Installation Guide

TROUBLESHOOTING
20 • Electric Tankless Water Heater
Display Description Action / Solution
E14 4-Chamber models only:
Outlet thermistor open (TH-4).
1. Turn off power to the water heater.
2. Check the connec ons of the thermistor in ques on.
3. Disconnect the thermistor, then reconnect it.
4. Turn on power to the water heater.
5. Does the error code reoccur? If yes, turn off power and replace the
thermistor that is listed in the le -hand column. See “Thermistor
(Temperature Sensor) Replacement” on page 25.
E20 Inlet thermistor shorted.
Replace the temperature sensor that is listed in the le -hand column.
See “Thermistor (Temperature Sensor) Replacement” on page 25.
E21
Shorted
thermistor.
2- and
4-Chamber
models:
TH-1 shorted.
Point-of-use
models:
T-Out shorted.
E22 2-Chamber models:
TH-2 thermistor is shorted.
4-Chamber models:
TH-3 thermistor is shorted.
E23 4-Chamber models only:
TH-2 thermistor is shorted.
E24 4-Chamber models only:
TH-4 thermistor is shorted.
E51
&
E52
Communica ons Failure. The
user interface has lost connec on
with the control board.
Turn off power to the water heater. Contact Technical Support.