Frymaster E27

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.

Diagnostic steps

1. 01

   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.

2. 02

   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.

3. 03

   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.

4. 04

   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.

5. 05

   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.