[CA] [CA11] Axiom/Pro seawater temp source.

[ranmar850]

I am running an Axiom 9 pro and Axiom 7 networked with an EV-100. Running a B175m into the 9 pro and the RV-100 into the Axiom 7. Dashboard app is communicating with the Mercury 150, (4 stroke, 2018 model) giving me most engine parameters displayed. Network appears to be fine, everything is talking, all shared functions working. But the seawater temp is obviously wrong , appearing to more closely reflect OAT than water temp. Going into the transducer page on the Fishfinder app gives me the screen below. As you can see, it tells me this transducer s not the source. Go into the other transducer, and get the same message. I can disable the temp on both transducers, and the indicated temp remains the same, so it is obviously getting its temp from elsewhere-my guess is that it is the OAT sender associated with the Mercury gateway. in the data sources section of the menu, seawater temp is not mentioned.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum ranmar850,

Please click here to view a FAQ addressing Water Temperature sensor prioritization within MFDs running LightHouse II or LightHouse 3 software. Should you switch OFF temperature sensing from the fishfinder sounder settings and Water Temp continue to be populated, then the data item would indeed appear to be originating from the engine system. One may absolutely be able to verify whether this was the case by simply disconnecting the engine gateway from the marine electronics backbone and then switching the marine electronics ON. Should the Water Temp data item remain dashed (while the setting had been configured OFF within the Fishfinder Settings), then it would appear that the engine system is pushing water temperature to the marine electronics. In the case of the latter, it would be recommended that the sensor be disconnected from the engine system, as you have indicated that it is grossly in error.

[ranmar850]

Thanks for that. I found a labelled temp sensor hanging from the loom under the engine controls, so simply unplugged it. As the boat is not in the water, the OAT and transducer temps would obviously be much the same, but I have lost the message saying that this is not the temp source when looking at the B-175M, whereas the RV 100 still has that message , so I could assume I now have the B175M as water temp source. I intend to confirm this by checking temp then gently applying a heat gun from a distance to see if the temp goes up a bit.

[Chuck - Raymarine - Moderator]

ranmar850

Q. So I could assume I now have the B175M as water temp source?
A. Yes. Per the previously referenced FAQ, CP570/CP470 w/1kW CHIRP transducer and Axiom Pro RVX 1kW CHIRP w/1kW CHIRP transducer is prioritized over Axiom Pro w/ Raymarine transducer (i.e. RV100).

[ranmar850]

I still have this problem, and have not been able to resolve it--to briefly recap, the network refuses to use either transducer for a seawater temp source with the engine ignition on. It will read from the B175M, or RV-100, with the ignition off. Once ignition is on, message comes up in the Transducer settings that "this is not the preferred source"
I've done all I can, tried every combination of options available in the network settings. It appeared that the actual temp reading was orinally coming from the Airmar ST-63 paddlewheel/temp sender that comes included with the Mercury motor package. This had not been installed, and was sitting loose in the outboard well, hence reading OAT rather than water. So I disconnected it, trying to get the transducer to read preferred. This then gave me a temp reading of minus 34.7 deg C. with the ignition on. So I reinstalled it, this time removing the paddlewheel and mounting the sender on top of a trim tab. Now it reads 0 deg C with the ignition on.
I have tried disconnecting both the Air Temp and paddlewheel sensors, and the result is still the same.
It would be much easier if there was an option to select Temp amongst the data sources, but there is none. In the FAQ's, it states the Seatalk ng is top priority for water temp--this is also how the Motor communicates with the network, so it would appear I have run out of options, short of turning off my ignition, or going into the transducer settings menu, to get a seawater temp reading?
Again, it would be much easier if the option of manually selecting a Temp source was available.

[Chuck - Raymarine - Moderator]

ranmar850,

With the speed/temp transducer disconnected from the engine system, it would not be expected that it should transmit NMEA 2000 PGNs including water temperature. You may want to check with Mercury Marine to determine whether a setting may be configured on the engine side to eliminate transmission of PGNs including water temperature data (or any data for that matter) when an associated sensor has not been interfaced to the engine system. While a feature request has been submitted to consider supporting source selection for water temperature, Raymarine has not yet identified if/when this feature will be included within a LigthHouse 3 software update.