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8.0 Factory Setup/Commissioning Information
By going to the System Variables Menu and selecting Factory Settings you can access the program type as well as other settings. To change these settings you
must enter a password that is available to Authorized Service Technicians by calling Multistack tech support at (608) 366-2400.
The Standard program should be used on applications where no glycol is present in the chilled water loop. In this mode the chilled water temp cut out is 34°F.
The Low Temp program should be used in applications that have a minimum of 25% glycol in the chilled water loop. Cut out on water temp in this mode is
20°F.
The Low Ambient program should be used for applications when the module(s) will be operating below 45°F ambient temperatures, but no glycol is present.
If operating below 45°F and glycol is used on the load side the Low Temp program should be used.
Refrigerant Type: Choose refrigerant type used in the modules. R410a.
Suction Superheat Cut Out: Adjustable from 0-15°F
Variable Flow: Select Enable if doing variable flow on the chilled water side or Disable if not. To do variable flow, 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 flow 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 ASPX Chiller User Manual.
9.0 Daily Log Sheet
On the back page of this manual is an information log sheet for the chiller. The log sheet can be used daily, weekly or as desired to record operation
characteristics of the chiller. The information recorded on the log sheet can also be very helpful for diagnosing potential problems in the system.
10.0 Pressure Readings
The operating suction and discharge pressures in the system are directly related to water flow, condenser temperatures, chilled water set-points, and the
cleanliness of the system. Standard operating conditions at 95°F ambient with 45°F leaving chilled water should be 450 psig (125°F saturated) for discharge
pressure and 114 psig (38° saturated) suction pressure.
All ASPX modules have a high pressure cut out safety device. Each circuit will cut out on HP when the programmed set limit in the master control is met.
Standard setting on this is 585 psig. In addition, a backup HP cut out switch is installed on each module. The standard HP cut switch is set at 585 psig for
R-410A.
Each ASPX module also has a low pressure safety cut out. The LP cut out is controlled by a setting in the program of the module. The LP cut out for modules
with R-410A is 50 psig.
If circuits are faulting on HP faults, you should first check to see that the fans are operating. If both fans are working check the cleanliness of the condenser
coil.
A LP fault is an indication of low refrigerant charge in the system. If a circuit is going out on an LP fault check the static pressure of the system while the circuit
is in the off 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.
