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NTC sensor:

NTC thermistor is a type of resistor whose resistance varies significantly with temperature.  The resistance of NTC thermistor decreases with increasing temperature. Therefore, this device is called a negative temperature coefficient (NTC) thermistor.  NTC thermistors are widely used as temperature sensors.  Self-resetting over current protectors and self regulating heating elements.  The first order temperature coefficient of resistance (K) of sensor that we are selling is 10K.

Appearance of NTC sensor's shape:

The common shape of NTC sensor for temperature controller.

The special shape of sensor for only D-1500 controller

How to replace (change) sensor

For common shape of NTC sensor

When sensor is out of work. It must be replaced to detect the right temperature.  Most of water temperature controller's NTC sensor cable for aquarium purpose has been connected to the main PCB board with soldering condition.  It makes us very hard to replace it.  The simple way to replace it without opening the main temperature controller case and soldering are as follows:

Step 1:  cut the sensor cable at the point about 3-4" away from the controller case.   

Step 2: After cutting it, peel off an insulated part of the old and new sensor cable about 1/2" until a bared electric cable is appeared.

Step 3: Then connect the end of a bared electric cable to the connector - connector can be used with European-style terminal strip.

Step 4: Fasten the screw firmly.


For special shape of sensor for PH D-1500 controller

This is a plug-in type, very easy and simple way to replace it.

Step 1: Pull out the old sensor cable

Step 2: connect the new sensor cable


The trouble shooting chart

*** This is a general rule-of- thumb for replacing sensor



Heating mode indicator light works.  But heating tube does not emit heat

Replace Sensor or replace heating tube

Display temperature on the controller shows a very high temperature

Replace Sensor

Heating mode indicator light is blinking very frequently and heating tube does not emit heat

Replace Sensor

Heating tube emit heat continuously beyond setting temperature

Replace Sensor

Heating mode indicator light does not work

Replace Sensor


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