3 flashes
Easy Fix
Rheem · HVAC Systems & Water Heaters
High Heat Call Active
Quick Answer
Error code 3 flashes on your Rheem HVAC Systems & Water Heaters means: High Heat Call Active. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Verify the thermostat is calling for second-stage or high heat
2
Confirm the gas valve has shifted to high-fire (audible click or visible flame change)
3
No action required if the system is operating normally in high heat
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
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