11
(3) Sequence of Operation
The sequence of operation illustrates time and events that
occur at initial power-up, at startup when auto is selected,
or auto off cycle, or manual stop operation. The time line
sequence of operation follows the events that are
discussed in the following text.
The time line illustration indicates time and corresponding
event. The operator interface displays the time and events
that are referenced in the sequence as they occur.
Familiarization with the sequence helps to understand
when external and internal control devices are cycled on or
off. The time line provides information that may not be
obvious when watching the display. Additionally, this
information can be used for abnormal operation
troubleshooting purposes.
Operational Diagnostics During Machine
Startup.
During the machine start sequence, the chiller relies on
external devices to successfully start and provide correct
feedback. Specifically, the devices and diagnostics include
the chilled water and condenser pump starter, flow switch
confirmation, and ventilator fan operation. The appropriate
message will be displayed on the operator interface as the
start sequence progresses.
The UCP2 waits up to four minutes and fifteen seconds for
proof of chilled water flow, after a water pump start
command output is enabled. Failure to receive chilled
water flow confirmation within the allotted time results in a
message stating “Diagnostics -auto.” This is a MAR-auto
restart diagnostic where the chiller will start once the
chilled water flow switch logic is satisfied.
Failure to receive condenser water flow or ventilator fan
confirmation within the time period’s results in an MMR-
Manual restart diagnostic where the chiller must be reset
before continued operation is allowed.
ABDA Burner Sequence
The burner start sequence is the same for cooling or
heating operating. Always refer to the burner manufacture
literature and the actual sales order which may have
inclusions for special devices. A typical burner sequence of
operation is provided in the burner section of this manual.
The burner has a flame safeguard device that controls the
burner when there is a call for heat from the chiller panel.
The flame safeguard controls burner startup, shutdown,
and monitors burner operation. After confirmation of
combustion, the chiller sets the burner-firing rate via an
analog signal from the burner module. The fire rate signal
is proportional to the energy input as determined by the
chiller control.
To Next Page
Loading...
Need help?
General