The control module or User Interface Module is the feature that is built in the American heat pump, and is conveniently located at the front of the unit. The User Interface Module through the advanced electronics allows the following functions; setting up and adjustments of the hot water output temperature and operation modes, diagnostics and monitoring of the unit parameters.
As said, the control module allows an easy
temperature control, by using the provided Up and Down buttons, so the
hot water temperature can be adjusted from 95F to 140F.
Easy-to-read LCD screen offers useful textual and numerical
information such as the current outgoing hot water temperature which
can be shown either in Fahrenheit or Celsius, also the diagnostic codes
if there is a problem with the unit. There is also information message
such as when the unit goes into the defrosting mode, the message will
display "ICE" on the screen. Also a message "HPO" on the screen means
that the water temperature condition is out of the heat pump operation
Below the display screen, there are four indication lights that shows which of the operation modes is active: efficiency, hybrid, electric or vacation. This can be activated or changed by pressing the button Mode/Enter.The same button, when pressed for several seconds, changes the setting to Power Saver mode or disables it, so the unit is managed by the grid or any other management program.
A system diagnostic usually runs when power the unit ON and for several minutes.
The most common diagnostic codes that can be seen on the display of the User Interface Module are the following:
EUC - Problem with the upper heating element
ELC - Problem with the lower heating element
SF - Dirty air filter, so the filter needs to be cleaned or replaced
ECF - Heat pump compressor problem
E20 or E21 - Problem with the upper temperature sensor
E30 or E31 - Problem with the lower temperature sensor
E50 or E51 - Problem with the HP suction temperature sensor
E10 or E11 - Problem with the HP coil temperature sensor
E40 or E41 - Problem with the HP discharge temperature sensor
Edr - Storage water tank is not full
EPL - Voltage is too low
EDH - HP discharge temperature is too high
EoF - Problem with the condensate pump
ECL - HP suction pressure is too low
EEE - EEPROM failure
ECC - Problem with the compressor
ICE - Defrosting cycle
HPO - Out of the operation range
"-", "--", "---" - diagnostic check. It is displayed during the system diagnostic, when power is ON and it lasts for several minutes.
Note: Picture from americanwaterheater.com