Frymaster E70 Error Code
OQS temp high. Oil temperature is too high for a valid OQS reading; filter between 300°F (149°C) and 375°F (191°C).
Source: Frymaster FQ4000/M4000 Service Manual (819-7955)
What does Frymaster E70 mean?
The Oil Quality Sensor (OQS) measures Total Polar Materials (TPM) in the oil to determine when oil needs to be changed. The OQS only produces valid readings within a specific oil temperature window. E70 means the oil temperature was above 375°F (191°C) when an OQS reading was attempted — too hot for the sensor to produce a reliable TPM measurement. This is not a fryer fault; it is an indication that filtration was initiated at too high a temperature for OQS sampling.
Symptoms
- Display shows E70 during or after a filtration cycle when OQS sampling was attempted.
- OQS reading is not recorded for this cycle; oil quality assessment is skipped.
- Fryer continues operating normally — this is an OQS measurement condition error, not a heating fault.
- E70 may appear if filtration is initiated immediately from high cooking temperature without a cooldown.
Common causes
- Filtration cycle initiated while oil temperature is above 375°F — most common after high-temperature frying.
- OQS reading requested manually while the fryer is at full cooking temperature.
- Oil temperature setpoint configured above 375°F on a model that includes OQS.
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Diagnostic steps
Allow oil to cool before initiating an OQS filtration
If OQS oil quality assessment is needed, reduce the fryer setpoint or allow the oil to cool naturally to between 300°F (149°C) and 375°F (191°C) before running a filter cycle. The OQS requires this temperature window for accurate TPM measurement.
Run the filtration cycle within the correct temperature range
Initiate the filtration cycle when the oil temperature is confirmed to be between 300°F and 375°F. The OQS will sample the oil as it passes through the sensor during the filtration cycle and produce a valid TPM reading.
No component repair is typically needed
E70 is a condition code, not a hardware failure. If the fryer consistently operates above 375°F and OQS readings are always skipped, review whether the oil temperature setpoint is appropriate for the product being fried.
When to call a professional
E70 does not require a service technician under normal circumstances — it is a condition advisory. Contact a technician only if E70 appears at temperatures that should be within the valid range, which could indicate an OQS sensor fault or a calibration issue with the oil temperature probe. Frymaster service: 1-800-551-8633.
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Other Frymaster Error Codes
Temperature probe failure - RTD out of range
High limit 1 exceeded - vat temp above 410°F
High limit 2 exceeded - high limit switch opened
High limit problem - vat temp above 460°F, disconnect power immediately
Failed temperature probe or controller
Frypot temperature above 410°F
Heating problem / ignition lockout
Heating failure. The heating-control latch circuit failed, or the heat contactor failed to latch.
Heating failure - blower. The air pressure switch(es) failed to close.
Heating failure - pressure switch. The air pressure switch has failed closed. Call service.
Heating failure. The fryer failed to ignite and has locked out the ignition module.
Top-off probe failure. The ATO (auto top-off) RTD reading is out of range. Call service.
Sources: www.manualslib.com
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