Rheem Water Heater Error Codes: P1, P7, E1, 13, 29 — Causes & Troubleshooting

Common Symptoms

• Error code on the Rheem EcoNet or digital display
• No hot water or inconsistent water temperature
• Pilot light won't stay lit (gas models)
• Water too hot or thermostat won't respond
• Water heater not turning on or cycling off repeatedly

Most Likely Causes

1. 1

   P1 — Inlet Sensor Fault

   The inlet water temperature sensor has an open or short circuit. This sensor monitors the temperature of cold water entering the tank. A failed sensor prevents the unit from accurately modulating heat output.

2. 2

   P7 — Outlet Sensor Fault

   The hot water outlet temperature sensor has failed. Without accurate outlet temperature readings, the water heater cannot confirm it's reaching the set temperature.

3. 3

   E1 — Upper Heating Element Fault (Electric)

   The upper heating element has burned out or has a shorted circuit. Electric water heaters have two elements — the upper element heats newly added cold water, and the lower element maintains overall temperature.

4. 4

   Code 13 — Thermopile Voltage Low (Gas)

   The thermopile (the device that generates voltage to power the gas valve on non-pilot ignition models) is generating insufficient voltage. Causes: sediment buildup on the thermopile, a weak thermopile, or a failing gas control valve.

5. 5

   Code 29 — Condensate Drain Blocked (Power Vent / Hybrid)

   On condensing or hybrid heat pump water heaters, code 29 means the condensate drain line is clogged with mineral deposits or debris, causing water to back up into the unit.

Quick DIY Checks

1. 1For E1 (electric): Turn off the water heater's circuit breaker. Remove the upper access panel and insulation. With a multimeter set to resistance, test the upper heating element terminals — a reading of OL (open) means the element is burned out. Heating elements are $15–$30 and take 30 minutes to replace.
2. 2For P1/P7 sensor faults: Locate the temperature sensor — on most Rheem models it's a probe inserted into the tank top. With the unit powered off, unplug the sensor connector and test resistance with a multimeter (should read ~10k ohms at 70°F). A reading of 0 or OL means replacement is needed.
3. 3For code 13 (thermopile): Drain 1–2 gallons from the tank to flush sediment. Attempt a manual pilot re-light as per the label instructions. If the pilot stays lit but code 13 persists, check the thermopile output voltage by testing across the thermopile terminals with a multimeter — should read 650–850mV with the pilot lit. Below 400mV means replace the thermopile.

Repair vs Replace

Recommended Tools & Parts

• Rheem Electric Water Heater Heating Element

  Replacement upper or lower heating element for Rheem electric water heaters. Available in 4500W and 5500W — match your existing element rating.

  $15–$30

  Buy on Amazon →

• Rheem / Generic Water Heater Thermopile

  Replacement thermopile for Rheem gas water heaters. Fixes code 13 low voltage faults when pilot stays lit but valve won't open.

  $20–$40

  Buy on Amazon →

• Water Heater Temperature Sensor

  Replacement temperature sensor for Rheem EcoNet and digital display water heaters. Fixes P1 and P7 sensor fault codes.

  $20–$50

  Buy on Amazon →

• Non-Contact Voltage Tester

  Essential safety tool before working on 240V electric water heaters. Confirms power is off before touching any terminals.

  $15–$30

  Buy on Amazon →

Links are Amazon affiliate links (tag: fixitfastai-20). Prices are estimates.

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