Safety Valve - Hitachi YUTAKI Serie Installations- Und Betriebshandbuch

MAINTENANCE

7 Safety valve

• Operation: Check the correct operation of the indoor unit safety valve (pressure relief valve) on the space heating circuit.
Open it manually and some water should be expelled by its connected drain pipe.
8 Air purger:
• Excessive air: Check the correct operation of the indoor unit air purger. Turn it twice at least, since there may be air in the
water circuit, which needs to be expelled by this air purger.
9 Water pump:
• Pump performance curves: Check as explained in point 3 that water flow and pressure is in accordance with the Pump
performance curves.
• Electrical connection: Check the correct connection of the electrical wiring of the water pump. If moisture is detected in the
pump surface, revise the water pipes, since a water leakage could have been occurred.
10 Fixing points tightening:
• Check the fixing points of the indoor unit. Check the indoor unit wall support. The indoor unit has to be always in a vertical
position.
11 Refrigerant piping connection
• Leakage: Check for the refrigerant leakage at the refrigerant piping connections in the indoor unit. Check the different
connections of the plate heat exchanger.
12 Electrical equipment
• Activation: Check for an abnormal activation of the magnetic contactor, the relay, the PCBs and others.
• Line condition: Pay attention to the working voltage, the working amperage and the working phase balance. Check for any
faulty contact that is caused by the loosened terminal connections, the oxidized contacts, the foreign matter and other items.
Check the electrical insulation resistance.
13 Control device and protection device
• Setting: Do not readjust the setting in the field unless the setting is maintained at a point that is different from the point listed
in the Service Manual.
14 Ground wire
• Ground line: Check for the continuity to earth in the main electrical components.
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Descaling (S/SCombi)
Water quality and set temperature can affect the scale production and it can deposit on the surface of the plate heat exchanger,
restricting the heat exchange and the good operation of the unit.
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N O T E
Descaling should be necessary periodically at certain intervals depending on the supplied water quality.
Check the scale level when proceeding maintenance to ensure reliability of the unit.
If necessary, proceed with descaling:
1 Switch OFF the main power supply of the indoor unit.
2 Empty the indoor unit water as explained in "Draining" procedure.
3 Proceed with descaling of the plate heat exchangers.
4 Ensure that the water quality remains compliant with the EU council directive 98/83 EC.
178 PMML0335A rev.1 - 04/2016