Troubleshooting guide

MAGNUM VERSION 8 MANUAL REVISION 3.1
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7.39. Extra Liquid Line Solenoid Control
Second and third Liquid Line Solenoids (economizers) are
supported and can be used for extra control. To specify, select the
Circuit Base Screen:
The third solenoid (economizer) can be controlled either on the slide
wanted percentage or as the last step on for that compressor (Refer
to section 13 Setpoints #98 and #99). Liquid line solenoids 2 and 3
will be turned on and off as indicated in their Setpoints.
7.40. Outside Air Economizer/Fluid Cooler with Analog
Output Control
The purpose of an economizer/fluid cooler is to take advantage of any available
free cooling so as to avoid the need of mechanical cooling. Several options can
be specified in MCS-Config to accomplish this.
Economizer Set up 7.40.1.
The analog valve that will be modulated is selected in the ‘Economizer AO’ cell
in the Evaporator Information panel. In this example the name is 3 WAY VLV.
If the economizer/fluid cooler has separate fans (not associated with
condensers) then answer yes in the ‘Separate Economizer Fans?’ cell. If Yes,
then four additional cells will appear: ‘Starting Economizer Fan’ (select the first
fan Relay Output), ‘# of Econ Fans’ (specify the number of fan points), ‘Starting
Economizer Fault’ (select the first fan fault, this is a Sensor Input), and ‘# of Econ
Faults’ (specify the number of faults)
In the above example there are two fans and two faults associated with the
economizer/fluid cooler. If there is more than one fan they must be consecutive Relay Outputs. The same
is true of the condenser faults.
The condenser fans can also be used to assist in the free cooling function when the system is not using
mechanical cooling. To set this up in the condenser information grid, select “Fluid Cooler Econo” equals
“Yes”, else “No” if condenser fans are not used. All types of condensers can be used. The above example
has individual fans per compressor. Whenever a compressor is running the control of its condenser fans
will be based solely on the discharge pressure of that compressor, while the condenser fans of
compressors that are not running will be controlled by the economizer function. If the type of condenser is
common; if any compressor is on all of the fans will be controlled by the highest discharge pressure and
not by the economizer function.
The following Setpoints must be set up: #107 ”EcoDelayMech”, #115 “EcoVFDfanDely“, #119
“EcoOffsetON”, #120 “Eco Stg Dely”, #121 “Eco MIN VLV%”, #122 “Eco MAX VLV%”, #123 “Eco MAX
ADJ”, #124 “EcoVlvAdjDly”, #125 “Eco StageDly”, #126 “Eco MULTI”, and #127 “Eco DIVIDE”
(Refer to section 13 for Setpoint descriptions)
Sequence of Operation 7.40.2.
The Economizer logic will be enabled whenever the ambient temperature meets the requirement as stated
in Setpoint #119 “EcoOffsetON” (Ambient Temperature < Target Temperature - Setpoint #119). For