Riello NXC 021 - Liquid Refrigerant Charge Handling

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General information
EN
1.2.2 Vibration
Ensureregularlythatthevibrationlevelsremainaccept-
ableandclosetothoseattheinitialunitstart-up.
Nopart ofthe unitmust beusedas awalkway, rackor
support.Periodicallycheckandrepairorifnecessaryre-
placeanycomponentorpipingthatshowsignsofdam-
age. Do not step on refrigeration lines.
Thelinescanbreakundertheweightandreleaserefriger-
ant,causingpersonalinjury.Donotclimbonamachine.
Useaplatform,orstagingtoworkathigherlevels.
Donot introduceanysignicantstaticordynamicpres-
sureintotheheatexchangecircuitwithregardtothede-
signoperatingpressures).
Duringanyhandling,maintenanceandserviceoperations
theengineersworkingontheunitmustbeequippedwith
safetygloves,glasses,shoesandprotectiveclothing.Pay
attentiontoburnswhenbrazing.
Ifanoildrainingorrecoveryoperationbecomesnecessary,
theuidtransfermustbemadeusingmobilecontainers.
Theproductsthatmaybeaddedforthermalinsulationof
thecontainersduringthewaterpipingconnectionproce-
duremustbechemicallyneutralinrelationtothemateri-
alsandcoatingstowhichtheyareapplied.Thisisalsothe
casefortheproductsoriginallysuppliedbyCarrier SCS.
Changetherefrigerantafteranequipmentfailure,follow-
ingaprovidedprocedureorcarryoutarefrigerantanalysis
inaspecialistlaboratory.
1.2.3 Water connections
Make sure there are not water leaks from the system.
Shouldtheunitbeshutdownforalongperiods:
- open the drain valve installed on the hydronic mod-
uleandpartiallydrainthepumpandthewaterpipes
aswellasthedrainvalveontheplate-typeexchanger,
whichmustbeinstalledonthehydrauliccircuit.
- to completely drain the pump, remove the cap on it.
Thisoperationsisessentialiftemperaturesareexpect-
edtodropbelowfreezing.
Iftheunitisnotdrained,themainswitchshouldremain
connected so that the defrost thermostat can operate.
Carefullycleanthesystemwaterlter.
1.2.4 Recommendations
Riellorecommendationsonheatexchangeuids:
• NoNH4+ammoniumionsinthewater,theyareverydetri-
mental for copper. This is one of the most important factors
for the operating life of copper piping. A content of several
tenthsofmg/lwillbadlycorrodethecopperovertime.(the
plateheatexchangerusedfortheseunitshavebrazedcop-
perjoints).
• Cl-Chlorideionsaredetrimentalforcopperwitha riskof
perforationsbycorrosionbypuncture.Ifpossiblekeepbe-
low
10mg/l.
• SO42 sulphate ions can cause perforating corrosion, if their
content is above 30 mg/l.
• Nouorideions(<1,0mg/l)
• NoFe2+andFe3+ionswithnonnegligiblelevelsofdis-
solvedoxygenmustbepresent.Dissolvediron<5mg/lwith
dissolvedoxygen<5mg/l.
• Dissolvedsilicon:siliconis anacidelementofwaterand
can also lead to corrosion risks. Content z1mg/l. wather
hardness:>0,5 mmol/l. Values between 1 and 2,5 can be
recommended. This will facilitate scale deposit that can
limit corrosion of copper. Values that are too high can cause
piping blockage over time. A total alkalimetric titre (TAC)
below100isdesirable.
• Dissolvedoxygen:anysuddenchangeinwateroxygenation
conditionsmustbeavoided.Itisadetrimentaltodeoxy
-
genate
thewaterbymixingitwithinertgasasitistoover-
oxygenateitbymixingitwithpureoxygen.Thedisturbance
of the oxygenation conditions encourages destabilisation
ofcopperhydroxidesandenlargementofparticles.
• Electricconductivity600µS/cm
• pH:idealcasepHneutralat20-25°C–7<pH<8
CAUTION:
Ifthewatercircuitmustbeemptiedforlongerthanone
month,thecompletecircuitmustbeplacedundernitro-
gencharge to avoid any riskof corrosion bydifferential
aeration.
CAUTION:
Periodicallyinspectallvalves,ttingsandpipesofthere-
frigerantandhydroniccircuitstoensurethattheydonot
showanycorrosionoranysignsofleaks;alsooncompo-
nents coating.
CAUTION:
Never use the compressor as a vacuum pump.
CAUTION:
When adjusting the refrigerant charge, always ensure
that water is circulating in the heat exchanger to prevent
any possibility of freezing up. Damage caused by freezing
is not covered by the product warranty.
1.2.5 Liquid refrigerant charge
Checking the charge
CAUTION:
Accidentalexhaustofrefrigerant,whetherduetoasmall
leak or to a large discharge from a piping rupture, can
causefrostbitesandburnstoexposedperson.Neverne-
glect such injures. The installers, owners and especially
therepairersforsmalloutdoorunits,must:
- set a procedure to consult medical experts prior to treat
suchinjuries,
-
providerstaidequipment,especiallyforrapidtreatment
ofeyesinjuries.
WerecommendthemtoapplytheEN378-3Annex3.
Whenadjustingtherefrigerantcharge,alwaysensurethat
wateriscirculatingintheheatexchangertopreventany
possibility of freezing up. Damage caused by freezing is
notcoveredbytheproductwarranty.