Joe Conen asked a question about data in the City of Westland report (attached):
Q.
Table 1, run times versus volumes - seems like a very high flow rate
discharged. See 8341 Terri. 1 gallon per second? Many others are high
too. Why? Was a bigger pump put it? How is this possible?
A. OHM
responded:
I would cite these reasons and comments for the difference:
§ The Westland project did use a Series 98 (1/2 HP) instead of the
later Series 53 (1/3 HP).
§ The Westland project did not use a line splitter for mounting
the logger, and thus we figured out during it that sometimes the current was
not enough to activate the logging device(that’s why some houses had no
data). There was likely lost time in the logging as it may have been a
matter of split seconds at the start and the end not recorded by the
logger. Another way to evaluate the loggers is by recording number of
events and using a drawdown of each event (usually 6.5 gallons). Total
run time is just another metric, however in the Westland case, it may be
on the conservative side since the logging system was still in a testing phase
and was likely missing some of each event.
§ I think the loggers
likely missed split seconds at the beginning and end of the run cycle as the
current was not high enough yet to activate the logger (a problem we corrected
with the next pilot program by adding a line splitter to amplify the signal
10X). There is also rounding error in that the logger only records to the
half second, potentially losing up to one second each run cycle.
§ I also think that 1
gallon per second is not out of normal. The pump curve for the series 98
with 10 feet of head is 60 gallons per minute. See attached catalog
sheet. My experience also supports that a cycle is about 6 seconds long
to pump 6.5 gallons.
A catalog spec sheet on the Series 98 pump used in Westland is attached.
There are no comments.