Troubleshooting code
Back to all DHC102HW*(L,M,H,X,Y,Z)A***E error codes
Pressure switch fault. Use this page to document the issue and prepare for service. GreenFlow should handle diagnosis for electrical, refrigerant, lockout, or recurring conditions.
What the code means
The Trane Precedent gas heat fault-code table identifies 3 flash as pressure switch failed to open or close, with pressure switch, combustion blower, hose, flue fitting, airflow, or board concerns listed as possible issues.
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.
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View service detailsThe Trane Precedent gas heat fault-code table identifies 3 flash as pressure switch failed to open or close, with pressure switch, combustion blower, hose, flue fitting, airflow, or board concerns listed as possible issues.
The Trane source used for this page associates Ignition 3 Flash with "Pressure switch fault". Match the visible display text, LED pattern, or alert wording to the exact code whenever possible.
This code is grouped under precedent gas heat ignition board in the source-backed Trane troubleshooting data.
Source-backed Trane Commercial HVAC Help Center Precedent gas heat fault-code table for ignition-board diagnostics.
Yes. The Trane source row for this item is based on a displayed LED or flash pattern. Count the pattern exactly and compare it with the documented Ignition 3 Flash entry before interpreting the fault.
The Trane source row places this code in a pressure-related system area: Precedent gas heat ignition board. Do not treat a pressure-safety code as a thermostat-only issue.
The Trane source row places this code in a combustion, ignition, limit, flame, or pressure-switch safety context. These codes should be interpreted from the exact equipment board and documented flash pattern.
The Trane source row points to precedent gas heat ignition board. Record the exact code and visible alert text before any reset so the control history is not lost.
Capture the exact code, any displayed alert text, the model and serial number, thermostat or control status, operating mode, symptoms, and photos of the display or LED pattern before the alert history is cleared.
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