How to use the Control Module - User Interface Module on the American Heat Pump

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 range.

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.

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Note: Picture from americanwaterheater.com

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