f6
Moderate
Rheem · HVAC Systems & Water Heaters
Vent Blocked (Tankless Water Heater)
Quick Answer
Error code F6 on your Rheem HVAC Systems & Water Heaters means: Vent Blocked (Tankless Water Heater). This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Inspect the exhaust vent pipe along its entire length for blockages
2
Check the vent termination outside for ice, debris, or snow accumulation
3
Verify the vent length and number of elbows does not exceed the manufacturer's maximum
4
Inspect the combustion air intake pipe for restrictions
5
Clear any blockages found and verify the unit operates normally after clearing
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
Vent pipe sections (if damaged)
Vent termination cap
Bird screen
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