NTC Temperature probe/sensor

[JJR]

Hi Guys, I'm sure most of you know the answers to my question, so please help if you can.

I've got a washer/dryer that doesn't dry, it has 2 thermostats both of which have continuity, it also has 2 NTC temperature probes/sensors (thermisters?) neither of which have continuity. I think the NTC's are faulty, am I right or wrong?

Also 1 of the NTC's connector plugs has both wires snapped off, does polarity matter here?

NTC = Negative Temperature Coefficient, so resistance decreases as temp rises, so room temp should have higher resistance I think?

Hope you can help.

Dave

[senz_90]

Re: NTC Temperature probe/sensor

If open, that is more likely failed. From i test and learn it should show reading on resistance, it is about 4 to 5 ohms. no polarity. maybe the others know better. correct me if im wrong.

[SeanB]

Re: NTC Temperature probe/sensor

NTC thermistors typically have a resistance of 10k or so at room temperature. They are not polarity sensitive, and if you have ones that are little copper blocks with 2 black leads coming out thet are pretty common spare parts. You are right in the temperature and resistance reading.

[JJR]

Re: NTC Temperature probe/sensor

Thanks guys, just as I thought.

I will pick up the parts on Monday.

Looking forwards to dry clothes, it's a bit chilly here

[JJR]

Re: NTC Temperature probe/sensor

Ok. I have a fully working washer/drier again

The temperature probes that I thought were faulty actually work perfectly, I had tested them with cheap 830 multimeter I keep at home, I tested them again at work today with my Amprobe meter and they were fine.

The problem was just failed wire connection to one of the probes

The moral of the story is don't rely on cheap & nasty meters.

[senz_90]

Re: NTC Temperature probe/sensor

Ok. I have a fully working washer/drier again

The temperature probes that I thought were faulty actually work perfectly, I had tested them with cheap 830 multimeter I keep at home, I tested them again at work today with my Amprobe meter and they were fine.

The problem was just failed wire connection to one of the probes

The moral of the story is don't rely on cheap & nasty meters.

that 830 meter about $3.5 on my town. btw what resistance reading that you got on NTC?

you forget one thing about moral of the story. always keep the eyes for loose connection or solder joints

[JJR]

Re: NTC Temperature probe/sensor

Ha, yeah the 830 meter I've had for 3/4 years now, bought 2 for £5.00, 1 blew last year. It usually only gets used for checking voltage on laptop charges, I use the Amprobe for everything else.

As for the loose connection, my only excuse is my stupidness

[JJR]

Re: NTC Temperature probe/sensor

Forgot to say, the resistance on the NTC probes at room temp was 7Kohms on both.

[senz_90]

Re: NTC Temperature probe/sensor

thanks. im curious about standard ohm values for that components. it looks like the standard value about 10k like seanb advice.

[JJR]

Re: NTC Temperature probe/sensor

Hi, one sensor was 6.7k the other 7.1k, the room temp was a cool 15c at the time and as I warmed the sensors in my hand the resistance dropped, so to get a reading of 10k it would have to be very cold indeed.

Of course different sensors will have different values.

These are to parts we are talking about.
http://www.ransomspares.co.uk/parts/...-ntc/79397.htm

http://www.ransomspares.co.uk/parts/...-ntc/79396.htm

[senz_90]

Re: NTC Temperature probe/sensor

Hi, one sensor was 6.7k the other 7.1k, the room temp was a cool 15c at the time and as I warmed the sensors in my hand the resistance dropped, so to get a reading of 10k it would have to be very cold indeed.

Of course different sensors will have different values.
,
These are to parts we are talking about.
http://www.ransomspares.co.uk/parts/...-ntc/79397.htm

http://www.ransomspares.co.uk/parts/...-ntc/79396.htm

it will different here as room temp about 31 degree celcius here. nevermind about standard values. i forgot that we are in the different partof world. lol