McQuay ACZ 045A, Installation, Operation And Maintenance Manual

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IOMM ACZ/AGZ-1 77
Decr.

When changing the value of a menu item entry, pressing “DECR. -” shifts the menu item
display line to the next lower value or previous available selection.
Enter

Once a change has been made to a desired value, pressing “ENTER” locks in the new value.
Clear

Pressing “ALARMS” followed by “CLEAR” clears the current alarm. Also, when a change is
made to a menu item pressing “CLEAR” returns the display to the original value as long as “ENTER”
has not been pressed.
Note:
The cause of an alarm should always be determined and corrected before resetting the
alarm through the keypad.
Example of Keypad Operation -As an example of using the keypad key functions, consider
reprogramming the Leaving Evaporator Set Point from 44°F to 42°F. This consists of changing the
Menu Item 148 (Leaving Evaporator Set Point) entry from “44°F to 42°F”. Assume Menu #I (Unit
Status) is currently in the display. The following key sequence is followed.
1. Press the ”CATEGORY” group ”CONTROL” key one time. This switches the display to Menu
#I13 (the first menu in the “CONTROL” category).
2. Press the “MENU” group “NEXT” key once. This shifts the display to Menu Item 14A (Active
Set Point).
3. Press the “ITEM” group “NEXT’ key once. This shifts the display to Menu Item 14B. (Leaving
Evaporator setpoint).
4. Press the “ACTION” group ‘DEC -” key one time. This prompts the user to enter the password.
“E
NTER
” “E
N T E R
” “E
N T E R
” “E
N T E R
”
5. After the “Password Verified” message, press the “ACTION” group “DEC -” key four times. This
changes the menu item entry to 42°F.
6. Press the “ACTION” group “ENTER” key one time. This stores the new entry into the MicroTech
controller memory.
7. Pressing the “CATEGORY” group “STATUS” key then shifts the display back to Menu #I.
Menu Descriptions
Status Menus
Menus 1 through 12 provide chiller operating information and display of sensor readings. The items
listed under these status menus are affected by the settings under the associated control menus and
are not directly adjusted via the keypad.
Menu #l: Unit Status

The unit operating status is displayed as item 1 within this menu. The second
item is the number of seconds remaining in the unit interstage timer. The third item displays the user
chosen unit operation of chiller or Templifier (heat pump). Option chosen on Menu 23.
Menu #2: Circuit #l Status

The current operating condition of refrigerant circuit #l is displayed
whenever this menu is selected. There is only one item displayed in this menu.
Menu #3 : Circuit #2 Status

The current operating condition of refrigerant circuit #2 is displayed
whenever this menu is selected. There is only one item displayed in this menu.
Menu #4: Water Temperatures

The evaporator leaving water temperature is displayed under item #l
under this menu. Additional items under this menu display the evaporator entering water temperature
as well as the entering and leaving condenser temperatures if these optional sensors have been
installed on the unit.
Menu #5: Circuit #l Pressures

The circuit #l evaporator and condenser refrigerant pressure readings
are displayed under this menu. The calculated minimum and maximum condenser pressure values are
also shown.