IPSO Washer-Extractor Error Code E oP: Temperature Sensor Open
E oP on an IPSO CHM495R washer-extractor means the control sees the temperature sensor circuit as open, with a reading below 0 F. That value cannot be real, so the sensor, its connector or its wire is broken or disconnected. Check the actual wash temperature and call us to test the sensor.
Medium: the machine runs, but heated washes lose temperature control.
- Code
- E oP
- Maker
- IPSO
- Equipment
- Industrial laundry
- Applies to
- CHM495R family washer-extractor front-end control (20-100 lb)
What does IPSO error code E oP mean?
The control reads water temperature through a sensor whose resistance changes with heat. It knows the range that makes sense for a washer. If the circuit is open, the reading falls to an impossible value, below 0 F, and the control posts E oP instead of using it. A heated machine then loses temperature control, because the control can no longer tell whether the water is hot enough. Plant supervisors see washes that run cooler than the formula calls for. Because thermal programs depend on accurate readings, the problem should not be left for long. The open circuit can sit at the sensor itself, in the wire to it, at a connector, or in the sensor input on the control. This code is the opposite of E SH, which reports a short instead of an open.
Affected models and control systems
CHM495R washer-extractors, 20 to 100 lb, with the front-end control. Other controller generations use different codes.
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
- E oP on the display
- Wash temperature lower than the formula target
- Heater seems not to run, or runs too long
- Cycle may continue without temperature control
Possible causes
Listed in IPSO's documentation
- Temperature sensor circuit open, reading below 0 F
Other likely causes — what usually sits behind error code E oP on this control. A technician confirms which one it is before any part is replaced.
- A temperature sensor that has failed open behind E oP
- A wire between the sensor and control that is broken
- A connector at the sensor that has come loose or corroded
- A sensor input on the control that reads open
Safe checks before calling for service
- Compare the actual wash temperature with the formula's target.
- Stay away from the sensor and its wiring.
- Let the batch finish if the cycle carries on, and note that it missed temperature.
- Call us to test the sensor, and tell us how far the wash temperature fell short.
How a technician diagnoses error code E oP
- Read the code and confirm E oP is steady, not intermittent.
- Check the sensor connector for looseness or corrosion with power locked out.
- Measure the sensor resistance and compare it with a reference temperature.
- Test the wire run for a break.
- Check the control input, and replace the sensor or harness only on a failed test.
- Sensor wires run through the cabinet near live 208-240 V parts and moving parts. Reading sensor resistance correctly requires a meter and reference values. A broken wire can look like a bad sensor, so the wrong part gets replaced.
How error code E oP differs from similar codes
E oP is an open circuit (below 0 F). E SH is a shorted circuit (above 212 F). E Ht is a heater that never reached the target.
Technical reference
- Document
- Washer-Extractor Programming CHM495R_SVG, Part No. F8208501ENR10, March 2017, Error Codes (pp. 36-37)
- Edition
- Part No. F8208501ENR10, March 2017
- Models / control
- CHM495R family washer-extractor front-end control (20-100 lb)
- Section
- Error Codes table, pp. 36-37 (E Pr only on Design 1 models; Ed01-Ed11 on Design 2 and 3 models)
- 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 IPSO industrial laundry error codes
Is the linen safe to use after an E oP wash?
It was washed, but maybe not at the formula temperature. A supervisor should decide on a rewash.
Can I clear E oP by restarting?
It may reappear immediately, since an open sensor circuit does not heal itself.
Does E oP mean the heater has failed?
No. The control just cannot read the temperature.
Need help with IPSO error code E oP?
A technician confirms the cause on site and gives you the price in writing before any work starts.