Riello NXC 021 - Post-Commissioning Checks

Commissioning
94
EN
• Whenoperatingatmaximumpower(whetherincoolingor
heatingmode)thetemperaturedifferenceofapproxima-
tely
5°Cbetweendeliveryandreturnisrespected.
Upon commissioning the system overall pressure drop is
unknown.Itwillthereforebenecessarytoadjustthewater
ow rate with the control valve until reaching the desired
ratedvalue.
Bycausingthereductionofthewaterpressureinthesystem,
thecontrolvalvealignsthepressure/owcurveofthesystem
withthatofthepump,sothattheratedowratecorrespon
-
dingtothedesiredoperatingpointisreached.Thepressure
dropinthewaterexchanger(readthroughthepressuregau-
ge
placedatexchangerinletandoutlet)isthereferencetobe
usedtocheckandadjusttheratedowrateofthesystem.
Toadjustthecontrolvalve:
• fullyopenthecontrolvalve
• leave the pump running for two hours to eliminate any
solidparticlesinsidethecircuit
• readthepressuredropinthewaterexchangerwhenthe
pumpisturnedonandaftertwohours
• if the pressure drop is decreased, that means that the
shieldinglterisclogged.Itmustberemovedandclea
-
ned.
•
 Repeattheoperationuntilthelteriscompletelyclean.
• Ifthesystempressuredropswellbelowtheavailablestatic
pressure providedbythe pump, the water ow ratewill
belowandthetemperaturedifferencebetweenexchanger
inletandoutletwillbetoohigh.Forthisreasonthepres
-
suredropsmustbeminimised.Checkthatthisdifference
fallswithinthecurvevalues(refertosection"Systemwa-
ter
contentandowrate").
 Eachunitisshippedwiththeexactrefrigerantcharge.
 Should anyof the above-listedcontrols haveproblems:
turnthedeviceoffandcalltheTechnicalServiceimme-
diately.
 Iftheunitisbeingcontrolledthroughdrycontacts:
itisrecommendedtoturnofftheunitwhenalltheter-
minals
 are turned off in order to avoid wasting energy
unnecessarily.
Itisforbiddentooperatethedevicewithaphaseinverted.
4.4 SHUTDOWN FOR EXTENDED PERIODS
Notusingthedeviceforanextendedperiodoftimerequires
usertocarryoutthefollowingoperations:
• deactivatetheunitusingtheon-boardcontrolpanel
• setthesystem'smainswitchtoits"OFF"position,andthe
device'smainswitchtoits"OFF"position
• deactivatetheinternalterminalunitsbysettingeachde
-
vice'sswitchtoits"off"position
• closethewatersystem'sshut-offvalves.
 Thecompressor'selectricheatingelementandtheanti-
freezelogicsaredeactivated.
 Emptythewholesystemoraddsuitableanti-freezeuids
ifthereisariskoffrost.
 Ifthedeviceistobeconnectedinparalleltoaboilerwhi-
le
itisinfunction,makesurethatthetemperatureofthe
watercirculatinginsidethe heatpumpdoes notexceed
60°C.
4.5 TEMPORARY SHUTDOWN
Toshutdowntheunitforperiodsofbriefabsences:
• deactivatetheunitusingtheon-boardcontrolpanelonly
• close the shut-off valves
• opentheby-passvalveforanti-freezeprotection.
Inthismanner,theanti-freezelogicsandthecompressor's
electricheatingelementwillremainenabled.
Ethyleneglycol
percentageinweight
0 12 20 28 35 40 %
Freezing
temperature
0 -5 -10 -15 -20 -25 °C