SEQUENCE ROTATION EVENTS
A sequence rotation event can be triggered in the
following ways: a periodic interval, a pre-determined
time each day, or a pre-determined time day and time
each week. Please refer to the Quick Setup Manual to
determine how to configure the rotation events.
EQUAL HOURS RUN MODE
The primary function of EHR mode is to keep the
running hours of all compressors in the system as close
as possible. This provides the opportunity to service
all of the compressors at the same time, given that the
expected service interval for the compressors is similar.
EHR is not an energy efficient focused mode of
operation.
Each time the rotation interval elapses, or the rotation
time is reached, the sequence order of compressors is
reviewed and re-arranged dependant on the running
hours recorded for each compressor. The compressor with
the least recorded running hours is assigned as the 'duty'
compressor, the compressor with the greatest recorded
running hours is assigned as the 'last standby' compressor.
For systems with more than two compressors, the
remaining compressor(s) are assigned in accordance with
there recorded running hours in the same way.
Example: The compressors in a four compressor system
have the following recorded running hours when a
rotation event occurs:
•
Compressor 1 = 2200 hours
•
Compressor 2 = 2150 hours
•
Compressor 3 = 2020 hours
•
Compressor 4 = 2180 hours
The new sequence order after the rotation event would
be:
•
Compressor 1 = D
•
Compressor 2 = B
•
Compressor 3 = A
•
Compressor 4 = C
Compressor 3, which has the fewest running hours, will
now be utilized more frequently in the new sequence,
allowing running hours to accumulate at a faster rate.
The X8I continuously monitors the running status of each
compressor and calculates the accumulated running
hours. These readings are viewable and adjustable
in the X8I C01 setting screens. The X8I will use these
values during EHR mode. The running hours on the X8I
should be routinely checked to see that they match the
compressors' local calculations, and adjusted if necessary.
If a compressor is operated independently from
the X8I the running hours record may not be accurately
updated.
The running hours meter display on most
compressors are intended for approximate service
interval indication only and may deviate in accuracy over
a period of time.
Control:
Compressors are utilized, in response to changing
demand, using a 'FILO' (First In, Last Out) strategy. The
'duty' compressor (A) is utilized first followed by (B) if
demand is greater than the output capacity of (A).
As demand increases (C) is utilized followed by (D) if
demand increases further. As demand reduces (D) is the
first compressor to be unloaded, followed by (C) and then
(B) if demand continuous to reduce.
The last compressor to be unloaded, if demand reduces
significantly, is (A). The compressor assigned as (A) in
the sequence is the first to be loaded and the last to be
unloaded.
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