Daikin Enfinity VFC - Ventilation Air; Cleaning & Flushing Water System

unit installation
IM 930-6 •EnnityVerticalWaterSourceHeatPumps 8 www.DaikinApplied.com
Ventilation Air
Outsideairmayberequiredforventilation.The
temperatureoftheventilationairmustbecontrolledso
thatmixtureofoutsideairandreturnairenteringthe
unitdoesnotexceedapplicationlimits.Itisalsogeneral
practicetocloseofftheventilationairsystemduring
unoccupiedperiods(nightsetback).
Theventilationairsystemisgenerallyaseparate
buildingsubsystemwithdistributionductwork.Toprovide
thoroughmixingoftheoutsideandreturnair,introduce
theoutsideairincloseproximitytothereturnairplenum
inlet.Donotductoutsideairdirectlytotheunitinlet.See
"OperatingLimits"onpage9.
Priortomakingpipingconnections, contractor must clean and
ushwaterloopsystem.Failuretoclean/ushsystemmayresult
innuisancetrippingandprematurecomponentfailure.
CAUTION
Cleaning & Flushing Water System
1. Priortorstoperationofanyunit,thewater
circulatingsystemmustbecleanedandushedof
allconstructiondirtanddebris.
Iftheunitsareequippedwithwatershutoffvalves,
eitherelectricorpressureoperated,thesupplyand
returnrunoutsmustbeconnectedtogetherateach
unitlocation.Thiswillpreventtheintroductionofdirt
intotheunit.SeeFigure7.
Figure 7: Connect the runouts together
Return Runout
SupplyRunout
Mains
FlexibleHose
RunoutsInitially
ConnectedTogether
2. Fillthesystematthecitywatermakeupconnection
withallairventsopen.Afterlling,closeallairvents.
Thecontractorshouldstartmaincirculatorwith
thepressurereducingvalveopen.Checkvents
insequencetobleedoffanytrappedair,ensuring
circulationthroughallcomponentsofthesystem.
Powertotheheatrejectorunitshouldbeoff,andthe
supplementaryheatcontrolsetat80°F(27°C).
Whilecirculatingwater,thecontractorshouldcheck
andrepairanyleaksintheunitandsurroundingpiping.
Drainsatthelowestpoint(s)inthesystemshouldbe
openedforinitialushandblow-down,makingsurecity
waterllvalvesaresettomakeupwateratthesame
rate.Checkthepressuregaugeatpumpsuctionand
manuallyadjustthemakeuptoholdthesamepositive
steadypressurebothbeforeandafteropeningthedrain
valves.Flushshouldcontinueforatleasttwohoursor
longeruntilthedrainwateriscleanandclear.
Unitsmustbecheckedforwaterleaksuponinitialwatersystem
start-up.Waterleaksmaybearesultofmishandlingordamage
duringshipping. Failureby theinstallingcontractortocheckfor
leaksuponstart-upofthewatersystemcouldresultinproperty
damage.
CAUTION
3. Shutoffsupplementalheaterandcirculatorpump
andopenalldrainsandventstocompletelydrain
downthesystem.Shortcircuitedsupplyandreturn
runoutsshouldnowbeconnectedtotheunitsupply
andreturnconnections.Donotusesealersatthe
swivelareconnectionsofhoses.
4. Flushsystemwithwaterfor2hoursorlongeruntil
waterisclean.
5. Rellthesystemwithcleanwater.Testthewater
usinglitmuspaperforacidity,andtreatasrequired
toleavethewaterslightlyalkaline(pH7.5to8.5).
Thespeciedpercentageofantifreezemayalsobe
addedatthistime.Usecommercialgradeantifreeze
designedforHVACsystemsonly.Donotuse
automotivegradeantifreeze.
Oncethesystemhasbeenlledwithcleanwater
andantifreeze(ifused),precautionsshould
betakentoprotectthesystemfromdirtywater
conditions.
Note: Contact a local water treatment company to con-
rm water clarity prior to unit operation.
Dirtywaterwillresultinsystemwidedegradation
ofperformanceandsolidsmayclogsystem-wide
valves,strainers,owregulators,etc.Additionally,the
heatexchangermaybecomecloggedwhichreduces
compressorservicelifeorcausesprematurefailure.
6. Settheloopwatercontrollerheataddsetpoint
to70°F(21°C)andtheheatrejectionsetpointto
85°F(29°C).Supplypowertoallmotorsandstart
thecirculatingpumps.Afterfullowhasbeen
establishedthroughallcomponentsincludingthe
heatrejector(regardlessofseason)andthevented
airandlooptemperatureshavebeenstabilized,
eachoftheunitswillbereadyforcheck,testand
start-up,airbalancing,andwaterbalancing.