Troubleshooting the E-20 S Safety Relay Failure Error Code

Overview

The E-20 S – Safety Relay Failure error occurs when the GMU (Gas Management Unit) internal safety relay K1 does not produce the expected output signal. The K1 relay must energize as part of the safety interlock chain before ignition can begin.

When K1 fails to energize or the expected output is not detected, the ignition sequence stops and the equipment will not proceed to ignition.

Possible causes:

• Failed GMU internal safety relay (K1)

• Open, damaged, or disconnected wiring between the GMU K1 output and the downstream safety circuit

• Loose electrical connections in the safety interlock circuit

• Display control is not responding

Call Avoidance Steps

Before dispatching a service technician, perform the following checks remotely or have the customer perform them if qualified:

1. Cycle fryer power OFF for 30 seconds and then power ON.

2. If the error returns immediately, schedule a service visit for electrical troubleshooting.

Field Troubleshooting

Recommended Parts

• GMU (Gas Management Unit) Board

• Display Control Board

Recommended Tools

• Digital Multimeter

• Basic Hand Tools (screwdrivers, nut drivers, etc.)

Troubleshooting Steps

1. Inspect wiring from the GMU K1 output to the downstream safety circuit.

• Check for loose connections, damaged conductors, corrosion, pinched wires, or disconnected terminals.

• If damage is found, repair or replace the wiring and test the unit.

• If wiring is intact, go to Step 2.

2. Inspect GMU Ignition sequence Lights

• Initiate a call for ignition.

• Review lights of Ignition sequence on GMU Board.

• If lights are getting all the way to the Heat Valve light and it's not turning on, go to Step 3.

• If lights are not going past the SFTY 24V, go to Step 4.

3. Test Main Valve Heat - Service Mode

• Access the Service Menu on the Control

• Turn on and test each Ignition sequence.

• If the main burn turns on in service mode, GMU is good and proceed to step 5.

• If the main burn still does not turn on in service mode, replace GMU Board.

4. GMU K1 Voltage output check

• Check for 24 VAC.

  • If no voltage, replace GMU.

  • If voltage present, check wiring and replace wiring if damaged.

5. Display Control Reset

• Using the control reset (black) switch under the fryer press and hold until the display control resets.

  • Retest ignition sequence. If error clears and unit starts operating, have customer monitor it for further issues. If error returns after, replace Display Control.