Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1
144
# Name Description
STAGE 15 CUT IN
(Cut In/Out Control)
Stage 15 cut in, Setpoint value contains the voltage when this stage is turned on.
18 LOWSUCPSI DLY Delay in seconds when in ‘Low Suction PSI Opening’ between adjustments to the EXV valve.
STAGE 16 CUT IN
(Cut In/Out Control)
Stage 16 cut in, Setpoint value contains the voltage when this stage is turned on.
19 EXV DELAY Delay in seconds between valve adjustments. Should not be less than 48. (When adjusting at
4x this will allow 12 seconds for the controller to process the results of the last action
before making the next adjustment)
20 EXV STRT TIME This is the time in seconds to hold the valve at the start % Setpoint when the compressor
starts. Since the superheat calculation is not valid when the compressor is not running
the EXV logic sets the valve to a given position for a set time to allow the system to
develop a valid superheat.
‘Time (sec)’ field: If zero, then there is no delay when a compressor is ready to start. If non-
zero, this is the time delay in which the EXV valve is allowed to open before the
compressor starts.
21 MAX TRG RESET This value is used to adjust Setpoint #1 “CTL TARGET”. The Sensor Input value will vary
between 0 and 5 volts and the adjustment to the control target will be modulated from
negative “MAX TRG RESET” to the positive “MAX TRG RESET” value.
22 LOW AMBIENT If the ambient temperature is below this value the system will be disabled and the unit state
will be AMBIENT OFF. The unit will remain off until the ambient temperature rises above
this Setpoint value by 5.0F (2.5C).
23 POWERUP DELAY The time in seconds that the system will remain in the START UP state before moving to the
next state.
24 HI AMBIENT If the ambient temperature is above this value the system will be disabled and the unit state
will be AMBIENT OFF. The unit will remain off until the ambient temperature drops below
this Setpoint value by 5.0F (2.5C).
25 STEP SENSTIY This value is used to adjust the rate of response to changes in the control algorithm. 1 is the
fastest response, whereas higher numbers will mean a more gradual response. Used
only with the Magnum Control Zone control method.
26 STEP DELAY Value: This is the time delay before making adjustments to the system capacity. Used only
with the Magnum Control Zone control method.
‘Time (sec)’ field: If used, this will force a minimum time delay between any two compressor
starts. This time delay is specified in the ‘Minimum Delay Between Compressor Starts’
box in the ‘Compressor Information’ panel under the MAG V8 screen.
27 MAX ROC - Maximum negative Rate of Change allowed before preventing the unit from loading. If the
ROC is less than this value the capacity control state is set to HOLDING. Used only with
the Magnum Control Zone control method.
28 MAX ROC + Maximum positive Rate of Change allowed before preventing the unit from unloading. If the
ROC is greater than this value the capacity control state is set to HOLDING. Used only
with the Magnum Control Zone control method.
29 ROC INTERV Seconds between samples used for calculating the Rate of Change. Used only with the
Magnum Control Zone control method. (Maximum 60 seconds)