I have a Volvo Penta QL bow thruster that i purchased from a Volvo Penta Dealer that is faulty. I called on my local Volvo Penta dealer who has looked at the installation and everything is as per the operating instructions. the fault is intermittent. The lights seem to flash at random and none can work out what is wrong. Can you help?

Is the bow thruster a 12 volt unit?

Yes the truster is a QL CT900. The controller part no is 21320007. Why?

The reason that we ask is that there appears to be a slight topic with the Instructions when installing these units. The CT900 details a Required Minimum Battery Capacity of 1050 CCA or 150Ah/12 V. We have experienced this and if you look at the requirements table in the instructions the 12V models of the BP800 & SP600, SP900 models show a higher CCA requirement than for the 24 volt models. In contrast the CT600 and CT900 models show the same battery requirement for both 12 and 24 volt.
We have encountered this problem and increasing the battery size on the 12 volt models above 1700 CCA fixes the problem. However, you will need to speak to your local Volvo dealer about this if the unit is in warranty, as this is yet to be proven through Volvo Penta. We have mentioned it, but undertsand that Volvo are conducting their own tests on this. You'll need to be careful if you don't want to be stuck with a bill for the batteries.