What the code means
E7.2: Redundant relay energized when it should be off
The RunTru by Trane A952V error-code table identifies E7.2 when the redundant relay HLO output is energized when it should not be.
Troubleshooting code
Back to all A952V040BU3SB error codes
Trane A952V040BU3SB E7.2 troubleshooting
Redundant relay energized when it should be off. Use this page to document the issue and prepare for service. GreenFlow should handle diagnosis for electrical, refrigerant, lockout, or recurring conditions.
Safe checks before calling
- Confirm the thermostat is on, set correctly, and calling for heating or cooling.
- Check the air filter and visible return-air path for obvious airflow restrictions.
- Look around the outdoor unit for leaves, snow, ice, or other visible obstructions without opening the cabinet.
- Take photos of the thermostat, outdoor unit, nameplate, and any visible flash pattern before scheduling service.
When to stop and call GreenFlow
Call GreenFlow if the code repeats, the system is locked out, heating or cooling is not restored, there is ice buildup, electrical odor, unusual noise, or any issue involving pressure switches, sensors, wiring, refrigerant, reversing-valve operation, or warranty coverage.
Share the visible code, model and serial number if available, photos, current symptoms, and whether the issue affects heating, cooling, or both.
E7.2 questions
What does E7.2 mean on a Trane A952V040BU3SB?
The RunTru by Trane A952V error-code table identifies E7.2 when the redundant relay HLO output is energized when it should not be.
What should I safely check before scheduling service?
Check thermostat status, filter condition, visible outdoor-unit obstructions, and take photos of the flash pattern and nameplate. Do not open electrical panels or refrigerant-side components.
When should GreenFlow handle this code?
Call GreenFlow if the code repeats, the system is locked out, heating or cooling is not restored, there is ice buildup, electrical odor, unusual noise, or any issue involving pressure switches, sensors, wiring, refrigerant, reversing-valve operation, or warranty coverage.
Need help with this code?
GreenFlow can review the code, photos, equipment access, and symptoms before scheduling the right next step.
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