7
Rheem Low Flame Sense / Flame Loss

Status LED flashes 7 times; furnace may start then shut down, or not start at all

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Dirty flame sensor, Poor burner ground, Low gas pressure, Partially plugged burner orifice

How to Fix / Troubleshooting

Safety first: Turn off power and gas before removing burner access panels.

  • Clean flame sensor: Remove the flame sensor and gently polish the rod with fine steel wool until shiny. Reinstall and ensure the sensor is fully in the flame path.
  • Check ground connections: Tighten all ground screws on the burner assembly and control board. Ensure the furnace cabinet is properly grounded to the electrical system.
  • Inspect burners: Remove burners if accessible and check for rust, debris, or spider webs in the orifices. Clean with compressed air; do not enlarge orifices.
  • Observe flame: With power restored, watch the burner flame through the sight glass. Flames should be steady and mostly blue. Yellow, lifting, or noisy flames can indicate gas pressure or combustion issues that require professional adjustment.

If the furnace lights but shuts off after a few seconds repeatedly, and cleaning the sensor does not help, the gas valve or control board may be faulty.

Advertisements

Repair Difficulty

Hard 4/5

Required Part

Flame Sensor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements