2.3 IMPORTANT NOTICE
•The supplementary information about the purchased products
is supplied in a CD-ROM, which can be found bundled with
the unit. In case that the CD-ROM is missing or it is not
readable, please contact your Hitachi dealer or distributor.
•PLEASE READ THE MANUAL AND THE FILES ON THE
CD-ROM CAREFULLY BEFORE STARTING TO WORK ON
THE INSTALLATION OF THE AIR TO WATER HEAT PUMP
SYSTEM. Failure to observe the instructions for installation,
use and operation described in this documentation may
result in operating failure including potentially serious faults,
or even the destruction of the air to water heat pump system.
•Verify, in accordance with the manuals which appear in
the unit, that all the information required for the correct
installation of the system is included. If this is not the case,
contact your distributor.
•Hitachi pursues a policy of continuous improvement in
product design and performance. The right is therefore
reserved to vary specications without notice.
•Hitachi cannot anticipate every possible circumstance that
might involve a potential hazard.
•This air to water heat pump has been designed for standard
water heating for human beings only. Do not use this for
other purposes such as for drying clothes, heating foods or
for any other heating process (except swimming pool).
•No part of this manual may be reproduced without written
permission.
•If you have any questions, contact your service contractor of
Hitachi.
•Check and make sure that the explanations of each part of
this manual correspond to your air to water heat pump model.
• Refer to the models codication to conrm the main
characteristics of your system.
•Signal words (NOTE, DANGER and CAUTION) are used
to identify levels of hazard seriousness. Denitions for
identifying hazard levels are provided in initial pages of this
document.
•The operation modes of these units are controlled by the unit
controller.
•This manual should be considered as a permanent part of
the air to water heat pump. It gives a common description
of and information for this air to water heat pump which you
operate as well as for other models.
•Keep the water temperature of the system above the
freezing temperature.
!CAUTION
Donotpasscablesthroughtheventilationhole.
Ventilation
hole
!DANGER
Pressure Vessel and Safety Device: This heat pump is equipped
with a high pressure vessel under PED (Pressure Equipment
Directive). The pressure vessel has been designed and tested
before shipment according to PED.Also, in order to prevent the
systemfromanabnormalpressure,ahighpressureswitch,which
needs no eld adjustment, is utilized in the refrigeration system.
Therefore, this heat pump is protected from abnormal pressures.
However,ifabnormallyhighpressureisappliedtotherefrigeration
cycleincludingthehighpressurevessel(s),itwillresultinserious
injuryordeathduetoexplosionofthepressurevessel.Donotapply
a pressure higher than the following pressure to the system, by
modifyingorchangingthehighpressureswitch.
!CAUTION
Thisunitisdesignedforcommercialandlightindustrialapplication.Ifinstalled
inhouseholdappliance,itcouldcauseelectromagneticinterference.
Start-up and Operation: Checktoensurethatallthestopvalves
arefullyopenedandnoobstacleexistsattheinlet/outletsides
beforestart-upandduringtheoperation.
Maintenance:Periodicallycheckthehighpressuresidepressure.
Ifthepressureishigherthanthemaximumallowablepressure,stop
thesystemandcleantheheatexchangerorremovethecause.
Maximum Allowable Pressure and High Pressure Cut-out
Value:
Refrigerant Maximum Allowable
Pressure (MPa)
High Pressure Switch
Cut-out Value (MPa)
R410A 4.15 4.00 ~ 4.10
?NOTE
ThelabelforthevesselunderPEDareattachedonthehighpressure
vessel.Thepressurevesselcapacityandvesselcategoryareindicated
onthevessel.
Location of High Pressure Switch
Compressor
?NOTE
Thehighpressureswitchisindicatedontheelectricalwiringdiagramin
theoutdoorunitasHPSconnectedtoprintedcircuitboard(PCB1)inthe
outdoorunit.
Structure of High Pressure Switch
Contact Point Pressure Detected
Connected to the electrical wire
!DANGER
• Donotchangethehigh-pressureswitchlocallyorchangethe
highpressurecut-outsetvaluelocally.Ifchanged,itwillcause
seriousinjuryordeathduetoexplosion.
• Donotattempttoturnservicevalverodbeyonditsstop.
SAFETY
PMML0342B rev.6 - 01/2021
2