After Extended Shutdown; Cold Weather Operation; Manual Guide Vane Operation; Refrigeration Log - Carrier AquaEdge 19XR Series Start-Up, Operation And Maintenance Instructions Manual

If freezing temperatures are likely to occur in the chiller area, drain
the chilled water, condenser water, and the pumpout condenser
water circuits to avoid freeze-up. Keep the waterbox drains open.
It is recommended not to store the refrigerant in the unit if below
freezing temperatures are anticipated. A nitrogen holding charge is
recommended in this case.
Leave the oil charge in the chiller with the oil heater and controls
energized to maintain the minimum oil reservoir temperature.

After Extended Shutdown

Ensure the water system drains are closed. It may be advisable to
flush the water circuits to remove any soft rust that may have
formed. This is a good time to brush the tubes and inspect the
Schrader fittings on the waterside flow devices for fouling, if nec-
essary.
Check the cooler pressure on the HMI panel and compare it to the
original holding charge that was left in the chiller. If (after adjust-
ing for ambient temperature changes) any loss in pressure is indi-
cated, check for refrigerant leaks. See Check Chiller Tightness
section, page 24.
Recharge the chiller by transferring refrigerant from the pumpout
storage tank (if supplied). Follow the Pumpout and Refrigerant
Transfer Procedures section. Observe freeze-up precautions.
Carefully make all regular preliminary and running system
checks. If the compressor oil level appears abnormally high, the
oil may have absorbed refrigerant. Ensure that the oil temperature
is above 40°F (4.4°C) or above the EVAP SAT TEMP plus 50F
(27C).

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. Piping may also be arranged to bypass
the cooling tower.
IMPORTANT: A field-supplied water temperature control
system for condenser water should be installed. The system
should maintain the leaving condenser water temperature at
a temperature that is at least 20F (11C) above the leaving
chilled water temperature.

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 target 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 over-
rides, and chilled water temperature below the control point over-
ride the manual target and close the guide vanes. For descriptions
of capacity overrides and set points, see the 19XR with PIC 6
Controls Operation and Troubleshooting guide.

Refrigeration Log

A refrigeration log (as shown in Fig. 43), 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. 43. Automatic recording
of data is possible by using CCN devices such as the Data Collec-
tion module and a Building Supervisor. Contact a Carrier repre-
sentative for more information.
PUMPOUT AND REFRIGERANT
TRANSFER PROCEDURES

Preparation

The 19XR chiller may come equipped with an optional pumpout
storage tank, pumpout system, or pumpout compressor. The re-
frigerant can be pumped for service work to either the chiller
compressor vessel or chiller condenser vessel by using the op-
tional pumpout system. If a pumpout storage tank is supplied,
the refrigerant can be isolated in the storage tank. The following
procedures describe how to transfer refrigerant from vessel to
vessel and perform chiller evacuation.
The power to the pumpout compressor oil heater must be on
whenever any valve connecting the pumpout compressor to
the chiller or storage tank is open. Leaving the heater off will
result in oil dilution by refrigerant and can lead to compressor
failure.
If the compressor is found with the heater off and a valve open,
the heater must be on for at least 4 hours to drive the refriger-
ant from the oil. When heating the oil the compressor suction
must be open to a vessel to give the refrigerant a means to
leave the compressor.
Always run the chiller cooler and condenser water pumps and
always charge or transfer refrigerant as a gas when the chiller
pressure is less than 35 psig (241 kPa). Below these pressures,
liquid refrigerant flashes into gas, resulting in extremely low
temperatures in the cooler/condenser tubes and possibly caus-
ing tube freeze-up.
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CAUTION
CAUTION