Bell and Gossett A03

What does Bell and Gossett A03 mean?

A03 is a derating alarm on the e-90E Smart Pump. The pump continues to run but the drive is automatically reducing motor output to protect the power electronics from thermal damage. Derating occurs when the drive or motor temperature is elevated but has not yet reached the locking error threshold. The pump's performance is reduced until temperatures return to normal.

Symptoms

• Pump continues to run but the STATUS LED alternates flashing green and orange.
• A03 alarm code alternates with the normal running display.
• Pump may not achieve the required setpoint pressure or flow at reduced output.
• Alarm clears automatically when temperatures drop.

Common causes

• Ambient temperature around the drive enclosure is too high.
• Water temperature in the system exceeds the pump's rated maximum.
• Pump operating at high load for extended periods in a warm environment.
• Insufficient ventilation restricting heat dissipation from the drive.

Diagnostic steps

1. 01

   Check ambient air temperature

   Measure the air temperature at the drive location. Confirm it is within the rated maximum shown on the motor data plate. If temperatures are excessive, improve ventilation or relocate the pump.

2. 02

   Check system fluid temperature

   Verify that the pumped fluid temperature is within specification. High-temperature water increases the thermal load on the pump's internal components and can trigger derating even when ambient air temperature is acceptable.

3. 03

   Reduce system load if possible

   If the pump is operating at maximum load continuously, consider reducing demand on the circuit temporarily. In multi-pump MSE or MSY systems, verify that all pumps in the group are active and sharing the load.

4. 04

   Improve ventilation around the motor

   Remove any lagging, insulation, or enclosed cabinets restricting airflow around the motor and drive body. Confirm clearances meet the minimum required for convective cooling.

5. 05

   Monitor and confirm alarm clears

   Once temperatures return to the operating range, A03 will clear automatically. Monitor parameter P13 (Power Module Temperature) to confirm thermal levels stabilize.

When to call a professional

Call a technician if A03 persists in a properly ventilated environment with fluid and ambient temperatures within specification. Persistent derating under normal conditions indicates a failing thermal sensor, deteriorating drive components, or insufficient drive sizing for the application — all requiring engineering evaluation and possible equipment replacement.