Speed Queen Dryer tH: Thermistor Open or Shorted — Temperature Sensor Failure
tH on a Speed Queen dryer means the outlet temperature thermistor returned a reading outside the measurable range — either open circuit (infinite resistance, broken sensor) or short circuit (near-zero resistance, shorted sensor). The control board cannot monitor exhaust temperature without this sensor.
The Outlet Thermistor's Role
The outlet thermistor monitors the temperature of air leaving the dryer drum before it enters the exhaust vent. The Quantum Touch control uses this data for:
- Cycle management: Determining when clothes are dry based on dropping exhaust temperature
- Airflow monitoring: Calculating temperature differential for AF (airflow restriction) detection
- Safety: Detecting over-temperature conditions for HL (heater lockout)
With tH active, the board loses all of these functions. The dryer may run on a fixed timer mode or refuse to operate entirely.
Do You Have the Right Tools?
Gas leak detector ($130), thermal fuse tester ($95), belt tension gauge, and vent inspection camera ($180). Our technician arrives with $15K+ in professional tools — your diagnostic is free.
Licensed & Insured · 90-Day Warranty · Same-Day Service
Testing the Thermistor
- Unplug the dryer
- Access the thermistor — typically mounted in the exhaust housing at the rear of the drum
- Disconnect the 2-pin connector
- Measure resistance:
- At room temperature (77F): expect 10-12k ohms for Speed Queen's standard NTC thermistor
- OL (infinity): open circuit — sensor element broken
- Below 500 ohms: shorted sensor
- Within expected range: wiring fault between sensor and board
Speed Queen's Commercial-Grade Sensor
Speed Queen uses a thermistor rated for commercial dryer environments — higher temperature range and longer cycle life than consumer equivalents. The sensor is exposed to exhaust air that can reach 200-225F during high-heat cycles. Consumer thermistors may not withstand this environment long-term.
Same-Day Appliance Repair
Fixed or It's Free
$89 → $0 Service Call & Diagnosis — offer ends May 25
Safety First — Know the Risks
Gas dryers carry carbon monoxide and explosion risk. Even electric dryers involve 240V circuits that can deliver a fatal shock. Our techs are licensed and insured — let them handle the risk.
Licensed & Insured · 90-Day Warranty · Same-Day Service
Replacement
- Unplug dryer
- Remove the rear panel or exhaust housing cover
- Disconnect the thermistor's 2-pin connector
- Remove the mounting screw or clip holding the thermistor to the exhaust housing
- Install new thermistor (Speed Queen 510702P or model-specific)
- Reconnect and reassemble
- Run a timed dry cycle to verify — tH clears when the board reads a valid resistance
Parts and Pricing
| Part | Speed Queen Number | Cost |
|---|---|---|
| Outlet thermistor | 510702P or model-specific | $15-$25 |
| Thermistor wiring harness | Varies | $15-$25 |
Professional repair: $125-$275. Quick repair — 15-25 minutes.
tH sensor failure on your Speed Queen? We carry thermistors for all Speed Queen models. Sacramento area. Book service.
