Troubleshooting an E-4 Error VIU/OMS/GMU Board Overheating

Overview

The E-4 error indicates that a control-related board is overheating. This can be critical or non-critical depending on the affected component:

• E-4 VIU (Critical): Control panel (VIU) overheating

• E-4 OMS (Non-Critical): Filtration board (OMS) overheating

• E-4 GMU (Critical): I/O board (GMU) overheating

System Impact

• A critical error requests that the heat system be shut off.

• During a critical error, cook cycles cannot be started.

• A non-critical error (OMS) will shut down filtration but cook cycles can still be started.

• For E-4 GMU specifically:

  • The fryer will shut off heat.

  • The induced draft gas blowers will continue to run to cool the vat and surrounding components.

  • This helps reduce temperature and may allow the system to recover.

Temperature limit: All boards may trip at approximately 95°C (203°F).

Call Avoidance Steps

Before dispatching a service technician, guide the customer through these steps:

Check for nearby heat sources

• Ensure no ovens, grills, or other hot equipment are too close to the fryer control area.

• If present, move the heat source or reposition the fryer.

Verify airflow

• Confirm there is proper ventilation around the control panel and filtration area.

• Remove any obstructions blocking airflow.

Power cycle the fryer

• Turn power OFF.

• Wait 1 minute.

• Turn power ON.

Check ambient temperature

• Ensure the area around the control panel or boards is not excessively hot.

If the error clears after these steps, no service is required.

Field Troubleshooting

If call avoidance steps do not resolve the issue, proceed with the following field troubleshooting steps:

Troubleshooting Steps

E-4 VIU (Control Panel Overheat - Critical)

1. Check temperature near the Control Panel (VIU).

• If the area is hot:

1. Perform a power cycle:

1. Turn fryer power OFF.

2. Wait 1 minute.

3. Turn fryer power ON.

4. If error clears, run fryer as normal and verify error does not return and temperatures are normal.

• If the error remains or returns and the area is cool, replace Control Panel (VIU).

E-4 OMS (Filtration Board Overheat - Non-Critical)

1. Check temperature near the OMS Board.

• If the area is hot:

  1. Perform a power cycle:

     1. Turn fryer power OFF.

     2. Wait 1 minute.

     3. Turn fryer power ON.

     4. If error clears, run fryer a normal and verify error does not return and temperatures are normal.

• If the error remains or returns and the area is cool, replace OMS Board.

E-4 GMU (I/O Board Overheat - Critical

1. Check temperature near the GMU Board.

• If the area is hot:

  1. Perform a power cycle:

     1. Turn fryer power OFF.

     2. Wait 1 minute.

     3. Turn fryer power ON.

     4. If error clears, run fryer as normal and verify error does not return and temperatures are normal.

  2. Verify cooling fans are running.

  3. Verify no flame rollout is occurring.

• If the error remains or returns and the area is cool, replace GMU Board.