Troubleshooting - Hilti DD 30-W Manual

7.1 Replacing the carbon brushes
WARNING
Risk of injury due to electric shock !
▶ The machine may be operated, serviced and repaired only by trained, authorized personnel. This
personnel must be specially informed of any possible hazards.
The carbon brushes must be replaced when the indicator lamp with the wrench symbol lights.
1. Unplug the supply cord from the power outlet.
2. Open the carbon brush covers on the left-hand and right-hand sides of the motor.
3. Take note of how the carbon brushes are fitted and how the conductors are positioned. Remove
the worn carbon brushes from the diamond core drilling machine.
4. Fit the new carbon brushes, positioning them exactly the same as the old ones fitted previously.
Take care to avoid damaging the insulation on the indicator lead as you insert the brushes.
5. Screw on the carbon brush covers on the left- and right-hand side of the motor.
6. Run in the carbon brushes by letting the machine run under no load for at least 1 minute without
interruption.
➥ The indicator lamp will go out after a running time of approx. 1 minute with the new carbon brushes.
7.2 Cleaning the water flow sight glass
Pay attention to cleanliness at your workplace when cleaning the sight glass. Take care to prevent dirt
entering the inside of the water flow rate indicator while the glass is being cleaned.
1. Use a Torx TX 15 screwdriver to remove the two screws at the sight glass.
2. Lift the glass away.
3. Remove the water flow rate impeller, complete with axle.
4. Remove any dirt particles by flushing under running water.
5. Before fitting the parts, check the sight glass seal for damage and replace it if necessary.
6. Make sure that the seal is positioned exactly in its seat. The seal may otherwise be pinched between the
plastic parts when the sight glass is fitted, thereby damaging the seal and resulting in leakage.
7. Refit the impeller complete with its axle.
8. Press the sight glass back into place.
9. Insert the sight glass retaining screws (Torx screws) and tighten them securely.
8

Troubleshooting

If the trouble you are experiencing is not listed in this table or you are unable to remedy the problem by
yourself, please contact Hilti Service.
8.1 The diamond core drilling machine is in working order
Malfunction
The service indicator lights.
*2048398*
Printed: 05.07.2019 | Doc-Nr: PUB / 5283523 / 000 / 06
Possible cause
The carbon brush wear limit has
almost been reached. The diamond
core drilling machine will continue
to run for a few hours until it shuts
down automatically.
The carbon brushes have been
changed and must be run in.
2048398
Action to be taken
▶ Have the carbon brushes
replaced at the next opportunity.
▶ Run in the carbon brushes by
letting the machine run under
no load for at least 1 minute
without interruption.
English 19