How many ohms should a thermistor be?
Before any heat is applied to the thermistor, its resistance value should be very closely near its rated resistance value. So, for example, if we are testing a 10KΩ thermistor, before we apply any heat, its resistance value should be very close to 10KΩ. If you’re in a relatively warm room, it may be about 9.3KΩ.
How do you test a thermistor with a multimeter?
Since thermistors are designed to be temperature sensitive, testing them involves the application of heat. Set the multimeter to resistance mode. Hook up the terminals of the multimeter to leads on the thermistor. It does not matter which lead goes to the terminals, as polarity is not important in this test.
How do you find the resistance of a thermistor?
NTC (%/°C) × Temperature Tolerance (± °C) = ± % Resistance Tolerance. For example, to determine the resistance tolerance of a Curve 44 thermistor with a ± 0.2 ̊C tolerance at 100 ̊C, -2.93% / ̊C [NTC @ 100C] × (±0.2) [Temperature Tolerance] = ± 0.586 % Resistance Tolerance.
Do boiler thermistors fail?
If your boiler thermistor provides very unpredictable readings with sharp rises and falls, it might be faulty. Similarly, if the resistance reading does not change smoothly and proportionately to the change in temperature, it might be defective.
Should thermistor have continuity?
The thermistor that you are asking about is a negative temperature coefficient sensor. It should always measure continuity. The resistance of this sensor is used by the control board to determine temperature.
How do I know if my thermistor is bad?
The most common way to know if a thermistor is bad if it starts displaying inaccurate temperature readings. This can be caused by excessive heat, improper handling, a thermal mismatch, or a dip in resistance accuracy due to regular use and age.
How does the resistance of a thermistor change with temperature?
When temperature increases, the resistance increases, and when temperature decreases, resistance decreases. This type of thermistor is generally used as a fuse.