Hitachi YUTAKI M RASM-2VRE Instruction Manual page 23

DRAIN PIPING
Additionally, the following elements are required for the DHW
circuit:
Nature Nº
1
Piping connections
2
3
Field supplied
4
5
• 1 Shut-off valve (field supplied): one shut-off valve (4) must
be connected after the DHW outlet connection of the DHW
tank (2) in order to make easier any maintenance work.
• A Security water valve (Field-supplied): this accessory
(3) is a pressure and temperature relief valve that must be
installed as near as possible to the DHW inlet connection of
the DHW tank (1). It should ensure a correct draining (5) for
the discharge valve of this valve. This security water valve
should provide the following:
- Pressure protection
- Non-return function
- Shut-off valve
- Filling
- Draining
?
N O T E
The discharge pipe should always be open to the atmosphere, free of frost
and in continuous slope to the down side in case that water leakage exists.
11 PMML0506 rev.1 - 09/2019
Part name
Water inlet (DHW)
Water outlet (DHW)
Pressure and temperature relief valve
3a Shut-off valve
3b Water check valve
3c Pressure relief valve
Shut-off valve
Draining
9.2.3 Additional hydraulic optional elements
(For DHW)
In case of a recirculation circuit for the DHW circuit:
Nature Nº
1
Piping connections
2
Accessories 3
4
Field supplied
5
1 Recirculation water pump (field supplied): this water
•
pump (3) will help to correctly recirculate the hot water to the
DHW inlet.
1 Water check valve (ATW-WCV-01 accessory): this
•
HITACHI accessory (3) is connected after the recirculation
water pump (4) in order to ensure the non-return of water.
• 2 Shut-down valves (field supplied) (5): one before the
recirculation water pump (4) and other after the water check
valve accessory (3).
9.2.4 Requirements and recommendations for
the hydraulic circuit
• The maximum piping length depends on the maximum
pressure availability in the water outlet pipe. Please check
the pump curves.
• The unit is equipped with a manual air purger (factory
supplied) at the highest location of the unit. If this location
is not the highest of the water installation, air might be
trapped inside the water pipes, which could cause system
malfunction. In that case additional air purgers (field supplied)
should be installed to ensure no air enters the water circuit.
• For heating floor system, the air should be purged by means
of an external pump and an open circuit to avoid air bags.
• When the unit is stopped during shut-off periods and the
ambient temperature is very low, the water inside the pipes
and the circulating pump may freeze, thus damaging the
pipes and the water pump. In these cases, the installer shall
ensure that the water temperature inside the pipes does not
fall below the freezing point. In order to prevent this, the unit
has a self-protection mechanism which should be activated
(refer to the Service manual,
Part name
Water inlet (DHW)
Water outlet (DHW)
Water check valve
(ATW-WCV-01 accessory)
Water pump
Shut-down valve
"Optional functions" chapter).