My dryer runs and heats up as expected in timed modes. However, in REGULAR mode (or automatic mode), it runs normal too, but the heat stops “heating” after about 5 minutes of being turned on. The Dryer LED indicator still shows it is drying with heat. It hasn’t even entered the cool mode yet. The clothes do not dry completely.
I have replaced the 4″ vent duct with a new clean duct. I cleaned and vacuumed the inside of the dryer too, including internal duct parts. Air blasted the blower blades. I removed the plastic filter housing and pressure washed the insides perfectly clean. Air flow is very plentiful. Looks brand new. Since I do HVAC as a living, I checked the following components: Radiant sensor, Thermostat (gas flame), Thermal fuse, Thermistor and Thermostat (dryer side). I cleaned all of them properly.
My conclusion is, that the thermistor (reading 10K ohms at room temperature) could be bad since I do not know for sure what it is supposed to read at different temperatures and it is a sensor that is directly exposed to the elements inside the dryer. I paid special attention on cleaning it, suspecting that it may have a bi-metal surface in contact with lint and moisture.
My other concern is the two “moisture sensors” (cathodes?). They look clean (and I wiped them down with water and a clean cloth) and I made sure that the blue wires are not loose when re-attaching them. How can two pieces of clean metal go bad? They look like stainless steel. To narrow the problem down, I thought about jumping the two blue wires, by-passing the moisture sensor plates to simulate a constant presence of moisture, but didn’t want to do any possible damage. My second thought was to place a wet sponge securely across the two plates to see if any improvement is noticed during a test run.
Lastly, the unlikely problem could be the electronics within the circuit board.
What do I need to do to positively find out what the problem is so I can fix the dryer?
Your reply is deeply appreciated.
Regards, Patrick Kieran.
- Patrick Kieran asked 7 years ago
Hi. The first thing that we need to make sure of is that on the timed cycles that it is heating the entire cycle. If on either cycle the dryer heats at the beginning of the cycle and then produces no heat for the rest of the cycle you may have bad primary and secondary gas coils. Your thermistor is not faulty if you getting about 10k ohms at room temp. You can also check the moisture sensor by unplugging the dryer and placing a piece of metal ( like a screw driver) across the two metal strips and check for continuity. If you get a reading on your meter your moisture sensor is not bad. If everything above checks out good it looks like you may have and issue in the timer or control board. Once you perform these tests please let me know and we can proceed further.
Technician Brian V.
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Well your are correct “typically” you will never see any type of failure with the moisture sensor bars. I cant say I have ever replaced them on any dryer. The thermistor is basically a cycling thermostat for your heat. I would assume if you had an issue there that you would be having the same type of issues with your timed dry cycle. When the unit stops heating do you see the ignitor glow and then fade away without the burner firing up? If this is the case I would be leaning towards weak gas coils however this should also present itself in timed dry cycles as well. If you wanted to test the moisture sensor you can just put a piece of metal across the two strips and check continuity with your ohm meter. Hope this helps let us know if you have any further questions.
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