Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1
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6. Magnum Control States
The Magnum controller is a state computer, that is, decisions are made based upon Setpoints, timers and Sensor
Inputs, the controller moves from one state to another. The controller will change states to ensure the proper
functioning of the chiller package.
As we review the various states, we must remember that a chiller package consists of a number of different parts or
functions: the compressors and their related items such as unloaders hot gas bypasses, etc.; evaporator; and
condensing functions.
Both the Capacity Control States and Compressor Control States are displayed in the Status screens on the Keypad
Display. To view the state of the chiller, select the Status option from the menu on the Keypad. You can then view the
entire status by using the page up / down function keys. The information can also be accessed through MCS-Connect
under status screen by clicking on the CONTROL STATUS button.
6.1. Unit Control States (number)
Note: All User Logic points can now access the Unit Control State. The value accessed is the number listed in
parenthesis in the following headings.
UNIT IN POWER UP (0) 6.1.1.
This state is entered when the Magnum is powered up or the system has been reset. The system will
remain in this state for the time specified in Setpoint #23 “POWER DELAY” or for 60 seconds if not active.
In this state all Relay Outputs are turned off. This time delay is to insure the microprocessor has stable
power before starting the algorithm.
NO RUN- I/O LOST (2) 6.1.2.
This state will be entered whenever the Magnum loses communications with any of the I/O boards that
are connected through the MCS I/O network. When this state is entered the Magnum will generate an
MCS I/O offline alarm, which identifies which I/O is offline and a lost I/O shutdown alarm which locks out
the unit. Once locked out, if there are ten consecutive successful I/O reads the Magnum will reset and
attempt to run. When this occurs a “LOST I/O RESTART” will be generated. Or, the lockout-reset key can
be pressed to reset the Magnum, after the lost I/O has been corrected. This will generate a “LOCKOUT
RESET.” In this state all RO’s except ALARM and OIL HEATER are turned OFF.
UNIT IN LOCKOUT (3) 6.1.3.
This state is entered whenever a critical situation is encountered that could cause harm to the chiller
package. Items such as freeze protect and emergency stop will force the system into this state. Lockouts
can be reset without authorization from the keypad or MCS-Connect program; however if the lockout
condition has not been corrected, the system will again be forced into the LOCKOUT state. In this state,
all RO’s except ALARM and OIL HEATER (for screws with an oil pump) are turned OFF and placed in the
“LOCKOUT” state. Note: If the Lockout Reset is pressed more than the programmed allowable number of
times in one day the unit cannot be reset during the current day except through MCS-Connect and
requires Factory authorization. This number is selected from a drop down menu under the Setup
Information button, with a range of 2 to12.
UNIT IS OFF (4) 6.1.4.
This state is entered when the system has finished a STARTUP, DISABLE, LOCKOUT, or NO RUN- I/O
LOST state. The chiller is now ready to move into an active state to meet the capacity required.
UNIT IS HOLDING (5) 6.1.5.
This state is entered when one of three conditions exists:
1) The control sensor reading is being maintained with in the control zone.