Hitachi YUTAKI Series Instruction And Operation Manual page 191

MAINTENANCE
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Draining
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N O T E
Draining operation is unique for each model. Refer to the service manual of the specific unit for drain operation procedure.
Draining operation for YUTAKI S
YUTAKI S models have no drain port factory supplied. It must be considered the installation of a drain port after the shut-off valve
(factory supplied) and before the water inlet of the unit when proceding to the installation of the unit.
Draining operation for YUTAKI SCombi
Draining of the indoor unit (27)
1 Switch OFF the main power supply of the indoor unit.
2 Close the 2 shut-off valves (factory-supplied) installed at the space
heating connections (Water inlet and outlet connections).
3 Open manually the drain port for indoor unit water (27) and collect
the water into a bucket.
4 Once all the water has been drained, close again the drain port for
indoor unit water.
!
C A U T I O N
When draining the indoor unit water from its drain port, the leaved water could
be hot and could keep in pressure. Perform the draining procedure carefully.
Draining of the DHW circuit (28)
1 Switch OFF the main power supply of the indoor unit.
2 Close the main DHW inlet valve (water inlet shut-off valve) in order
to avoid the tank filling.
3 Close the shut-off valve of the DHW outlet.
4 Connect a drain hose to the drain port for DHW (28) and lead the
other end to the general draining.
5 Open manually the drain port for DHW (28) and wait a long time
until all the water has been removed.
!
C A U T I O N
When draining the DHW from its drain port, the leaved water could be hot and
could keep in pressure. Perform the draining procedure carefully.
Draining operation for YUTAKI S80
To drain the indoor unit follow the next procedure:
1 Switch OFF the main power supply of the indoor unit.
2 Close the 2 shut-off valves (factory-supplied) installed at the space heating connections (Water inlet and outlet connections).
3 Connect a drain pipe to the drain port of the shut-off valves and lead it to the general draining system.
4 Open manually the drain port of the shut-off valves and collect the water into a bucket.
5 Once all the water has been drained, close again the drain port of the shut-off valves and open the main shut-off valve to restart
the normal operation.
!
C A U T I O N
When draining the indoor unit water from its drain port, the leaved water could be hot and could keep in pressure. Perform the draining procedure
carefully.
179 PMML0335A rev.1 - 04/2016