Speed Queen Commercial Dryer Error Code OP: Open Thermistor Circuit
OP on a Speed Queen single or stacked dryer means the control reads the thermistor as disconnected. The thermistor is the temperature sensor, and without its reading the dryer may stop the cycle. Let it cool, check the lint screen, and call us if OP returns.
High: without a temperature reading the dryer cannot heat safely.
- Code
- OP
- Maker
- Speed Queen
- Equipment
- Dryers
- Applies to
- Single/stacked dryer electronic control (DRY716C family)
What does Speed Queen error code OP mean?
A thermistor is a small sensor whose resistance changes with temperature, and the dryer's control uses it to judge how hot the air is. The control sends a small signal through the thermistor circuit and reads what comes back. If the thermistor is unplugged, the wire to it is broken, or the part itself has opened, no signal returns, and the control reads a physical open circuit. That is what OP means (display text: OP). With no usable reading, the dryer cannot hold heat properly, so it may stop the cycle rather than guess. The code is about the sensor and its wiring only. The manual lists three possibilities: a thermistor unplugged or loose at its connector, a broken wire leading to it, or a control input that reads the thermistor as open. A clogged exhaust is a separate problem that makes drying slow, but it is quick for an owner to rule out. If a gas dryer ever gives off a gas smell, leave and call the gas utility from outdoors.
Affected models and control systems
Speed Queen single and stacked dryers with the electronic control (DRY716C family). The same open-sensor idea appears as E:OP on the colon-style readout.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- OP on the display
- The dryer stops or ends the cycle early
- Laundry is damp because heat was not controlled
Possible causes
Listed in Speed Queen's documentation
- Thermistor unplugged or loose at its connector
- Broken wire leading to the thermistor
- Control input reading the thermistor as open
Other likely causes — what usually sits behind error code OP on this control. A technician confirms which one it is before any part is replaced.
- A connector jarred loose after the dryer was pulled out for cleaning behind it
- A wire fatigued where it flexes near the heating area
Safe checks before calling for service
- Let the dryer cool with the door closed.
- Confirm the lint screen is clean and the exhaust is not visibly crushed.
- At any hint of gas, step outside and call the gas utility from there.
- If OP returns, contact us and do not open panels; note the cycle and time it stopped.
How a technician diagnoses error code OP
- Read OP and check whether it appears before heat is called for.
- Inspect the thermistor connector and wire for looseness or breaks.
- Measure thermistor resistance and compare it with the specification.
- Check harness continuity back to the control.
- Replace the thermistor or harness once the test points to it, and check the control input last.
- The thermistor sits in the heated air path, so the machine must be opened and made safe before testing.
- A resistance reading means little without the right specification for the part.
- Gas models need someone comfortable working near gas heating parts.
How error code OP differs from similar codes
SH is the matching code for a shorted thermistor; OP is the open one.
Technical reference
- Document
- Single and Stacked Dryers Troubleshooting DRY716C, Part No. 513447, April 2010, Error Codes (p.29)
- Edition
- Part No. 513447, April 2010
- Models / control
- Single/stacked dryer electronic control (DRY716C family)
- Section
- Error Codes (p.29)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Speed Queen dryer error codes
Can the dryer run with OP showing?
It should not. The control has no temperature reading and may stop the cycle.
Is the thermistor the same as the temperature sensor?
Yes, on this dryer the thermistor is the temperature sensor.
Could a tripped breaker cause OP?
No. A power loss shows nothing; OP comes from a thermistor circuit that reads open.
Need help with Speed Queen error code OP?
A technician confirms the cause on site and gives you the price in writing before any work starts.