Rheem heat pump water heater
Rheem ProTerra 120V plug-in error codes
Covers: ProTerra 120V Plug-in Heat Pump Water Heater (Dedicated Circuit; and Shared Circuit with HydroBoost)
Every code listed in Rheem's own manual for this series, with what it means and what Rheem says to do. Last checked 2026-10-03.
Is this your model? For the 120V plug-in models: dedicated circuit (e.g. PROPH50 T0 RH120) and shared circuit with HydroBoost (e.g. PROPH65 T0 RH120-MSO, XE50T10HM00U0), as linked from Rheem's product pages. Same text display and buttons as the 240V Gen V models.
| Code | Label | What the manual says it means |
|---|---|---|
| A004 | Comp.Shutdown: Discharge-Suction Trip | Heating source defaults to elements due to compressor malfunction |
| A005 | Compressor Shutdown: Discharge Temp High | Heating source defaults to elements due to compressor malfunction |
| T005 | Compressor Shutdown: Discharge Temp High | Heating source defaults to elements due to low airflow |
| A006 | Suction Temperature Too Low | Heating source defaults to elements due to compressor malfunction |
| T006 | Suction Temperature Too Low | Heating source defaults to elements due to compressor malfunction |
| T009 | Compressor wiring may be faulty | Heating source default to elements due to compressor malfunction |
| A009 | Compressor wiring may be faulty | Heating source default to elements due to compressor malfunction |
| A101 | Suction Temperature Sensor Failure | Heating source defaults to elements due to heat pump temperature sensor malfunction |
| A102 | Ambient Temperature Sensor Failure | Heating source defaults to elements due to heat pump temperature sensor malfunction |
| A103 | Lower Heater Temp Sensor Failure | Lower tank temperature sensor malfunction. Heater disabled. |
| A104 | Upper Heater Temp Sensor Failure | Lower tank temperature sensor malfunction. Heater disabled. |
| A105 | Evaporator Temp Sensor Failure | Heating source defaults to elements due to heat pump temperature malfunction. |
| A106 | Discharge Temp Sensor Failure | Heating source defaults to elements due to heat pump temperature malfunction. |
| A107 | Water Detected on Floor: Check For Leaks | Water is detected in the drain pan |
| A108 | Condensate Blocked: Unclog Line | Heating source defaults to elements due to condensate drain blockage |
| A130 | Unit Off/Air Temp Freezing: Enable Unit | Ambient temperature is below freezing. --FREEZE WARNING |
| T131 | Clean Filter Reminder | Air filter routine maintenance reminder |
| T132 | Water Heater difficulty satisfying demand | Water heater can not satisfy demand |
| A120 | Shutoff Valve Can't Close Error | Shut-Off Valve malfunction |
| A121 | Shutoff Valve Can't Open Error | Shut-Off Valve malfunction |
| A122 | Shutoff Valve Inputs in Error | Shut-Off Valve malfunction |
| A123 | Shut-Off Valve Not Installed | Shut-Off Valve malfunction |
| A200 | High Water Temp! [ECO] Call Tech Service | ECO Tripped. Heater Disabled |
| T300 | Water vor Not Installed [sic; as printed] | Water Leak Sensor Not Installed |
| A502 | Time Clock needs to be programmed | Controller malfunction. Heater disabled. |
| A503 | Time Clock not advancing time properly | Controller malfunction. Heater disabled. |
| T504 | WiFi Chip Communication Error | Controller malfunction. Heater disabled. |
| A900 | Controller Fault: Call Tech Service | Controller malfunction. Heater disabled. |
| T901 | Controller Fault: Call Tech Service | Controller malfunction. Heater disabled. |
| A902 | Controller Fault: Call Tech Service | Controller malfunction. Heater disabled. |
| A903 | Controller Fault: Call Tech Service | Controller malfunction. Heater disabled. |
| A904 | Controller Fault: Call Tech Service | Controller malfunction. Heater disabled. |
| A905 | Controller Fault: Call Tech Service | Controller malfunction. Heater disabled. |
| A906 | Power Board Temp. Protection Sensor Failure | Controller getting too hot. |
Rheem's manual for this series does not list error codes; see the troubleshooting section below.
Safety first
- CAUTION: For your safety DO NOT attempt repair of electrical wiring, thermostats, or other safety devices. Refer repairs to qualified service personnel. (p.28)
- ECO reset: "Disconnect all power to unit before starting maintenance." CAUTION: The cause of the high temperature condition must be investigated by qualified service technician and corrective action must be taken before placing the water heater in service again. (p.19)
- WARNING: If the water heater has been subjected to fire, flood or physical damage, disconnect all power to water heater, and DO NOT operate the water heater again until it has been checked by a qualified service technician. (p.19)
- NOTICE: DO NOT use this appliance if any part has been under water. Immediately call a qualified installer or service agency to replace a flooded water heater. DO NOT attempt to repair the unit! It must be replaced. (p.19)
- DO NOT turn on water heater unless it is filled with water. DO NOT turn on water heater if cold water supply shut-off valve is closed. (p.19)
- CAUTION: Hydrogen gas can be produced in a hot water system ... that has not been used for a long period of time (generally two weeks or more). HYDROGEN GAS IS EXTREMELY FLAMMABLE!! ... open the hot water faucet for several minutes at the kitchen sink before using any electrical appliance connected to the hot water system ... DO NOT smoke or use an open flame near the faucet at the time it is open. (p.19)
- CAUTION: Shut off power to the water heater before draining water. DANGER: Before manually operating the relief valve, make certain no one will be exposed to the hot water released by the valve; the water may be hot enough to present a scald hazard. (p.26)
- NOTICE: If the temperature and pressure relief valve discharges periodically, this may be due to thermal expansion in a closed water system. Contact the water supplier or your plumbing contractor. DO NOT plug the relief valve outlet. (p.26)
- DANGER: Water temperature over 125°F (52°C) can cause severe burns instantly or death from scalds. (p.3)
- Alarm table 'What to Do' steps include service-technician procedures (meter readings, board/sensor replacement); refer repairs to qualified service personnel per the manual's caution. (pp.28-31)
From the manufacturer's manual for this series.
Troubleshooting without a code
Rumbling noise
Likely cause: Water conditions in your home caused a build up of scale or mineral deposits in the water heater.
What to do: Allow a few quarts of water to run from drain valve to remove sediment settlings.
Relief valve producing popping noise or draining
Likely cause: Pressure build up caused by thermal expansion in a closed system
What to do: This is an unacceptable condition and must be corrected. Contact the water supplier or plumbing contractor on how to correct this. DO NOT plug the relief valve outlet
Not enough or no hot water
Likely cause: Water usage may have exceeded the capacity of the water heater.
What to do: Wait for the water heater to recover after an abnormal demand
Not enough or no hot water
Likely cause: A fuse is blown or a circuit breaker tripped
What to do: Replace fuse or reset circuit breaker
Not enough or no hot water
Likely cause: Electric supply may be off
What to do: Confirm electric supply to water heater and see installation section of this manual.
Not enough or no hot water
Likely cause: The thermostat may be set too low.
What to do: See the Temperature regulation of the water heater section of this manual
Not enough or no hot water
Likely cause: Leaking or open hot water faucets
What to do: Make sure all faucets are closed
Not enough or no hot water
Likely cause: Electric service to your home may be interrupted
What to do: Contact the local electric utility.
Not enough or no hot water
Likely cause: Improper wiring.
What to do: See the Installing the water heater section of this manual.
Not enough or no hot water
Likely cause: Manual reset limit (ECO)
What to do: See the Temperature regulation of the water heater Refer to page 3 for more information.
Not enough or no hot water
Likely cause: Cold water inlet temperature may be colder during the winter months
What to do: This is normal. The colder inlet water takes longer to heat.
Not enough or no hot water
Likely cause: Not enough air exchange for Efficient Heat Pump Operation.
What to do: If air temperature drops more than 15°F (8°C) during Heat Pump Operation, more air circulation around heater is needed.
Water is too hot
Likely cause: The thermostat is set too high.
What to do: See the Temperature regulation of the water heater section of this manual
Temperature limiting control (ECO) tripped (manual reset)
Likely cause: The temperature limiting control (ECO) is located in upper cavity cover in contact with the tank surface. If for any reason the water temperature becomes excessively high, the temperature limiting control (ECO) breaks the power circuit to the heating system. Once the control opens, it must be reset manually.
What to do: CAUTION: The cause of the high temperature condition must be investigated by qualified service technician and corrective action must be taken before placing the water heater in service again. To reset the temperature limiting control: Disconnect all power to unit before starting maintenance. Remove the upper cavity cover and insulation. Press the red RESET button. Replace the insulation, jacket access panel and plastic housing before turning on the power to the water heater.
Owner maintenance
clean air filter
How often: when "Clean filter reminder" alert appears (alarm T131)
It is recommended to clean the filter on top of the heat pump when "Clean filter reminder" alert appears. Clean by washing with mild detergent and water. Dry and replace. Remove the filter by lifting up, then replace by lowering back into the filter slot on top of the unit.
condensate drain cleaning
How often: at least once a year
Pour a cup of bleach in the access opening of the condensate drain to kill any algae, mold, or mildew that has formed in the pipe. Ensure the condensate can flow freely; unclog if needed.
drain sediment from tank
How often: every month
It is suggested that a few quarts of water be drained from the water heater's tank every month to clean the tank of these deposits [hard water deposits that accumulate in the bottom of the tank].
test temperature & pressure relief valve
How often: at least once a year
Lift and release the lever handle on the temperature pressure relief valve, located on the side of the water heater, to make certain the valve operates freely. Allow several gallons to flush through the discharge line to an open drain. (DANGER: make certain no one will be exposed to the hot water released by the valve; release into a suitable drain.)
draining the water heater
CAUTION: Shut off power to the water heater before draining water. Turn off the cold water supply. Open a hot water faucet or lift the handle on the relief valve to admit air to the tank. Attach a garden hose to the drain valve on the water heater and direct the stream of water to a drain. Open the valve.
noise check
If the hissing or singing sound level increases excessively, Contact a qualified installer or plumbing contractor to inspect.
anode rod
The anode rod is slowly consumed. NOTICE: DO NOT remove the anode rod from the water heater's tank. Operation with the anode rod removed will greatly shorten the life of the glass lined tank and will exclude warranty coverage. (Rotten egg odor: water with high sulfate and/or mineral content together with cathodic protection can produce hydrogen sulfide odor; chlorination of the water supply should minimize the problem.)
vacation / extended shut-down
How often: if idle for an extended period
The power and water to the appliance should be turned off to conserve energy and prevent a build-up of dangerous hydrogen gas. The water heater and piping should be drained if they might be subjected to freezing temperatures. After a long shut-down period, the water heater's operation and controls should be checked by qualified service personnel. Make certain the water heater is completely filled again before placing it in operation.