Draining; Heating Coil Circuit; Dhw Circuit - Hitachi YUTAKI S80 Series Installation And Operation Manual

MAINTENANCE

11.3 DRAINING

11.3.1 Heating coil circuit

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Tank over the indoor unit
1 Switch OFF the main power supply of the indoor unit.
2 Close the 2 shut-off valves (field supplied) installed at the
space heating pipes (Water inlet and outlet connections).
3 Open the safety valve of the indoor unit manually. The water
will be expelled by its connected drain pipe and will be driven
to the base hole.
4 There will be a part of the water contained into the indoor unit
which may not be expelled through the safety valve. Open the
cap placed in the lower part of the water pump piping in order
to expel it.
5 Once all the water has been drained, close both safety valve
and cap.
C A U T I O N
Check that drain pipe for safety valve is correctly connected and
placed as far as possible from the indoor unit.
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Tank beside the indoor unit
To drain the tank's heating coil water
1 Switch OFF the main power supply of the indoor unit.
2 Close the recommended 2 shut-off valves (field supplied)
installed between the heating coil pipes (connected to the
tank) and the flexible water pipes of the kit ATW-FWP-01 (con-
nected to the indoor unit safety valve and T-branch).
3 Disconnect the 2 heating coil pipes (connected to the tank)
from the shut-off valves (field supplied) to expel the water con-
tained into the heating coil of the tank.
To drain the indoor unit water
Follow the same procedure explained in
unit, and finally, disconnect the 2 flexible water pipes of the kit
ATW-FWP-01 (connected to the indoor unit safety valve and
T-branch) from the shut-off valves (field supplied) to expel the
remaining water in these pipes.
C A U T I O N
• Take care when draining the water of the tank's heating coil
and the remaining water of the kit ATW-FWP-01 (connected
to the indoor unit safety valve and T-branch). Perform the
draining work as far as possible to the indoor unit.
• The expelled water could be hot and could keep in pressure.
Take care with this draining.
51 PMML0291A rev.2 - 09/2014

11.3.2 DHW circuit

1 Switch OFF the main power supply of the indoor unit.
2 Close the main DHW inlet valve (shut-off valve of the security
3 Close the shut-off valve of the DHW outlet.
4 Open manually the drain valve of the security water valve
5 When the water begins to drain more slowly, disconnect the
6 Continue with the draining process until the tank has been
•
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Tank over the indoor
water valve accessory DHWT-SWG-01) in order to avoid the
tank filling.
accessory DHWT-SWG-01. The water of the tank will expelled
by this drain valve.
DHW outlet pipe from the shut-off valve. By this way, the air
enters to the tank and helps to the draining process.
fully emptied of water.
C A U T I O N
Check that water flows free through the discharge pipe of the
security water valve accessory (pressure relief valve) (DHWT-
SWG-01).
When disconnecting the DHW outlet pipe from the shut-off
valve, the expelled water could be hot and could keep in
pressure. Take care with this draining and perform this work
as far as possible to the tank.
Draining
cap
Safety
valve