Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 315

[ X LED Monitor Display on the Heat Source Unit Board ]
3. Time data storage function
The outdoor (heat source) unit has a simple clock function that enables the unit to calculate the current time with an internal
timer by receiving the time set by the system controller, such as G50.
If an error (including a preliminary error) occurs, the error history data and the error detection time are stored into the ser-
vice memory.
The error detection time stored in the service memory and the current time can be seen on the service LEDs.
Notes:
1) Use the time displayed on the service LED as a reference.
2) The date and the time are set to "00" by default. If a system controller that sets the time for the outdoor (heat
source) unit, such as G50 is not connected, the elapsed time and days since the first power on will be displayed.
If the time set on a system controller is received, the count will start from the set date and the time.
3) The time is not updated while the power of the outdoor (heat source) unit is turned off. When the power is turned
off and then on again, the count will resume from the time before the power was turned off. Thus, the time that
differs the actual time will be displayed. (This also applies when a power failure occurs.)
The system controller, such as G50, adjusts the time once a day. When the system controller is connected, the
time will be automatically updated to the correct current time after the time set by the system controller is re-
ceived. (The data stored into the memory before the set time is received will not be updated.)
(1) Reading the time data:
1) Time display
Example: 12 past 9
* Disappears if the time data is deviated due to a power failure, or if a
system controller that sets the time is not connected.
2) Date display
When the main controller that can set the time is connected
Example: May 10, 2003
When the main controller that can set the time is not connected
Example: 52 days after power was turned on
Alternate display
Alternate display of year and month, and date
* Appears between the year and the month, and nothing appears
when the date is displayed.
Alternate display
* Appears between the year and the month, and nothing
appears when the date is displayed.
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Day count