• Condition:  Dryer Master has detected the burner temperature has reached a high or low value level reaching the “warning” status.
  • Alarm Action Taken: WARNING ONLY
  • Component: RTD (Resistance Temperature Detector), Modulating motor & “Butterfly” valve
  • Location: The RTD originates in the junction box up inside the dryer inside of the square ductwork mounted just inside the lower access door under the burner.  The sensor runs outside the airduct into the heating chamber and is then ran vertically usually along side of the internal access ladder in the heating chamber.

The modulating motor and butterfly valve are located on the fuel trane at the bottom of the dryer.

Tools Required for Service:

  • Voltage/continuity meter (to check ohms & voltage)
  • Small Phillips screwdriver (to loosen screws on mod motor lid)
  • Wire strippers (if replacing sensor or refreshing connection)
  • Replacement small wire nuts or crimp connectors
  • 3/8” wrench or impact w/3/8” socket (to loosen p-clips if replacing RTD)

Tech tip: (Value is set in the “Dryer Master Alarm Settings” screen)

 (RTD 1000 ohms @70 degrees device) (Modulating motor 115 vac input w/24 vac internal transformer)

The RTD used for this function is an “averaging” unit.  It senses temperature along the entire length of the unit and sends back the “average” temperature readings/resistance to the controller.

(Warning High Plenum Temperature is an alert indicating that the Plenum Temperature is approaching a critical level and should be investigated.)

Potential causes of this alarm condition:

  • Too high of gas pressure from vapor regulator causing too much temperature rise with very little modulating adjustment from the motorized gas “butterfly” valve
  • “Butterfly” valve stuck open or faulty
  • Faulty modulating motor
  • Open circuit on RTD reading 350 degrees
  • Corroded/loose connection on RTD
  • Faulty RTD
  • Warning High Alarm setpoint too low
  • Warning Low Alarm setpoint too high