Rheem RGRA-07EMAES Error Code 4 Blinks: Pressure Switch Circuit Closed
What Does Code 4 Blinks Mean?
A 4-blink pattern on the Rheem RGRA-07EMAES's green STATUS LED indicates that the pressure switch circuit is closed when the control board expects it to be open. The board checks the pressure switch before starting the induced draft motor (IDM) — if the switch is already closed at that point, it signals a fault.
The pressure switch is a safety device that monitors whether the inducer motor is creating adequate draft to properly vent combustion gases. When the switch contacts stick or weld closed, the control board cannot rely on the switch to accurately report venting conditions, so it prevents the furnace from starting.
A technician should check the pressure switch contacts for continuity and replace the switch if the contacts are stuck. The wiring should be inspected for shorts that could bypass the switch. Additionally, the pressure sensing hoses and switch housing should be checked for water or moisture, which can cause the diaphragm to stick in the closed position. For twinned units, the technician should verify the issue is isolated to the affected unit.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace will not start and the STATUS LED blinks 4 times
- Moisture or condensation is visible near the pressure switch
- The code persists after the furnace has been power-cycled
✓ Verified against manufacturer service manual — March 2026