E19
State
External Control / BMS Communication Error
State tankless water heater displays E19; unit may not respond to external demand signal.
Advertisements
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Advertisements
Possible Causes
Incorrect external control wiring, Faulty BMS interface module, Misconfigured control settings
How to Fix / Troubleshooting
Safety: Turn off power before modifying control wiring.
- Verify wiring: Compare external control wiring (e.g., enable/disable, setpoint control) to the State wiring diagram. Correct any miswiring.
- Check interface module: If a separate BMS or cascade module is used, ensure it is powered and communicating properly.
- Control settings: Access the installer menu and verify external control mode is enabled and configured per the application.
- Isolate fault: Temporarily disconnect external controls and operate the heater in standalone mode. If E19 clears, the issue is with external control wiring or device.
Advertisements
Repair Difficulty
Medium
3/5
Required Part
External Control Interface Module
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements