Riello NXC 021 - Maintenance Level 3 Procedures

Maintenance
96
EN
• themodicationoftheparameterssetatthefactory(ap-
plication
changes);
• theremovalordisassemblyoftheHVACunit;
• anyinterventionresultingfromascheduledmaintenance
interventionthatwasnotperformed;
• anyinterventionscoveredbywarranty;
• oneortwoleakchecksperyear,performedbyaqualied
personusingacertiedleakdetector.
Inordertoreducewaste,therefrigerantandtheoilmustbe
compliantwiththecurrentregulations,andtherelativeusa
-
ge
methodsmust limittherefrigerantandloadlosses,and
mustbecarriedoutusingmaterialssuitablefortheproducts.
Anyfaultsandleaksdetectedmustbeimmediatelyrepaired.
Theoil recovered from thecompressorduringmaintenance
activitiescontainsrefrigerant, andmustbehandledaccor-
dingly.
Thepressurizedrefrigerantmustneverbedischargedintothe
open air.
If a cooling circuit is opened, plug all the openings if the
operation isexpected tolast upto onefull day;for longer
periods,llthecircuitwithnitrogen.
Any deviations or failure to observe these maintenance
criteria will nullify the HVAC unit's warranty conditions,
thusabsolvingthemanufacturerofanyresponsibility.
5.2 AIR EXCHANGER
Itisrecommendedtoregularlyinspectthennedcoilsinor-
dertochecktheirlevelofcleanliness.Thisdependsonthe
environmentinwhichtheunitis installed,and thecondi-
tions will be worse in industrial and urban environments,
andarounddeciduoustrees.
Tocleanthennedcoil:
• iftheairheatexchangersareclogged,useabrushtogen
-
tlycleantheminverticaldirection;
• thefanmustbeoffwhenworkingontheairheatexchan-
gers;
•
 the unitshould be shutoff forthis type ofoperation if
deemednecessary,takingintoaccountalltheappropriate
maintenanceconsiderations;
• cleantheairheatexchangersinordertoensuretheunit's
optimaloperation.Thiscleaningoperationisrequiredon
-
cetheairheatexchangersstarttogetdirty;
• thefrequencyofthecleaningoperationsdependsonthe
season andthe unit's location(presence ofwind, dust,
plants,etc.).
 Cleanthennedcoilwithappropriateproducts.
 Neverusepressurizedwaterwithoutalargediffuserat-
tachment.
Neverusehigh-pressuredetergentsforCu/Cu
andCu/Alcoils.
 Concentrated or rotating jets ofwater arestrictly prohi-
bited.
 Never useliquidswith temperatures greater than
45° C to clean theair heat exchangers. 2/3 of corrosion
problemscanbepreventedwithproperandfrequentcle
-
aning(approximatelyeverythreemonths).
5.3 WATER HEAT EXCHANGER MAINTENANCE
Checkthat:
• theinsulatingfoamisintactandremainsrmlyinposi-
tion.
• The BPHEsand the electric pipeheatersare functioning
properlyandarecorrectlypositionedinasecuremanner.
• Theconnectionsonthewatersidearecleananddonot
showanysignsofleaks.
5.4 UNIT MAINTENANCE
 Priortoperforminganyinterventionupontheunit,make
surethatthecircuithasbeenisolatedandthatnoelectri-
cal
voltageispresent.Itshouldbenotedthatthecircuit's
condenserscouldtakeupto5minutestocompletelydi-
scharge
afterthecircuithasbeenisolated.Workuponthe
VFDmustonlybecarriedoutbyqualiedpersonnel.
In the event of an alarm or a persistent problem relating to
the VFD, contact the Technical Service.
VFDs equipped with units do not require an isolation test,
eveniftheyarereplaced;infact,theyaresystematicallyin
-
spected
priortodelivery.Furthermore,thelteringcompo-
nentsinstalledintheVFDcandistortthemeasurementsand
canalsobedamaged.Iftheisolationofthedevice'scompo-
nents
(fanandpumpmotors,cables,etc.)needstobeveri-
ed,theVFDmustbedisconnectedfromthepowercircuit.
5.5 REFRIGERANT VOLUME
Theunitmustbeactivatedincoolingmodeinordertode-
terminewhethertheunitchargeiscorrect,bycheckingthe
actual subcooling.
Asmallrefrigerantleakwithrespecttotheinitialchargewill
beevidentin coolingmode, andwill affect thesubcooling
valueobtainedattheoutputoftheairheatexchanger(ca-
pacitor),butwillnotbevisibleinheatingmode.
It is therefore not possible to optimise the refrigerant
chargeinheatingmodefollowingaleak.Theunitmustbe
activatedincoolingmodeinordertodeterminewhether
anadditionalchargeisrequired.