This block implements the logic for staging the lag pump of a multiple-pump group.
The first staging criterion is optional and is based on ratFlo, the ratio of current flow rate to design flow rate. The lag pump is enabled whenever any of the following is true.
yUp
for 5 min.
have_flowCriterion
is set to true
, the ratio ratFlo
is higher than n / nPum - 0.03 for 10 min, where n is the number
of operating pumps and nPum is the number of pumps operating at design conditions.
The lag pump is disabled whenever any of the following is true.
yDow
for 5 min.
have_flowCriterion
is set to true
, the ratio ratFlo
is higher than (n - 1) / nPum - 0.03 for 10 min.