Cold Weather Operation; Manual Guide Vane Operation; Refrigeration And Service Log - Carrier AquaEdge 19DV Series Start-Up, Operation And Maintenance Instructions Manual

Cold Weather Operation

When the entering condenser water temperature drops very
low, the operator should automatically cycle the cooling tower
fans off to keep the temperature up and tower bypass piping or
condenser water flow modulation may be required. Economiz-
er bypass option may be required for units operating at low lift
outside of the selected lift as identified in the Carrier Equip-
ment Selection Program.
IMPORTANT: A field-supplied water temperature control
system for condenser water should be installed. The system
should be able to maintain the leaving condenser water tem-
perature at design conditions.

Manual Guide Vane Operation

It is possible to manually operate the guide vanes in order to
check control operation or to control the guide vanes in an
emergency. Manual operation is possible by overriding the tar-
get guide vane position.
NOTE: Manual control overrides the configured pulldown rate
during start-up and permits the guide vanes to open at a faster
rate. Motor current above the electrical demand setting, capacity
overrides, and chilled water temperature below the control point
override the manual target and close the guide vanes. For de-
scriptions of capacity overrides and set points, see the 19DV
with PIC6 Controls Operation and Troubleshooting guide.

Refrigeration and Service Log

A refrigeration log (as shown in Fig. 37), is a convenient checklist
for routine inspection and maintenance and provides a continuous
record of chiller performance. It is also an aid when scheduling
routine maintenance and diagnosing chiller problems.
Keep a record of the chiller pressures, temperatures, and liquid
levels on a sheet similar to the one in Fig. 37. Automatic re-
cording of data is possible by using CCN devices such as the
Data Collection module and a Building Supervisor. Contact a
Carrier representative for more information.
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