Rheem Error Code 10: Rheem Code 10 - Air Supply or Exhaust Blockage

Severity
Warning
Type
digital display
Estimated repair cost: $250 — $600 (parts + labor)
Warning: 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

  1. Step 1: Go outside and visually inspect the exhaust vent terminal. Remove any visible debris, bird nests, leaves, or ice buildup.
  2. Step 2: Check that nothing is placed against or blocking the air intake on the unit.
  3. Step 3: If you have a condensate drain line, make sure it is not frozen or kinked.
  4. Step 4: Power-cycle the unit by turning it off, waiting 30 seconds, and turning it back on.
  5. Step 5: If the error returns after clearing the vent, call a licensed technician to inspect the full vent run.

How to Reset Rheem Code 10

  1. Turn off the unit using the power button on the front panel.
  2. Turn off the gas supply valve.
  3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
  4. Restore power at the breaker, then open the gas valve.
  5. Turn the unit back on. If the error returns, the underlying issue needs repair.

What does 10 mean?

Indicates blocked air intake or exhaust venting. The unit detects insufficient combustion air supply or restricted exhaust gas flow.

Affected Models

Replacement Parts

PartOEM NumberEst. Cost
Combustion Fan Motor SP20875 —
Air Intake Filter SP20127 —
Exhaust Vent Terminal — —

Related Codes on Same Models

CodeDescriptionSeverity
A001 Ignition Failure Warning
A003 Abnormal Ignition Warning
A004 False Flame Detection Warning
A008 Exhaust Temperature High Warning
A011 No Flame Detected Warning
A021 Over-Temperature Warning
A031 Inlet Thermistor Open/Short Warning
A041 Outlet Thermistor Open/Short Warning
A043 Water Level Error Warning
A051 Fan Motor Abnormality Warning