Operating instructions
41
Controls include an on/off switch, the compressor overloads,
an internal thermostat, a compressor contactor, and a
refrigerant high pressure cutout. The high pressure cutout
is factory set to open at a pressure which depends on the
approval code. Check that the water-cooled condenser has
been connected. Loosen the compressor holddown bolts to
allow free spring travel. Open the compressor suction and
discharge service valves. Check that oil is visible in the
compressor sight glass. Add oil if necessary.
For more details on refrigerant transfer, oil characteristics etc.
see sections 4.11 “Chiller equalization without pumpout
unit” and 4.12 “Chiller equalization with pumpout unit”.
Recalibration of the pressure transducers will be necessary,
because the chiller was initially calibrated at sea level.
CAUTION: The transfer, addition, or removal of refrigerant
in spring isolated chillers may place severe stress on
external piping if springs have not been blocked in both
up and down directions.
The standard 19XR chiller will have the refrigerant already
charged in the vessels. The 19XR may be ordered with a
nitrogen holding charge. Evacuate the entire chiller, and
charge chiller from refrigerant cylinders.
WARNING: When equalizing refrigerant pressure on the
19XR chiller after service work or during the initial chiller
start-up, do not use the discharge isolation valve to equalize.
Either the motor cooling isolation valve or charging hose
(connected between pumpout valves on top of cooler and
condenser) is to be used as the equalization valve.
For safety reasons this valve is supplied locked from the
factory. To manipulate the other valves a special tool
(key type) is required.
Manipulation of the valves must always be done by a
qualified person.
To equalize the pressure differential on a refrigerant isolated
19XL chiller, use the TERMNATE LOCKOUT function of
the Control Test in the SERVICE menu. This will help to
turn on pumps and advise the proper procedure. The follow-
ing procedure describes how to equalize refrigerant pressure
on an isolated 19XR chiller without a pumpout unit:
• Access TERMINATE LOCKOUT function on the
Control Test.
• Turn on the evaporator and condenser water pumps
to prevent freezing.
• Progressively open the refrigerant cooling isolation
valve. The chiller cooler and condenser pressures will
gradually equalize. This process will take approximately
15 minutes.
• Once the pressures have equalized, the cooler isolation
valve, the condenser isolation valve, and the hot gas
isolation valve may now be opened.
WARNING: Whenever turning the discharge isolation
valve, be sure to attach the valve locking device. This will
prevent the valve from opening or closing during service
work or during chiller operation.
The valve is opened counter-clockwise, and closed clockwise.
The following procedure describes how to equalize refrige-
rant pressure on an isolated 19XR chiller using the pump-
out unit:
• Access the TERMINATE LOCKOUT mode in the
Control Test menu of the ICVC.
• Turn on the evaporator and condenser water pumps
to prevent freezing.
• Open valve 4 on the pumpout unit and open valves 1a
and 1b on the chiller cooler and condenser (see Figs. 18
and 19). Progressively open valve 2 on the pumpout
unit to equalize the pressure. This process will take
approximately 15 minutes.
• Once the pressures have equalized, the discharge
isolation valve, cooler isolation valve, optional hot gas
bypass isolation valve, and the refrigerant isolation
valve can be opened. Close valves 1a and 1b, and all
pumpout unit valves.
The full refrigerant charge on the 19XR will vary with
chiller components and design conditions, indicated on the
job data specifications. An approximate charge is given on
the dimensional drawing supplied with the machine.
Always operate the water pumps during charging operations
to prevent freeze-ups. Use the Control Test TERMINATE
LOCKOUT to monitor conditions and start the pumps.
If the chiller has been shipped with a holding charge, the
refrigerant will be added through the refrigerant charging
valve (see item 7 in Figs. 18 and 19) or through the pumpout
charging connection. First evacuate the nitrogen holding
charge from the chiller vessels. Charge the refrigerant as a
gas until the system pressure exceeds 141 kPa for HFC-134a.
After the chiller is beyond this pressure the refrigerant
should be charged as a liquid until all the recommended
refrigerant charge has been added.