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Best thermistor for interior temperature?

Umitbat

New Member
For a car hvac system.
The problem is sensor is not saperate it is in the dash assy inside little vents.
The probe of sensor is gone so i need to put smt.
What value should i try?20200110_122307.jpg
 

Wp100

Well-Known Member
Probably it uses a bead type, but the value could be anything, you need to find its value from the workshop manual for you car .
Try enquring in the car makers users forum for such info.

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Wp100

Well-Known Member
There are a wide range of thermistor values, which are produced when at 25 deg C.

As you can see my cars thermistor is probably a 2k2 one , but yours could be different, so you might have to try several thermistor values to find the right one, though you might find using a 50k multiturn pot a quicker way to find the right value for the themistor...

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Umitbat

New Member
After measurments actual cabin temp is 2 degrees lower then set temp.
It is stable at all degrees like 22 is 20 and 26 is 24 in cabin.
 

Wp100

Well-Known Member
Maybe i will try with a 10% more value to see if it will be better.
Personally would not bother as: -
1. many thermometers, even digital ones can be +-1c out, just compare several together.
2. depends where in the cabin / air vent you measure the temp ?

Do not forget the NTC means Negative, so the higher the temp the lower its resistance.

If the next value NTC gives a swing too high the other way, you could try adding a 1k trimmer pot in series with the NTC, which might allow you to balance it better, but seems a lot of messy work for such a small difference.
 

Umitbat

New Member
Personally would not bother as: -
1. many thermometers, even digital ones can be +-1c out, just compare several together.
2. depends where in the cabin / air vent you measure the temp ?

Do not forget the NTC means Negative, so the higher the temp the lower its resistance.

If the next value NTC gives a swing too high the other way, you could try adding a 1k trimmer pot in series with the NTC, which might allow you to balance it better, but seems a lot of messy work for such a small difference.
You are right. It works fine. One side of me was actually just like your thoughts and the other was go play some more. I think this is ok. Thanks for nice answer.
 

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