Hitachi YUTAKI Series - General Notes

Water pipe
installation
Service Manual
34
General notes
SMGB0066 rev.0 - 12/2009
 
Connectallpipesascloseaspossibletotheunit,sothatdisconnectioncanbeeasilyperformedwhenrequired.1.
Itisrecommendedtouseexiblejointsforthepipingofwaterinletandoutlet,sovibrationwillnotbetransmited.2.
Wheneverpossible,sluicevalvesshouldbeinstalledforwaterpiping,inordertominimiseowresistanceandto3.
maintainsufcientwaterow.
Properleakinspectionshouldbeperformedtocheckforleakingpartsinsideandoutsidethesystem,bycompletely4.
openingthehotwaterinletandoutletvalvestothewatercondenser.Additionally,installequipvalvestotheinletand
outlet piping.
This unit is equipped with an air purge at the highest position of the water system. If this position is not the highest one 5.
withinthewholewaterinstallation,equipanotherairpurge.
Also,equipadraincockontheoutletpiping.Thecockhandleshouldberemovedsothatthecockcannotbeopened
undernormalcircumstances.Ifthiscockisopenedduringoperation,troublewilloccurduetowaterblow-off.
Whennecessary,putinsulationonthepipesinordertoavoidheatlosses.6.
Whentheunitisstoppedduringshutdownperiodsandtheambienttemperatureisverylow,itispossiblethatthewater7.
inthepipesandinthecirculatingpumpfreeze,thusdamagingthepipesandthewaterpump.
Inordertopreventthis,duringshutdownperiodsitisusefultoemptythewaterfromtheinstallation.

note
In that case, open the unit by removing the service cover and unscrew the water inlet thermistor in order to drain -
the water of the circuit (as shown below)
Water inlet
thermistor
Otherwise,itisrecommendedtomaintainthepowersupplytotheinstallation,sinceanelectriccordcouldpreventthe
freezing of the water contained in the circuit.
Additionally,incaseswherewaterdrainageisdifcult,anantifreezemixtureofglycol(ethyleneorpropylene)shouldbe
used (content between 10 % and 40 %).
Theperformanceoftheunitworkingwithglycolmaydecreaseinproportiontothepercentageofglycolused,sincethe
densityofglycolishigherthanthatofwater.(Formoreinformation,seechapter4ofTechnicalCatalogue).