Fault codes / Suburban tankless / E3
Suburban tankless code E3
What it means: High limit (ECO) tripped.
What to check
Open the small access panel on the unit and press the reset button on the thermal disc. Find out why it overheated: scale, low flow, a set point too high, or a fan problem.
Tech detail
Repeat E3 with good flow is a bad flow sensor or a clogged heat exchanger.
Learn the system
Practice it on a service call
Guided diagnosis
Other Suburban tankless codes
- Suburban tankless code E0 Outlet temperature probe open or shorted
- Suburban tankless code E1 Ignition failure: no flame after 3 tries
- Suburban tankless code E2 False flame: flame sensed before startup
- Suburban tankless code E4 Inlet temperature sensor open or shorted
- Suburban tankless code E5 Fan failure: no speed signal
- Suburban tankless code E6 Over temperature at the outlet
- Suburban tankless code E7 Gas valve circuit open or shorted
- Suburban tankless code E8 Pressure switch stuck closed or disconnected
- Suburban tankless code E9 Recirculation pump will not prime (RL models)
- Suburban tankless code En Ran continuously for more than 20 minutes
- Suburban tankless code EC Lost communication with the controller
Full field guide: Suburban IW60 and ST tankless water heater
Codes come from the maker manuals and public service sheets. Your model's own chart always wins, and LP and 120 volt work belongs to a qualified technician.