Zenit Group | 28 Mar 2018

UNIQA - ZUG GR WET

Assembly - Complete mechanical seal dismantling and oil change procedure for Zenit UNIQA submersible pumps. The procedure also involves adjustment of the impeller and chopper knife clearance. Models with grinding system (ZUG GR) in WET version. Type DR1-D mechanical seals.

Step by step operations

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