15 🟡 Repair Required
Ruud Error Code 15: Inlet Temp Sensor Fault
⚠️ Your Ruud tankless water heater has detected a problem with its inlet water temperature sensor and has shut down to prevent potential issues. You'll need to troubleshoot or call a technician to get hot water again.
How to Fix Ruud Code 15
- Step 1: Check the display periodically to see if the error clears itself. Sometimes transient electrical noise can cause false errors.
- Step 2: If you are comfortable, check the wiring connections to the water heater. Make sure the power is off. Look for any loose or corroded connections. Do not disassemble anything, just visually inspect.
- Step 3: If the error persists, contact a qualified HVAC technician to diagnose and repair the issue.
What Does Ruud Error Code 15 Mean?
The '15' error code on your Ruud tankless water heater indicates a fault with the inlet water temperature sensor. This sensor is responsible for monitoring the temperature of the water entering the unit. The control board uses this information to regulate the burner and ensure proper operation. If the sensor is faulty, the water heater may not be able to accurately control the water temperature, potentially leading to overheating or inefficient operation. Because the unit can't verify safe operation, it locks out until the issue is resolved. This protects the unit from damage and, more importantly, protects you from scalding water.
Common Causes of Ruud Code 15
- Faulty inlet water temperature sensor
- Loose or corroded wiring connections to the sensor or control board
- Damaged wiring harness leading to the sensor
- Control board failure
- Scale buildup on the sensor, insulating it from the water
Applicable Ruud Models
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Find a Licensed Tech Near You →Replacement Parts for Ruud HVAC System Code 15
Inlet Water Temperature Sensor OEM: REU6109
Control Board