Testing a speed though water instrument transducer

[Chuck - Raymarine - Moderator]

Testing a speed though water instrument transducer

To test a speed through water instrument transducer:
- Verify that the transducer’s paddle wheel is free of marine growth and rotates freely on its shaft
- Ensure that the Speed detecting instrument, iTC-5, or pod is powered
- Disconnect the GREEN transducer lead from the instrument display or instrument pod.
- Connect a multimeter to the GREEN and SHIELD transducer leads and configure the multimeter to measure continuity or resistance.
- Slowly rotate the transducer paddle wheel by hand. Note that as the paddlewheel is rotated, the multimeter should alternate between an open circuit and a closed circuit with each quarter turn. As such one complete revolution of the paddle wheel should open and close the circuit four times.

Should the multimeter respond as indicated above, then the speed sensor element of the transducer would be deemed operational and the instrument/instrument pod/iTC-5 should be replaced or sent to Raymarine’s Product Repair Center to be bench checked / serviced. Should the multimeter not respond as indicated above, then the speed sensor element of the transducer would be deemed to not be operational and the transducer should be replaced. Should the housing be in good shape, then it would be recommended that Gemeco (Airmar's US distributor) be contacted to order a replacement speed/temp insert for the model of instrument transducer which is installed onboard the vessel

RAYFAQ#