EcoSmart Water Heater Error Codes

Common Symptoms

• EcoSmart unit has no light — looking for what that means
• Green LED is flashing but no hot water is produced
• Solid red LED — unit shut itself off
• Red LED is flashing — looking for cause
• No LED light at all despite unit being plugged in / breaker on
• Unit stopped heating after working fine — LED has changed pattern

Most Likely Causes

1. 1

   Solid Green LED — Unit Is Heating Normally

   A solid (non-flashing) green LED means the EcoSmart ECO unit has detected flow above the 0.3 GPM activation threshold and the heating elements are energized. This is normal operation. If you see a solid green LED but the water is not hot enough, the issue is not the unit's operation — it is likely a demand vs. capacity mismatch (flow rate too high for the unit's kW rating and the cold water temperature entering the unit).

2. 2

   Flashing Green LED — Flow Detected, Not Heating

   A flashing green LED means the flow sensor has detected water movement, but the flow rate is below the 0.3 GPM minimum required to activate the heating elements. Low-flow showerheads (0.5 GPM or less) are the most common cause. Also caused by a partially closed inlet supply valve or a clogged inlet filter screen.

3. 3

   Solid Red LED — Overheat Trip (High-Limit Safety)

   A solid red LED indicates the thermal high-limit safety device has tripped, cutting power to the heating elements to prevent damage. The blue reset button must be pressed to restore operation. Root causes include: flow rate too low (elements overheat without adequate water cooling), inlet water temperature too high (e.g., re-circulating loop), or a failing heating element causing uneven thermal load. Always identify and address the root cause before resetting — a unit that repeatedly trips the high-limit has an underlying problem.

4. 4

   Flashing Red LED — Heating Element Failure

   A flashing red LED indicates the unit has detected a heating element fault — typically an open circuit (burned-out element) or a short. This requires testing each element with a multimeter and replacing failed elements with genuine EcoSmart proprietary elements. The ECO 27 E-01 kit and equivalent model-specific kits include the element and the required proprietary O-ring.

5. 5

   No LED Light — Power Issue

   No LED light at all means the unit is not receiving power. Check all dedicated circuit breakers (one, two, or three depending on model), verify the wire connections at the unit's terminal block are secure, and confirm 240V is reaching the unit with a multimeter. Also check that the wire gauge is correct for the model — undersized wire may have overheated and failed.

Quick DIY Checks

1. 1Step 1 — Identify your EcoSmart model and read the LED: locate the LED indicator on the front of the ECO unit. Note whether it is: (A) no light; (B) solid green; (C) flashing green; (D) solid red; (E) flashing red. For SMARTHEAT point-of-use units: check the power indicator on the unit and confirm the outlet it is plugged into is powered (test with a lamp). A GFCI outlet that has tripped will appear dead — find the nearest GFCI outlet and press the TEST then RESET button.
2. 2Step 2 — No LED light: go to your electrical panel and locate the dedicated breakers for the EcoSmart unit. Breaker count by model: ECO 8, ECO 11 = 1 breaker; ECO 18, ECO 24, ECO 27 = 2 breakers; ECO 36 = 3 breakers. If any breaker is tripped (middle position), push fully to OFF then back to ON. If the breaker holds, verify the LED comes on when a hot tap is opened. If the breaker immediately trips again when the unit tries to heat, there is a shorted element — do not continue resetting. Proceed to element resistance testing in Step 6.
3. 3Step 3 — Flashing green LED (flow detected, not heating): the unit needs minimum 0.3 GPM of flow to activate elements. Open a standard bathroom lavatory faucet (not a low-flow showerhead) at full flow and check if the LED changes to solid green and hot water is produced. If yes, the original fixture has insufficient flow — replace the showerhead or aerator with a higher-flow model (1.5 GPM or higher). If the LED stays flashing green at all fixtures: turn off the unit, check that the cold water supply valve is fully open, and remove and clean the inlet filter screen at the cold water inlet.

1. 4Step 4 — Solid green LED but water not hot enough: this is a capacity vs. demand mismatch, not a fault code. Check: (a) is the temperature dial on the unit set to the desired temperature? (b) what is the incoming cold water temperature? ECO 11 (11kW) raises 1.0 GPM by approximately 40°F — in winter with 40°F incoming water, maximum output is approximately 80°F at 1 GPM. Reduce flow rate or upgrade to a higher-kW ECO model for adequate temperature rise at your required flow rate.
2. 5Step 5 — Solid red LED (overheat trip): press the BLUE RESET BUTTON on the unit. The blue reset button location varies by ECO model — check both the top of the unit and the bottom panel area. After pressing the reset button, turn off the unit's breakers for 30 seconds, then restore power. Open a hot tap and observe whether the LED returns to solid green and hot water flows. If the red LED returns within a few minutes of operation, there is an underlying cause: low flow rate causing element overheating (reduce demand or check inlet screen), or a failing element that needs resistance testing. Do not repeatedly reset without diagnosing the root cause.
3. 6Step 6 — Flashing red LED (element failure): element resistance testing. Turn off ALL dedicated breakers and allow the unit to cool for 10 minutes. Use a non-contact voltage tester to confirm no voltage before opening the unit. Remove the front cover (typically 4 Phillips screws). Locate the heating elements — ECO 11 has 1 element; ECO 18 has 2; ECO 27 has 3; ECO 36 has 4. Disconnect each element's wiring leads and test resistance with a multimeter set to ohms. A healthy element reads 10–30 ohms (varies by element wattage). An open circuit (OL or infinite resistance) = failed element. A reading of 0 ohms (dead short) = shorted element causing breaker trips.
4. 7Step 7 — Element replacement (if resistance test indicates failure): with breakers off and unit cooled, shut off the cold water supply to the unit. Open the nearest hot tap to release line pressure. Use an element wrench (or large socket) to unscrew the failed element counterclockwise. Order the correct EcoSmart element replacement kit for your model: ECO 27 uses the E-01 kit; other models have model-specific kits — confirm the correct kit via EcoSmart's website or call 1-877-474-6473. Each kit includes the element AND the proprietary O-ring. Drain any water from the element chamber, install the new element with the included O-ring (never reuse the old O-ring), hand-tighten then snug 1/4 turn. Restore water, verify no leaks, then restore power.
5. 8Step 8 — Full breaker sizing reference table (ECO 8 through ECO 36): use this table to verify your electrical installation matches spec. ECO 8 (8kW): 1×40A breaker, 8 AWG wire. ECO 11 (11kW): 1×40A breaker, 8 AWG wire. ECO 18 (18kW): 2×40A breakers, 8 AWG wire per circuit. ECO 24 (24kW): 2×40A breakers, 8 AWG wire per circuit. ECO 27 (27kW): 2×40A breakers, 8 AWG MINIMUM per circuit. ECO 36 (36kW): 3×40A breakers, 6 AWG wire per circuit. All ECO models require 240V single-phase dedicated circuits. Wire gauge must meet or exceed the minimums listed — undersized wire is the root cause of many overheating and no-heat complaints.

Repair vs Replace

Recommended Tools & Parts

• EcoSmart Replacement Element Kit (ECO 27 E-01 and Model-Specific)

  Genuine EcoSmart heating element replacement kit including proprietary copper element and correct O-ring. ECO 27 uses the E-01 kit. Other models use model-specific kits — confirm via EcoSmart website or call 1-877-474-6473. Do NOT use generic elements.

  $80–$150 per kit

  Buy on Amazon →

• Digital Multimeter

  Required for testing heating element resistance (open circuit = failed element, 0 ohms = shorted element) and verifying 240V power at the terminal block. Any multimeter with a resistance (ohms) range works.

  $15–$35

  Buy on Amazon →

• Non-Contact Voltage Tester

  Mandatory safety tool for confirming all 240V power is off before opening the EcoSmart ECO unit. A non-negotiable safety step on 240V appliances with multiple breakers.

  $15–$30

  Buy on Amazon →

• Element Wrench (Water Heater Socket Wrench)

  Specialized socket wrench for removing and installing threaded heating elements. Required for EcoSmart ECO element replacement — standard wrenches do not grip element flanges correctly.

  $15–$25

  Buy on Amazon →

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

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