10 🟡 Repair Required
Rheem Error Code 10: Rheem Code 10 - Air Supply or Exhaust Blockage
⚠️ Your Rheem tankless water heater has detected a blocked air intake or exhaust vent. The unit will not operate until airflow is restored.
How to Fix Rheem Code 10
- Step 1: Go outside and visually inspect the exhaust vent terminal. Remove any visible debris, bird nests, leaves, or ice buildup.
- Step 2: Check that nothing is placed against or blocking the air intake on the unit.
- Step 3: If you have a condensate drain line, make sure it is not frozen or kinked.
- Step 4: Power-cycle the unit by turning it off, waiting 30 seconds, and turning it back on.
- Step 5: If the error returns after clearing the vent, call a licensed technician to inspect the full vent run.
What Does Rheem Error Code 10 Mean?
Indicates blocked air intake or exhaust venting. The unit detects insufficient combustion air supply or restricted exhaust gas flow.
Common Causes of Rheem Code 10
- Blocked or obstructed exhaust vent terminal — bird nests, debris, ice/snow buildup
- Crushed or kinked vent pipe preventing proper exhaust flow
- Intake air filter clogged with dust or lint
- Vent pipe exceeds maximum length or has too many elbows for the model
- Condensation buildup or frozen condensate drain line blocking exhaust
Applicable Rheem Models
Need a Pro to Fix Rheem Code 10?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Rheem Tankless Water Heater Code 10
Combustion Fan Motor OEM: SP20875
Air Intake Filter OEM: SP20127
Exhaust Vent Terminal