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Joshua Scholar

Broken radiant sensors and leaking gas

5 posts in this topic

I've had two customers in the last week say that their dryer wasn't heating but that they smelled gas when it was on.


In neither case was the gas line leaking.


Since I've never heard of a dryer leaking gas when it was on, I told the first customer that I recommended replacing the dryer but that if he wanted to risk a repair I'd replace the radiant sensor and the coils...


He wasn't worried about gas but he thought that the cost of a repair was too much so he didn't get one, nor did he pay me :/


In the second case the customer said that it was cold ONCE and smelled of gas.  I took off the radiant sensor and saw that that the glass was broken in two.   I suspect that if the sensor triggered when the ignitor wasn't hot yet, then it could leak gas.  In their case I did the repair.


So this isn't a question, it's just an observation.  The radiant sensor is a part that's supposed to make the machine safe and prevent it from starting the gas when before the ignitor is hot, and apparently they can fail in a way that makes dryers dangerous.


Josh Scholar

Edited by Joshua Scholar

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This doesn't answer your question but it does explain what the sensor does, and how to check it.


Can one partially fail?

Good question.

Maybe 1 of the more seasoned pros will weigh in shortly;


Open Radiant Sensor

The radiant sensor is designed to detect the heat from either the ignitor or the burner flame. It is basically a bimetallic switch or thermostat. Its primary failure mode is to char and burn away the switch contacts rendering it unable to close and carry current. The radiant sensor is probably the least likely component in the burner assembly to fail.


Tools Required

  • An ohmmeter set for the lowest ohms scale.
Procedures for Gathering Confirming Data
  1. Open the dryer bottom access panel or open the burner access door. Start the dryer in a cycle that demands heat.
  2. When the radiant sensor stays open at any temperature, the ignitor is in series with the secondary coil and won't draw enough current to glow. The cool ignitor will be lower in impedance than the booster coil so current will be shunted away from the booster coil. The net result: the primary valve won't open, the igniter won't glow and there will be no flame. It's time to check the radiant sensor.
  3. Turn the dryer off and disconnect the dryer power cord. Remove the front of the dryer if you don't have full access to the burner assembly.
  4. Disconnect the two wires leading to the radiant sensor on the burner funnel.
  5. Place the probes of the ohmmeter on the two terminals of the radiant sensor. If the meter doesn't move, the sensor is bad. Touch the two probes to each other to verify that the ohmmeter is working. Remove the failed sensor from the side of the funnel. If the meter reads 0 ohms, the sensor is OK and you need to check the operating thermostats.
Parts Required

Use the appliance model number to order the correct replacement radiant sensor.

Procedures for Replacing the radiant sensor
  1. Reattach the new sensor to the side of the burner funnel.
  2. Reconnect the two wires to the radiant sensor.
  3. If you had to remove the whole front of the dryer, replace it now.
  4. Plug in the dryer.
  5. Turn the timer to a cycle that demands heat and start the dryer.
  6. Verify that the ignitor glows, the gas valves open and the flame starts.
  7. Replace the access panel or close the viewing port.



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...  I took off the radiant sensor and saw that that the glass was broken in two. 

glass ?

what Dryer model is this ?


If the Radiant Sensor was stuck "closed", the Ignitor would stay ON

and the Gas Valve wouldn't "open"


If the Radiant Sensor was stuck "open" the Ignitor wouldn't glow and the Gas Valve wouldn't "open"

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Radiant sensor has a window facing the flame.





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Yeah it was that window that was broken.


It was a normal, old stackable Frigidaire dryer.

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