Seal the oil chamber with the caps
- Place the impeller on the support
- With a hoist, lift the motor by the handle
- Fully tighten the impeller fixing screw. This is temporary.
- DO NOT use threadlocker!
- Place the pump on the workbench horizontal, taking care not to damage the impeller blades
- Measure the gap between the pump blade and plate with a gauge
- Measure the pump body height with a gauge
- Apply shims as necessary to obtain a clearance of 0.2 - 0.5 mm
- Remove the impeller fixing screw
- Fit the paper seals
- Mount the pump body and secure it with the fixing screws
- Use a feeler gauge to check that the impeller clearance is correct
- Fit the chopper plate
- Fit the chopper knife, using shims as necessary.
- Tighten the chopper knife fixing screw and secure it with Loctite 270 threadlocker
- Use a feeler gauge to check the clearance between the chopper plate and knife. Correct clearance 0.2 - 0.5 mm