Carrier Comfort Network Interface; Charge Refrigerant Into Chiller - Carrier AquaEdge 19MV Start-Up, Operation And Maintenance Instructions Manual

Carrier Comfort Network Interface

The Carrier Comfort Network
is supplied and installed by the electrical contractor. It consists of
shielded, 3-conductor cable with drain wire.
The system elements are connected to the communication bus in a
daisy chain arrangement. The positive pin of each system element
communication connector must be wired to the positive pins of the
system element on either side of it. The negative pins must be
wired to the negative pins. The signal ground pins must be wired
to the signal ground pins. See installation manual.
NOTE: Conductors and drain wire must be 20 AWG (Ameri-
can Wire Gage) minimum stranded, tinned copper. Individual
conductors must be insulated with PVC, PVC/nylon, vinyl,
PTFE (PolyTetraFluoroEthylene), or polyethylene. An alumi-
num/polyester 100% foil shield and an outer jacket of PVC,
PVC/nylon, chrome vinyl, or PTFE with a minimum operating
temperature range of –4°F to 140°F (–20°C to 60°C) is re-
quired. See Table 8 for cables that meet the requirements.
Table 8 — Manufacturers and Cable Numbers
Manufacturer
ALPHA
AMERICAN
BELDEN
COLUMBIA
When connecting the CCN communication bus to a system ele-
ment, a color code system for the entire network is recommend-
ed to simplify installation and checkout. The color code shown
in Table 9 is recommended.
Table 9 — Recommended Color Code
SIGNAL CCN BUS CONDUCTOR
TYPE INSULATION COLOR
+ Red
GROUND Black
– White
WARNING
BE AWARE that certain automatic start arrangements can en-
gage the starter. Open the disconnect ahead of the starter in
addition to shutting off the chiller or pump. Failure to follow
this procedure may result in personal injury by electric shock.
WARNING
The main disconnect on the starter front panel may not
de-energize all internal circuits. Open all internal and remote
disconnects before servicing the starter. Failure to follow this
procedure may result in personal injury by electric shock.

Charge Refrigerant into Chiller

CAUTION
The transfer, addition, or removal of refrigerant in spring
isolated chillers may place severe stress on and damage ex-
ternal piping if springs have not been blocked in both up
and down directions.
(CCN) communication bus wiring
®
Cable No.
2413 or 5643
A22503
8772
02525
CCN TERMINAL
CONNECTION
Red (+)
Black (G)
White (–)
Always operate the condenser and chilled water pumps
during charging operations to prevent freeze-ups.
The standard chiller is shipped with the refrigerant already
charged in the vessels. However, the chiller may be ordered
with a nitrogen holding charge of 15 psig (103 kPa). Evacuate
the nitrogen from the entire chiller, and charge the chiller from
refrigerant cylinders. The full refrigerant charge in the 19MV
chiller will vary with chiller components and design condi-
tions. An approximate charge may be determined by adding the
condenser, evaporator, and economizer charge (as applicable).
Obtain refrigerant charge information from unit nameplate or
from sales documents/E-Cat.
CHILLER EQUALIZATION WITHOUT A PUMPOUT UNIT
When equalizing refrigerant pressure on the 19 series chiller
after service work or during the initial chiller start-up, do not
use the discharge isolation valve to equalize. A charging hose
(connected between the charging valves on top of the cooler
and condenser) should be used as the equalization valve. Fail-
ure to follow this procedure may damage equipment.
The following steps describe how to equalize refrigerant pres-
sure in an isolated chiller without a pumpout unit.
1. Use Quick Test to access cooler and condenser pump control.
IMPORTANT: Turn on the chilled water and condenser
water pumps to prevent freezing.
2. Connect a charging hose between the charging valves on
top of the evaporator and condenser. Slowly open the
refrigerant charging valves. The chiller cooler and con-
denser pressures will gradually equalize. This process
takes approximately 15 minutes.
3. Once the pressures have equalized, the cooler isolation valve
and the condenser isolation valve may now be opened.
TRIMMING REFRIGERANT CHARGE
The 19 Series chiller is shipped with the correct charge for the de-
sign duty of the chiller. Trimming the charge can best be accom-
plished when the design load is available. To trim the charge,
check the temperature difference between the leaving chilled wa-
ter temperature and cooler refrigerant temperature at full load de-
sign conditions. If necessary, add or remove refrigerant to bring
the temperature difference to design conditions or minimum
differential. Obtain refrigerant charge information from unit
nameplate or from sales documents/E-Cat.
22
CAUTION
CAUTION