Sea water temperature st-60

[Fred7825]

My st-60 read out says 188 degrees. Can this be reset to the correct temperature?

 

[Sailgunner]

You can try to recalibrate it. Do you have the instructions?

 

[Rich Stidger]

Sounds like the sensor is kaput to me.

 

[Bill Roosa]

sounds like corrosion in the sensor wires. The sensor is just a thermistor. Fancy word for a resistor that changes its resistance in a predictable way as it changes temperature. Higher temps have higher resistance and lower temps lower resistance.
Soooo if you have a high resistance corroded connection in the sensor wire........ the sensor head can't tell the difference between that and the thermistor being at a high temp.

 

[Rich Stidger]

Higher temps have higher resistance and lower temps lower resistance.
Soooo if you have a high resistance corroded connection in the sensor wire........ the sensor head can't tell the difference between that and the thermistor being at a high temp.

Gee, every thermistor I've ever worked with has a negative coefficient where the resistance goes down as the temperature rises. However, I do see that there are positive coefficient devices.

However, the ST-50 and I presume the ST-60 has a negative coefficient device. The lower the temperature, the higher the resistance.

I too have a problem with my ST-50 temp display, but mine displays dashes. I downloaded the attached document from Raymarine quite a while ago. It could help you in troubleshooting to find out if it is the sensor or the display head.

 

[Stu Jackson]

Gee, every thermistor I've ever worked with...

Didn't they get paid overtime? :dance:

 

[artboas]

I know what your problem is

Gee, every thermistor I've ever worked with has a negative coefficient where the resistance goes down as the temperature rises. However, I do see that there are positive coefficient devices.

However, the ST-50 and I presume the ST-60 has a negative coefficient device. The lower the temperature, the higher the resistance.

I too have a problem with my ST-50 temp display, but mine displays dashes. I downloaded the attached document from Raymarine quite a while ago. It could help you in troubleshooting to find out if it is the sensor or the display head.

You have replaced your head, and not the transducer.
The original transducers had no temp output.
I believe it's the brown wire.

 

[pabraam]

Talked to one of the Raymarine rep's at the Amsterdam Boat Show (HISWA) yesterday and basically, as they admitted frankly, this [sea]water temp. feature has been a PITN (OK PITA) from the beginning, also on the ST-70, and they are unable to do anything about it.
So, disregard the readings....

 

[Lyle]

I have owned 5 boats with Autohelm/Raymarine ST50 and ST60 instruments and all of them had inaccurate sea temp readings. I agree - it is a poorly designed feature.