8 flashes
Moderate
Rheem · HVAC Systems & Water Heaters
Flame Lost During Operation
Quick Answer
Error code 8 flashes on your Rheem HVAC Systems & Water Heaters means: Flame Lost During Operation. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Remove and clean the flame sensor with fine emery cloth
2
Measure flame current during operation with a microamp meter (should be above 1.5 microamps)
3
Verify the furnace chassis has a solid ground connection
4
Check gas pressure stability during operation with a manometer
5
Inspect the flue terminal for proper wind cap installation to prevent downdrafts
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Flame sensor
Emery cloth
Flame sensor gasket
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