Low MDC Battery

in HōlHōm Errors and Warnings

Why does HōlHōm+ display the message “LOW MDC BATTERY”?

HōlHōm+ displays the message “LOW MDC BATTERY” when the batteries in the optional Meter Data Collector (MDC) sensor unit are low.  The MDC is the optical sensor attached to your electricity meter that reads your electricity consumption and sends it to your HōlHōm+.  The message displays in full-screen mode, and the backlight flashes on and off until you acknowledge the message. The message then appears in the status line of the home screens until the issue is resolved.


Note The MDC optical sensor is aligned to your meter and caution should be taken to ensure it does not become misaligned, be gentle!


Follow the instructions below, to change the batteries.
  1. The two AA batteries in the MDC are located behind a cover held in place with a slotted screw.  Using a medium sized Slotted or Phillips head screwdriver, turn the screw on the battery cover counter clockwise to open the door. Grease is used to seal the compartment door and it should be left in place.  Note the battery orientation as indicated by icons inside the battery compartment.
  2. Replace the old batteries with new AA size Alkaline or Lithium batteries, close the door and tighten the screw snug.  The batteries will last up to a year.  For best results in cold weather, use Lithium AA size batteries.
  3. After the compartment door is closed the red light will come on solid after about 10 seconds and begin flashing for a minute before turning off.

Note: Your HVAC equipment will continue to run normally when there is a low MDC battery warning.



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