Seresco CWT Series Installation, Operation And Maintenance Manual page 34

– that capacitors are discharged: this shall be done in a safe manner to avoid possibility of sparking;
– that no live electrical components and wiring are exposed while charging, recovering or purging the
system.
– that there is continuity of earth bonding
• If a fault exists that could compromise safety, then no electrical supply shall be connected to the circuit
until it is satisfactorily dealt with.
– If the fault cannot be corrected immediately but it is necessary to continue operation, an adequate
temporary solution shall be used. This shall be reported to the owner of the equipment, so all
parties are advised.
• Where electrical components are being changed, they shall be fit for the purpose and to the correct
specification. At all times the manufacturer's maintenance and service guidelines shall be followed. If in
doubt, consult the manufacturer's technical department for assistance.
Refrigerating Equipment and Piping Check
•
• The following checks shall be applied to installations using FLAMMABLE REFRIGERANTS:
– the actual REFRIGERANT CHARGE is in accordance with the conditioned space and room size within
which the refrigerant containing parts are installed (see table1 and 2)
– the ventilation machinery and outlets are operating adequately and are not obstructed;
– marking to the equipment continues to be visible and legible. Markings and signs that are illegible
shall be corrected;
– refrigerating pipe or components are installed in a position where they are unlikely to be exposed to
any substance which may corrode refrigerant containing components, unless the components are
constructed of materials which are inherently resistant to being corroded or are suitably protected
against being so corroded.
– All field refrigerant joints shall be accessible for inspection prior to being covered or enclosed
Refrigeration Work Tasks
When/if required, service or repair work on refrigeration piping and equipment, that contain A2L (mildly
flammable) refrigerant must be conducted in safe manner, following specific recommendations of respective
Codes and Regulations as well as best field/trade practices.
Pressure/Leak Testing. Leak Detection.
Refrigeration piping circuit must be leak-free to ensure problem-free operation of the equipment, comply with
environmental and safety requirements. Following tasks to ensure that must be performed at different stages of
piping.
After completion of respective work (repair, replacement etc.), the pipework shall be PRESSURE TESTED with an
inert gas and then vacuum tested prior to refrigerant charging.
Pressure-test circuit/equipment – refer to the dehumidifier main label for operating pressure level.
•
o The minimum test pressure for the low side of the system shall be the low side design pressure and the
minimum test pressure for the high side of the system shall be the high side design pressure, unless the
high side of the system, cannot be isolated from the low side of the system in which case the entire
system shall be pressure tested to the low side design pressure.
o Use only dry nitrogen for pressure testing!
o Ensure that dehumidifier valves are in proper position (open/closed – as required by particular task) to
allow for proper propagation of test gas and/or isolate proper segment, if any, of the equipment/piping.
Once circuit successfully charged (after performing all needed steps, like brazing, vacuuming and charging – see
below), all field refrigerant joints indoors shall be TIGHTNESS/LEAK TESTED.
• Test must be performed with device/method with sensitivity of 5 grams per year of refrigerant or better under
a pressure of at least 0,25 times the maximum allowable pressure. No leak shall be detected.
OMM
34
December 2024