Multistack MS085XC - Factory Setup and Maintenance; Factory Setup;Commissioning; Pressure Readings and Maintenance Overview; Maintenance Topics

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Factory Setup/Commissioning
Go to the System Variables Menu and select Factory Settings to access the program type and other setup information. Setup is to be done by the Multistack
authorized startup technician. Setup parameters are factory set to default values. Jobsite conditions must be congured at startup. To change these set-
tings requires a password that is available to authorized service technicians by calling Multistack at (608-366-2400).
The Standard Program should be used on applications where no glycol is used in the chilled water side. In this mode the chilled water temperature cutout is
set at 34°F.
The Low Temperature Program should only be used in applications that have a minimum of 25 percent glycol in the chilled water loop. Cutout on low water
temperature in this mode is 20°F and the suction temperature cutout setting (with R-410A refrigerant) is set at 15°F.
Condenser Water Set-Point: If power-actuated buttery valves are used on the condenser side, this value should be set for the desired discharge pressure.
Depending on the condenser water inlet temperature this will adjust the valve to maintain the desired pressure.
Variable Flow: Select ENABLE if doing variable ow on the chilled or condenser side. If not, select DISABLE. To do variable ow, water control valves must
be installed on each module between the water header pipe and heat exchanger.
Bypass: Select ENABLE to leave the valve on the lead module open for minimum ow bypass. Select CHILLED WATER or CONDENSER WATER bypass. If no
valves are installed on the module keep this variable in the DISABLE MODE.
For information on basic control setup of the modules see the Multistack Comput 600 User manual.
Pressure Readings
The operating suction and discharge pressures in the system are directly related to water ow, condenser temperature, chilled water set-point, and system
cleanliness. Standard operating conditions with 95°F leaving condenser water and 45°F leaving chilled water temperature are discharge pressure at 325
psig ( 102°F saturated) and suction pressure at 114 psig (38°F saturated).
All water-cooled modules have a high pressure (HP) cutout safety device and a backup HP cutout switch. The HP cutout is 475 psig for a standard water-
cooled module with R-410A.
Each module also includes a low pressure (LP) safety cutout. The LP cutout is set in the module program at 50 psig.
If circuits are experiencing HP faults rst check to see that the cooling tower fan is operating. Next, verify proper water ow to the brazed plate heat
exchanger and conrm the strainer and lters are clean and free owing.
A LP fault is an indication of low refrigerant charge in the system. If a circuit trips out on a LP fault check the static pressure of the system while the circuit
is in the o mode. If pressures are low, check the circuit for possible leaks. The circuit can be pressurized to 15 psig with refrigerant and topped to 160 psig
with dry Nitrogen.
Maintenance
Use proper safety equiment, tools and procedures when operating and servicing this equipment. Be sure to review all safety warnings, cautions and notes
found on Pg. 3 of this manual.
Preventive Maintenance
Multistack publication MAINT-002-0416 provides heat exchanger preventative maintenance guidelines. Contact your Multistack representative for more
information. Multistack water cooled chillers, especially those with brazed plate heat exchangers, require careful control of the chilled and condensing
water circuits to prevent heat exchanger fouling. Refer to Multistack publication MAINT-001-0416 for water sample collection information.
DANGER: To avoid the risk of electrical shock, personal injury or death, disconnect all electrical power to the unit before performing any maintenance
or service. The unit may have more than one electrical power supply. Assume all electrical wires are live, energized wires. Use lockout/tagouts.