Frymaster E27 Error Code
Heating failure - pressure switch. The air pressure switch has failed closed. Call service.
Source: Frymaster FQ4000/M4000 Service Manual (819-7955)
What does Frymaster E27 mean?
The air pressure switch is a normally-open safety device that should only close when the combustion blower is running and producing sufficient airflow. E27 means the controller detected the pressure switch already closed before the blower was commanded on — indicating the switch has failed in the closed (shorted) position. This is a wiring safety fault: the controller refuses to proceed with ignition because the interlock that proves airflow is bypassed.
Symptoms
- Display shows E27 immediately at startup or when heat is commanded, before the blower runs.
- Fryer will not attempt ignition; heating is locked out.
- Error may appear consistently at every power-up if the switch is permanently shorted.
- No unusual sounds — the fault is detected before the blower starts.
Common causes
- Failed air pressure switch with contacts welded or stuck in the closed position.
- Wiring short circuit — the switch signal wires have shorted together in the harness or at a connector.
- Moisture or oil infiltration into the pressure switch body causing internal shorting.
- Incorrect replacement switch installed with normally-closed contacts instead of normally-open.
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Diagnostic steps
Power down and isolate the pressure switch
Switch the fryer off and open the circuit breaker. Locate the air pressure switch in the burner compartment and disconnect its wiring harness connector.
Test switch state at rest
With the switch disconnected and the blower not running, measure continuity across the switch terminals. A normally-open switch must show no continuity (open circuit) at rest. Continuity at rest confirms the switch has failed closed — replace it.
Inspect the wiring harness for shorts
Even with a good switch, measure resistance between the two switch signal wires at the SIB board connector with the switch disconnected. Any low-resistance reading (below 1 MΩ) indicates a wiring harness short that must be repaired before installing a new switch.
Verify replacement switch type
Confirm the replacement switch is rated as normally open (N/O). Installing a normally-closed switch will replicate E27 on the new part. Cross-reference the Frymaster part number on the original switch to ensure an exact match.
Restore and test
Reconnect the wiring harness, restore power, and command a heat cycle. The controller should energize the blower, wait for the switch to close, then proceed to ignition. Confirm E27 does not reappear.
When to call a professional
E27 requires a licensed technician if the wiring harness shows evidence of moisture ingress or oil saturation, or if the root cause cannot be isolated to the switch alone. Any modification to the combustion interlock circuit must be restored to OEM specification — bypassing a pressure switch interlock creates a risk of unventilated gas ignition. 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. 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.
Drain valve not open. The drain valve was commanded open but confirmation is missing; filtration and top-off disabled. Call service.
Sources: www.manualslib.com
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