Hitachi YUTAKI Series - WEH- Water Electric Heater

Water pipe
installation
Service Manual
40
Accessories hydraulic installation
SMGB0066 rev.0 - 12/2009
Remove service cover 1 (item 1) and service cover 2 (item 2). -
Unscrew the nut of the plate heat exchanger assembly (item 3) and the nut of the water pipe 2 assembly (item 6) in -
order to disassemble water pipe1 (item 5) from the Yutaki unit.
Separate the packings (item 4) to make possible to remove the water pipe1 (item 5). -
Put the packings and connect the water pump (item 7) to the Yutaki unit and screw again the nut of the plate heat -
exchanger assembly (item 3) and the nut of the water pipe 2 assembly (item 6).
Connect the pump wiring from the electrical box to the pump according to the detail. -
Assembletheservicecover2(item2)andservicecover1(item1)tonishtheinstallation. -
¡
Additionally,whenthepumpisinstalledoutoftheYutakiunit,theinstallationmustbeinaccordancewiththefollowing
guidelines:
The pump must be installed in an easily accesible place to facilitate inspection and replacement. -
Assemble the pump such that water can not drip into the pump motor or terminal box. -
Carry out stress- free installation with the pump motor shift in horizontal plane (see installation position in the next -
gure):
Themotorterminalboxmustnotpointdownwards(seeadmissibleinstallationpositioninpreviousgure).Itmaybe -
necessary to turn the motor hoosing round after loosening the hexagon socket screws.
 
¡

When Piping connections are performed:
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transmitted.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.
It is recommended to apply ball valves in both water pipe connections to make easier any maintenance work.4.
Properinspectionshouldbeperformedtocheckforleakingpartsinsideandoutsidethesystem,bycompletely5.
opening the hot water inlet and outlet valves to the water condenser.
This WEH must be fully air purged to avoid heating elements radiating the tank case without water. 6.
Install WEH as shows on the following drawing in order to allow a natural purge on the WEH (inlet pipe in the bottom
side,andoutletpipeintheupperside,bothverticallyoriented).
It is recommended to install an air purge after outlet piping in the highest position of the hydraulic installation.
Previous recommendation is a must when there are other parts of hydraulic system that could be installed in a higher
position than WEH.
Applythermalinsulationonthehydraulicsystempipesinordertoavoidaccidentalinjureduetoexcessiveheaton7.
piping surfaces and also to avoid heat losses.
Whentheunitisstoppedduringshutdownperiodsandtheambienttemperatureisverylow,itispossiblethatthe8.
waterinthepipesandinthecirculatingpumpfreeze,thusdamagingthepipesandthewaterpump.