Hitachi YUTAKI Series - Piping Work Connection Considerations; Minimum Water Volume Description

35
Piping work connection considerations
SMGB0066 rev.0 - 12/2009
Water pipe
installation
Service Manual
2
5
1
1
3
4
4
2
3

Pressure gauge

Strainer

Flexiblejoint

Valve

Check valve

caution
Malfunction. Damage by clogging. -
This product is equipped with plate heat exchanger type. In the heat exchanger, water ows through a narrow -
space between the plates. Therefore, there is a possibility that freezing may occur if foreign particles or dust
are clogged. In order to avoid this clogging, mesh water strainer shall be installed in the water inlet pipe and
as close as possible to the plate heat exchanger. In case of punching metal type strainer, mesh hole size shall
be Ø 1.5mm or less.
Never use the salt type antifreeze mixture, since it possesses strong corrosion characteristics, and water -
equipment might be damaged.
When connecting several units to a common pipe, its design should ensure that the water ow on each unit is -
the same (see below gure). Imbalance of water distribution may cause a serious damage like water freezing
in the plate heat exchanger.
Yutaki unit
Indoor
installation
(heating
elements)

Pressure range 0 MPa ~ 1.0 MPa
Water temp. range - 20ºC ~ 90ºC
Pressure range of
water main
0.17~ 0.2 MPa

 

The following problems may occur when the quantity of water in the forced circulation system
(1)
onwatersideisinsufcient.
Compressorinoperationrepeatsnumerous"start/stop"whenlight-loaded,whichmayresultinshorterlifeorfailure. -
Lowtemperatureinwatercirculationduringdefrostoperation,whichmaycauseanalarm(freezeprotection)atthestop -
of the unit.