Protocol
Control
System
Users
Manual
2/12/01
9. Pump Station
9.1 Overview
The Protocol Refrigeration system offers an optional
water chiller. If a water chiller is used, it will be
equipped with the Hussmann Pump Station Controller.
The Pump Station controller provides control of the
water pump and the fluid cooler (providing low and high
speed fan control and water spray control).
9.2 Hardware
The Hussmann Pump Control System (PCS) uses the
same hardware platform as the Protocol Controller. The
software load is different. The label is different to make
it easy to identify the Pump Station controller from the
Protocol Controller.
9.3 Operation
9.3.1 Pump Motor
There are two motors on a pump station. The pump
motor algorithm will cycle the between the two motors
based on a user entered time interval (the default is 84
hours). The Pump (Relay 8) output will be used to
switch the pumps. When the output is deenergized,
pump #1 will be switched on. When the output is
energized, pump #2 will be switched on.
The pump motors are monitored by the corresponding
proof inputs. If a pump motor is on, the corresponding
proof input should be active (contact closed). If the
proof input does not close within 5 seconds of switching
the pump motor on, the controller will switch to the other
pump and signal a proof alarm. The controller will stop
the timer until the user resets the proof failure by
entering the maintenance screen and reseting the proof
alarm. At this point the timer will start over at 0 and
normal operation will continue.
The controller will monitor the water pressure to insure
proper pressure at all times. If the water pressure is
outside of the low and high pressure setpoints for a
programmable amount of time, an alarm will be
indicated and the controller will be switched to the other
pump. The interval timer will not operate until the
condition is reset by the user.
9.3.2 Fluid Cooler
The fluid cooler algorithm attempts to maintain the
temperature of the glycol leaving the fluid cooler. This
is done by cycling on the spray water and low/high speed
fans. The control is a simple cut in/cut out algorithm.
The controller monitors the temperature of the glycol
leaving the fluid cooler and turns on the appropriate
outputs based on the cut in and cut out values for each.
Note that there will be a cut in and cut out parameter for
each output. When the glycol temperature is above the
cut in temperature for the each output, that output will be
turned energized. When the temperature goes below the
cut out temperature, the output will be deenergized.
Note that the outputs are independent and are controlled
only by the corresponding cut in/cut out parameters.
If a proof failure occurs for an output, an alarm will be
signaled. Other than signaling an alarm, the controller
will operate normally.
A mode will be provided that allows for winter operation
or low ambient conditions to lockout the Spray water
pump. A cut in and cut out setpoint will be provided that
locks out the water pump based on the ambient
temperature. If the ambient temperature is below the cut
in, the water pump output will be locked out and will not
be energized. If the temperature comes above the cut
out, the water pump output will be energized based on
the spray water cut in/cut out setpoints. There will also
be a glycol override temperature setpoint. When the
glycol temperature is above this setpoint the spray water
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