In many chilled water systems, bypa

In many chilled water systems, bypass control valves
are installed on the end-use equipment, rather than
throttling valves. Bypass valves control equipment
output by splitting the flow of chilled water, passing
some through the equipment and shunting the rest. As
in the previous case, bypass valves are used to limit
system pressure, or to maintain a minimum flow through
the system pumps, or both. Also, some engineers
believe, incorrectly, that bypass control valves are
necessary for stable control. Figure 4 shows a chilled
water distribution system that uses bypass control valves
on the end-user equipment.