Troubleshooting an E-21 Error Recovery Fault

Overview

The E-21 error occurs when the PMU/GMU PCB detects from the temp probe that the heat recovery rate from 250°F-300°F or 139°C- 167°C has taken longer than 1 minute 40 seconds.

Field Troubleshooting

1. Remove the rear panel of the fryer to gain access to the contactors and elements.

2. Inspect all electrical connection points at contactors and terminal block for any burnt wire signs.

3. Verify all 3 legs of voltage are present at the outgoing side of the Safety contactor. If so, skip to step 6.

   

4. Check safety contactor across all 3 legs. L1 to T1, L2 to T2 and L3 to T3. Each leg check should show close to 0 VAC when closed. If any of the 3 legs show line voltage present (120 VAC, etc.), replace the contactor.

5. If the contactor voltage checks correctly but all 3 legs of voltage are not present, then check terminal block, power cord, and plug/receptacle.

   

6. When heat is activated, check amp draw on all 3 legs coming off the heat contactor going into the terminal block as shown. Troubleshoot the heat contactor by energizing the heat contactor continuously:

   1. Tap Menu Settings.

   2. Tap Service.

   3. Enter code 1122.

   4. Tap Heat System.

   5. Tap Heat Contactor.

   

7. If no amp draw or low amp draw on any one of the 3 legs is present, verify the heat contactor is closing by checking across all 3 legs of the contactor. L1 to T1, L2 to T2 and L3 to T3. Each check should show close to 0 VAC when closed. If any of the 3 legs show line voltage present (120 VAC, etc.), replace the contactor.

8. If all 3 legs of the contactor check correctly, then replace the heating element.

Additional Troubleshooting

1. Check for loose connections at contactors and terminal block for element wires. Ohm out each phase for each element of the element wires at room temp for inconsistencies.

2. If elements have been replaced recently, verify they are wired correctly per wiring diagram.