Retrotec USACE - Manual (Page 195)

Appendix D D65
D.4.2.3 Inoperable, Uncalibrated, or Poorly Adjusted Controls
(Ineffi ciency)
Figure D113. Control panel of chiller—uses
sensors in chiller and in connecting piping that
often need calibration.
Many of the chiller controls are internal to the chiller itself, and today’s equip-
ment will typically have a display panel or screen showing performance in-
formation (Figure D113). The rate of energy use, percent load, the internal
pressures and the incoming and outgoing temperatures are some of the chiller
operating data available. This information can be compared to performance
data collected during the commissioning of the system or from the chiller man-
ufacturer to determine whether any dropoff in effi ciency has occurred. There
are control elements external to the chiller that are important to system per-
formance. These include remote temperature and fl ow measurements, valves,
motor speed controls, and decision-making software for chiller operation se-
lection and other operating features of the system. Operating parameters dis-
played by the control system should be checked by visual measurements and
the mode of operation confi rmed by the sequence of operation. If there are
discrepancies in these observations, the control system should be thoroughly
reviewed and recalibrated.
D.4.2.4 Imbalanced Water Flow in System (Ineffi ciency)
Figure D114. Balancing valves of chilled water
system.
Most chillers are connected to a chilled water distribution system that cools a
number of buildings, air-handling units, and the like. All connected equipment