Alarm Code "31 - Hitachi RAS-5HVRNM1E Service Manual

12 Maintenace notes

12.5 Alarm code "31"

Question and answer for the field work
Phenomenon Alarm code "31" sometimes occurred and the system stopped.
The combination of the indoor units and the outdoor unit was the following.
Cause
This system was used in a tenant building. One of tenant's customers turned off the main switch for the indoor unit while
other indoor units are running. This results in a different setting of the total indoor unit capacity in the same refrigerant cycle.
Countermeasure All the main switches for the indoor units were always ON.
462
SMGB0060 rev. 1- 12/2010
Example 4: Alarm code "31"
ON
Power
Source ON OFF ON ON ON