If you think your temperature sensor is playing up, a good trick is to unplug both sensors and switch them over, if the faulty sensor reading disappears by plugging in the other sensor then it's most likely are the faulty sensor needs replacing. The controller will also generally inform you of a sensor fault.
The next step is to identify your controller. There are two main solar controller manufacturers in Australia - Ascon and Dontek Electronics. These are the largest so chances are you may have one of these controllers. Both companies re-brand their controllers to the specific solar pool heating company branding they are supplying, however these controllers can be identified by the form factor of the controller, that is by the general shape of the controller and where the buttons are located on the face. Blank templates of both an Ascon MS3D controller and a standard Dontek AquaSun2 or 3 are shown below.
Identifying the Controller - Blank Controller Templates and Sensor Plugs
Shown below are blank form factor boxes for both controller types. Note the branded label on your controller can be any color but generally the elements that are shown on these blank pictures should be present on all controllers.
Ascon Solar Pool Heating Controller & Sensors
The Ascon controller has a quite distinct form factor with a red screen and red light text. Ascon has not changed their temperature sensor for at least 10 years or longer so chances are the Ascon sensors listed below will be compatible with your older Ascon controller.
Dontek Solar Pool Heating Controller & Sensors
The Dontek controller also takes a distinct square form factor with a green screen with black text. If your controller looks like this the thermostats below are probably compatible.
Note: Dontek in 2017 updated their controllers to + versions. These have special temperature sensors marked by a + label, while the + version controller can take any of the older version below listed sensors, it's best to custom order a + sensor for the newer + controller.
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