Electric Dryer, heat cuts off after 1-2 minutes

Dryer Repair
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1

This sympton occurred once before, 20 months ago, I successfully repaired by replacing the control thermistor, WE4M275, after trial and error on all the control devices, thermostats etc. With the latest event, I pulled the suspect part and tested it on my analog multi-meter. It registered 100K ohms at room temp and 80K ohms at 87 deg F. It seems like the part is within spec, is it? Also tried a continuity check with the meter set to the ground symbol, I did not get the audio tone, but the meter read 100K ohms. Not sure if or how thermistors should respond to a continuity check. What do I do next? Thanks!

3

Hi Bob,

There are two control thermistors, inlet and outlet (#506 at the [Replacement parts for General Electric DPSB620EC4WW Electric dryer | AppliancePartsPros.com](http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5233374&diagram_id=29416019"]diagramdiagram[/URL] & #240 at the ). You did check only one of them. So you may want to check the second one as well.

Here are the breakdown diagrams and [URL="http://www.appliancepartspros.com/partsearch/model.aspx?model_id=5233374)

Gene.

4

Thanks Gene, as you recommended I did a check on the inlet thermistor and got a reading of 7900 Ohms. I did the check with both leads on because I coudn’t get a lead off without pulling the drum, which I didn’t want to do tonight if I didn’t need to. Made the measurement several times with the probes near the base of the prongs and the readings were consistent. Have no idea what the R should be, is 7,900 at room temperature in spec? Do I need to heat it and check a range of resistance at different temps? I have an infrared thermometer, so its doable, probably have to pull the drum though.

Also checked the continuity of both the outlet back-up thermostat and the high limit safety thermostat with one lead off and both were OK.

Thanks again for your help.

Bob

5

— Begin quote from BobFixx;736123

…I did a check on the inlet thermistor and got a reading of 7900 Ohms. I did the check with both leads on…

— End quote

Such result is inaccurate and we can not trust it. At least one lead has to be removed.

I believe the readings for both thermistors should be about the same at the same temperature.

Gene.

6

Gene - I pulled the drum to get good access, took both leads off and checked the Thermistor Control Inlet (WE4M298) with the following readings:

100K Ohms at 74 deg F (same as WE4M275, outlet Thermistor)
45K Ohms at 87 deg F (WE4M275 was 80K)
32K Ohms at 94 deg F (WE4M275 was 65K at 92 deg F)
25K Ohms at 100 deg F (WE4M275 was 60K)

Also checked continuity on the Safety Thermostat (Thermal Fuse) and it was OK.

Had no luck with GE or any on-line reference material to determine what the specs should be for these devices. Hoping a pro like you would know. I would think the inlet Thermistor would be exposed to higher temps since it is so close to the coils and inside the shroud. If so, I’m guessing its sending an early signal to shut off the heat. Can you help?

Thanks,

Bob

7

Hi Bob,

According to the tech sheet (attached to the post) the values for both thermistors suppose to be the same. So, [part]WE4M298[/part]

is out of the range.

Gene.