| WARNING Do not service the system alone. Do not reach into parts and assemblies that are AC (mains) powered and live except in the presence of someone who can provide first aid. |
| WARNING Because of the danger of introducing additional hazards, do not install substitute parts or perform any unauthorized modification to the instrument. Return the instrument to a Vaisala office or authorized depot for service and repair to make sure that safety features are maintained. |
| WARNING Do not remove the transmitter module CLT611 from its normal position without first switching off the AC (mains) power. |
| WARNING Do not look at the transmitter module CLT611 of the ceilometer from the beam direction when the transmitter is powered. |
| Before sending your device to service, take a backup of the configuration. The service resets the device and restores default factory settings. |