Girard Water Heater: “E3”
warning RV water heater fault codes
What it means
The ECO (energy/over-temperature cut-off) thermostat opened, either before ignition or during operation. This is the high-limit safety device tripping, normally because outlet water got too hot (around 140°F).
Most likely causes
- Outlet water temperature climbed past the high-limit (≈140°F / 60°C) most likely
- Low or no water flow causing heat to build up in the heat exchanger common
- ECO thermostat failed open / out of spec less common
- Loose or corroded ECO wiring connection less common
Safe checks you can do yourself
- Let cool water flow through the heater for a minute or two to bring the heat exchanger temperature down.
- Check that the water filter/screen and plumbing are not restricting flow.
- Confirm the temperature setting is not maxed unnecessarily.
- Inspect the ECO connector for a loose/corroded contact (with power off).
How to reset / clear E3
- Run cold water through the system to cool it.
- Turn the heater off at the panel, wait ~10 seconds, and turn it back on.
- Restart hot water flow and watch for the code to clear.
When to call a technician
If the ECO trips repeatedly even with good water flow and a cooled heater, have a technician test/replace the ECO thermostat and check the heat exchanger.
Applies to
GSWH-2 · 2GWHAM
FAQ
What does Girard Water Heater code "E3" mean?
The ECO (energy/over-temperature cut-off) thermostat opened, either before ignition or during operation. This is the high-limit safety device tripping, normally because outlet water got too hot (around 140°F).
How do I reset Girard Water Heater E3?
Run cold water through the system to cool it. Turn the heater off at the panel, wait ~10 seconds, and turn it back on. Restart hot water flow and watch for the code to clear.
What is the most common cause of E3 on a Girard Water Heater?
The most likely cause is outlet water temperature climbed past the high-limit (≈140°f / 60°c).
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Sources
- Girard Products GSWH-2 Technical Manual — GSWH-2 Technical Manual, E3 ECO open before ignition or during normal operation (Girard Products / ManualsLib)
- Girard GSWH-2 Tankless Water Heater Technical Manual and Troubleshooting Guide — Fault code list, E3 ECO open, outlet temperature exceeding ~140°F (Manuals.plus)
Note: The 140°F figure is cited as ~140°F / ~60°C; one source notes 79°C — there is some inconsistency in the threshold value across reproductions of the manual, so treat the exact number as approximate.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.