Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1

7.57. External Centrifugal Purge Control (08.01-P)

Support for the Trane Purifier Purge operation has been added. If Setpoint #163 Purge Target is active, it will

activate this feature.

7.58. MCS Touch Screens Interface (08.00-U)

The interface with the various touch screens has been expanded.

7.59. Sensor Averaging (08.00-R)

Sensor inputs can now be averaged over a period of time, up to a maximum time of 30 seconds. This will

enable sensor smoothing if it is needed. Note: At power up, the initial value of the Sensor Input will be counted

as the sensor history for the number of seconds that has been selected as the averaging time (for example, if

the averaging time was selected at 5 seconds, the initial Sensor Input reading at startup will be counted as

having already run at that value for 5 seconds previously).

7.60. Virtual Points Separated From Real Points (08.00-A)

Virtual points are Sensor Inputs, Relay Outputs, or Analog Outputs that are not connected to an outside

device, while a real point is connected with wiring from the input/output to an outside device (sensor, motor,

etc.). By placing the virtual points after the real points they will not take up points on an actual hardware board.

In the Setup section of MCS-Config the total number of points are specified and the number of Input/Output

boards must now be specified. Only the number of I/O boards indicated will be accessed.

7.61. MDP to EXV Control Logic (8.01-X)

Minimal (oil) Differential Psi (MDP) requires the following Setpoint #205 be active (Refer to section 13 Setpoint

#205).

The EXV logic will forced the state to “EXV MDP CLOSE” when the all of the following conditions are true:

1. Setpoint #205 “MDP MIN OIL DIFF” is active,

2. The compressor oil differential pressure is less than Setpoint #205 value field,

3. The compressor has been running for less than X mins or X is equal to zero (where X is the value

contained in Setpoint #205 “SEC to IGNORE SAFETY” field),

4. The compressor suction pressure is greater than or equal to (Setpoint #77 “LOW SUCTION” value

plus Setpoint #79 “LO SUCT RELD” value).

In this state the EXV will be closed by the adjustment value in Setpoint #205 “Lockout Delay” field. If this value

is positive the valve is closed, if this value is negative the valve will be opened.

The EXV logic will exit the “EXV MDP CLOSE” state and go to “EXV HOLDING” state when the any of the

follow conditions are true:

1. The compressor oil differential pressure is greater than (Setpoint #205 value field plus Setpoint #205

Time field),

2. The compressor has been running for more than X mins and X is not equal to zero (where X is the

value contained in Setpoint #205 “SEC to IGNORE SAFETY” field),

3. The compressor suction pressure is less than or equal to (Setpoint #77 “LOW SUCTION” value plus

Setpoint #78 “LO SUCT ULLD” value).

7.62. Low Discharge Superheat Adjustment to EXV Logic (8.01-X)

Setpoint #110 LOW REFRIGERANT LEVEL TARGET must be active.

If discharge superheat is less than Setpoint #84 LO DISC SUPERHEAT for 1/3 of its safety time and both

discharge temperature and pressure sensors are active, then add the value of Setpoint #110 LOW

REFRIGERANT LEVEL TARGET to Setpoint #9 EXV TARGET. This function takes precedence over the

regular control zone logic.