Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1
147
# Name Description
50 CND TRGT
(Modulating Type)
Target the logic will try to maintain by modulating the AO.
LO AMB SUMP OFF
(RO Type)
If active and ambient temperature is less than the value of this Setpoint, then the sump pump
relay will be locked off if it is the starting condenser Relay Output. When the ambient
temperature rises above the value of this Setpoint plus two times the value in Setpoint
#192 “FRZ TEMP DIFF” if active (hardcoded 15°F if inactive), then the sump pump relay
will be allowed on again.
51 CND ADJ DIV
(Modulating Type)
Controls scaling of the amount the AO is adjusted (usually 1). The larger the number the
smaller the AO adjustment as the adjustment will be divided by this value.
CND VFD MIN If there is a VFD associated with the condenser, this is the starting minimum speed.
‘Time (sec)’ field: This field contains the condenser stage that must be on before the VFD is
modulated.
52 CND MIN %
(Modulating Type)
Minimum AO % allowed.
If compressor is off, then check the “Time (SEC)” field:
If 0, then the AO % will be set to the value of this Setpoint. If 2 and the run/stop is set to run,
then set the AO % to 100%, else set the AO % to 0%. This option is selected in the
“Default Valve Opening % when Comp. is OFF” box in the condenser information section
in the MAG HVAC screen.
53 CND ROC
(Modulating Type)
Maximum negative rate of change allowed. If the rate of change is less than this Setpoint,
then stop modulating the AO. The absolute value of this Setpoint also serves as the
maximum positive rate of change allowed. If the rate of change is greater than the
absolute value of this Setpoint, then stop modulating the AO.
54 CND MIN SPD
(RO Type)
Minimum speed percentage for variable speed condenser control.
CND ADJ MULT
(Modulating Type)
Controls scaling of the amount the AO is adjusted. The larger the number the larger the AO
adjustment as the adjustment will be multiplied by this value.
55 CND MAX SPD
(RO Type)
Maximum speed percentage for variable speed condenser control.
CND MIN ADJ
(Modulating Type)
The value in this Setpoint is the minimum % the AO will be modulated when a change is
made.
56 PULSE DELAY Used with variable capacity screws. The number of seconds between load or unload pulses
(Usually between 3 and 5. Allows load change to be checked before next pulse and
eliminates oil foaming when unloading too fast).
‘Time (sec)’ field: If used, this is the fast unloading state time delay. This option is selected in
in the ‘Fast Unload Delay’ box in the ‘Compressor Information’ panel under the MAG V8
screen.
For Fixed Step Compressors with adjustable speed AO’s when returning to 100% after
shutting down another compressor, this Setpoint will be the time frame between capacity
adjustments along with Setpoint #33 “MIN ADJUST %” which is the percent of
adjustment.
57 LO AMB PROC When this Setpoint is active and there is a process pump, the process pump will be turned on
when the ambient temperature is less than the value of this Setpoint. The process pump
will be turned off again when the ambient temperature is 5.0° Fahrenheit greater than the
value of this Setpoint.
58 CFG TESTING This must be setup as ‘Not Used’. If active the system will not lockout when an I/O
communications signal is lost. This Setpoint should NOT be active in a live unit.
59 ACYC OFF->ON This is the anti-cycle time delay (in seconds) from when the compressor was turned off. This
value is used in a calculation to determine how long a compressor should be in the anti-
cycle state. Refer to the Standard Control Options section 7.11, Compressor Anti-Cycle
Logic (OFF to ON).
60 MITSI P-DWN
CUTIN
If the compressor is a Mitsubishi, is being unloaded, and the suction pressure is greater than
this Setpoint, then the compressor will be forced to pump down. NOTE: this value is used
whether the Setpoint is active or inactive.