Hilti DD 30-W Original Operating Instructions page 50

• Do not operate the machine if damaged or if its parts malfunction. Have the machine repaired by Hilti
Service immediately.
• On versions with a replaceable supply cord, the supply cord may be replaced by a trained electrical
specialist.
• After cleaning and maintenance, fit all guards or protective devices and check that they function correctly.
Note
To help ensure safe and reliable operation, use only genuine Hilti spare parts and consumables. Spare
parts, consumables and accessories approved by Hilti for use with the product can be found at your
local Hilti Center or online at: www.hilti.com
7.1 Replacing the carbon brushes
DANGER
Risk of injury! Risk of 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.
Note
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.
Note
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
Note
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.
42 English
Printed: 20.12.2016 | Doc-Nr: PUB / 5283477 / 000 / 03