State Water Heater E64 Error — What It Means
The E64 error code on State water heaters is not consistently documented across all State models in available manufacturer literature. State produces both gas and electric water heaters with different control systems, and each platform uses its own diagnostic codes. Without your specific model number and control board type, the exact meaning of E64 cannot be verified from State’s published materials.
In general appliance fault patterns, codes in the E60–E69 range often indicate heating circuit abnormalities, control board communication faults, or sensor issues. However, applying that general pattern to your State water heater without the model-specific service manual risks misdiagnosis. To get the accurate definition and repair path, locate the full model number on the rating plate (usually on the side of the tank near the top) and consult the owner’s manual or wiring diagram that shipped with the unit, or contact State’s technical support with the model number in hand.
Before You Replace Anything
Because E64’s exact meaning varies by State model, some owners replace the control board or heating element without first checking for loose wiring, tripped high-limit switches, or incorrect sensor readings. Always verify the fault definition in your model’s service literature and test voltage, continuity, and resistance at the suspect component before ordering parts.
Common Causes
- Loose or corroded wiring (~30%) Vibration, moisture, or age can loosen spade connectors at the thermostat, heating elements, or control board, creating an open circuit the controller reads as a fault.
- Tripped high-limit thermostat (~25%) Overheating trips the manual-reset high-limit switch, which interrupts the heating circuit and may trigger a code until the button is pressed.
- Failed temperature sensor or thermistor (~20%) An out-of-range resistance reading from the sensor tells the control board that the circuit is faulty, even when the heater itself is fine.
- Control board communication error (~15%) Internal microprocessor faults, corrupted firmware, or power-supply glitches can log spurious codes that clear after a full power cycle.
- Heating element fault (electric models) (~10%) A shorted or open heating element, or a grounded element touching the tank wall, may be flagged by the control board as a circuit abnormality.
Quick Diagnosis
Answer these to narrow it down fast.
Does the code clear after a 60-second power reset at the breaker?
No: The fault is persistent. Proceed to inspect wiring and test components as described in the steps below.
Is there a red high-limit reset button on the thermostat or upper element flange, and does it click when pressed?
No: The high-limit is either already reset or your model does not have a manual button. Move on to checking sensors and element continuity.
Do you have the full model number and can you find the service manual or wiring diagram?
No: Call State customer service or a licensed technician with your model and serial number to confirm the code definition before replacing any parts.
Step-by-Step Fix
- Turn off power at the circuit breaker (electric) or set the gas valve to pilot/off (gas). Wait 60 seconds, then restore power and observe whether the E64 code reappears.
- Locate the rating plate on the side of the tank and write down the complete model number, serial number, and control-board part number if visible.
- Download or retrieve the owner’s manual from State’s website using the model number, and turn to the diagnostic-code table to confirm what E64 means for your specific unit.
- Inspect all electrical connections at the control board, thermostats, sensors, and heating elements (electric models). Tighten or clean any corroded spade terminals and reseat push-on connectors.
- Check the high-limit reset button (usually a red button on the thermostat or upper element flange). Press firmly until you hear or feel a click. If it was tripped, the code may clear immediately.
- Test sensor resistance with a multimeter if the manual identifies E64 as a sensor fault. Disconnect the sensor leads, measure resistance, and compare to the temperature-resistance table in the manual.
- Replace the identified component (sensor, thermostat, heating element, or control board) only after confirming it is out of specification or the manual’s diagnostic flow points to that part. Record the new part number and reset any error memory as directed.
Parts Often Needed
| Part | Notes |
|---|---|
| Temperature sensor or thermistor | Amazon | Match the connector type and resistance curve to your model; State and A.O. Smith sensors are often interchangeable within the same control platform. |
| Upper thermostat with high-limit | Amazon | Electric models only; verify voltage rating (120 V or 240 V) and whether your unit uses a single- or dual-element stat. |
| Electronic control board | Amazon | Last-resort part; confirm the board part number on the existing unit and check that E64 is not caused by a sensor or wiring issue first. |
When to Call a Pro
Call a licensed plumber or water-heater technician if you cannot locate the model-specific meaning of E64, if the fault persists after a power reset and visual inspection, or if you are uncomfortable working with 240-volt electric circuits or gas controls. A technician has access to State’s service bulletins, can measure voltage and resistance at each component, and carries the correct replacement parts on the truck. Also call a pro if the high-limit keeps tripping repeatedly, which signals a dangerous overheating condition that requires immediate diagnosis of the thermostat, relief valve, or sediment buildup.
Rough cost: A pro service call runs about $150–350.