Operating instructions
47
During the unit operating life the service checks and tests
must be carried out in accordance with applicable national
regulations.
If there are no similar criteria in local regulations, the
information on checks during operation in annex C of
standard EN 378-2 can be used.
External visual checks: annex A and B of standard EN 378-2.
Corrosion checks: annex D of standard EN 378-2.
These controls must be carried out:
• After an intervention that is likely to affect the resis-
tance or a change in use or change of high-pressure
refrigerant, or after a shut down of more than two years.
Components that do not comply, must be changed.
Test pressures above the respective component design
pressure must not be applied (annex B and D).
• After repair or significant modifications or significant
system or component extension (annex B)
• After re-installation at another site (annexes A, B and
D)
• After repair following a refrigerant leak (annex D).
The frequency of refrigerant leak detection can vary
from once per year for systems with less than 1% leak
rate per year to once a day for systems with a leak
rate of 35% per year or more. The frequency is in
proportion with the leak rate.
NOTE 1: High leak rates are not acceptable. The necessary
steps must be taken to eliminate any leak detected.
NOTE 2: Fixed refrigerant detectors are not designed to
find leaks as they cannot locate the leak.
7.1.1 - Soldering and welding
Component, piping and connection soldering and welding
operations must be carried out using the correct procedures
and by qualified operators. Pressurised containers must not
be subjected to shocks, nor to large temperature variations
during maintenance and repair operations.
7.1.2 - Refrigerant properties
HFC-134a is the standard refrigerant for the 19XR chiller.
At normal atmospheric pressure, HFC-134a will boil at -25°C
and must, therefore, be kept in pressurized containers or
storage tanks. The refrigerant is practically odorless when
mixed with air and is non-combustible at atmospheric
pressure. Read standard EN 378-2 to learn more about
safe handling of this refrigerant.
DANGER: HFC-134a will dissolve oil and some non-
metallic materials, dry the skin, and, in heavy concentra-
tions, may displace enough oxygen to cause asphyxiation.
When handling this refrigerant, protect the hands and
eyes and avoid breathing fumes.
All refrigerant removal and draining operations must be
carried out by a qualified technician and with the correct
material for the unit. Any inappropriate handling can
lead to uncontrolled fluid or pressure leaks.
7.1.3 - Adding refrigerant
Follow the procedures described in chapter 4.10 “Charge
refrigerant into chiller”.
WARNING: Always use the compressor pumpdown func-
tion in the Control Test table to turn on the evaporator
pump and lock out the compressor when transferring
refrigerant. Liquid refrigerant may flash into a gas and
cause possible freeze-up when the chiller pressure is below
207 kPa for HFC-134a. Do not use used refrigerant.
7.1.4 - Removing refrigerant
If the optional pumpout system is used, the 19XR refrige-
rant charge may be transferred to a pumpout storage tank
(see chapter 4.12) or to the chiller condenser or cooler
vessels, if the machine includes isolation valves. Follow the
procedures in the transfer unit installation manual, document
order no. 19999, chapter “Pumpout and refrigerant transfer
procedures”), when removing refrigerant from the storage
tank to a chiller vessel.
A valve under the condenser permits refrigerant removal
during the liquid phase.
7.1.5 - Adjusting the refrigerant charge
If the addition or removal of refrigerant is required for
improved chiller performance, follow the procedures given
in chapter 4.13 “Trimming refrigerant charge”.
7.1.6 - Refrigerant leak testing
Because HFC-134a is above atmospheric pressure at room
temperature, leak testing can be performed with refrigerant
in the chiller. Use an electronic leak detector, soap bubble
solution, or ultrasonic leak detector. Be sure that the room
is well ventilated and free from concentration of refrigerant
to keep false readings to a minimum. Before making any
necessary repairs to a leak, transfer all refrigerant from the
leaking vessel.
Monitoring for and repair of leaks
National regulations isued after the Kyoto protocol and
the European F-gas regulation require monitoring for
leaks and repair of leaks.
Test after service, repair or major leak
If all refrigerant has been lost or if the chiller has been
opened for service, the chiller or the affected vessels must
be pressured and leak tested. Refer to chapter 4.2.2 “Leak
test chiller” to perform a leak test.
WARNING: HFC-134a should not be mixed with air or
oxygen and pressurized for leak testing. In general, this
refrigerant should not be present with high concentrations
of air or oxygen above atmospheric pressures, because the
mixture can undergo combustion.