Riello NXHM - Page 56

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P1
High pressure protection
Heating mode, DHW mode:
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Release the air.
2. Water pressure is lower than 0.1Mpa, charge the water to let the pressure in the
range of 0.15~0.2Mpa.
3. Over charge the refrigerant volume. Recharge the refrigerant in right volume.
4. Electrical expansion valve locked or winding connector is loosen. Tap-tap the valve
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working correctly and install the winding in the right location DHW mode: Water tank
heat exchanger is smaller than the required.
Cooling mode:
1. Heat exchanger cover is not removed. Remove it.
2. Heat exchanger is dirty or something is block on the surface. Clean the heat exchan-
ger or remove the obstruction.
P3
Compressor overcurrent protection
1. The same reason to P1.
2. Power supply voltage of the unit is low, increase the power voltage to the required
range.
P4
Compressor discharge temp. too high
protection
1. The same reason to P1.
2. System is lack of refrigerant volume. Charge the refrigerant in right volume.
3. TW_out temp sensor is loosen Reconnect it.
4. T1 temp sensor is loosen. Reconnect it.
5. T5 temp sensor is loosen. Reconnect it.
P5
Inlet water temp.sensor (Tw_in)
malfunction
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3. Refer to "9.5 Filling water".
4. Make sure there is no air in the system (purge air).
5. Check the water pressure. The water pressure must be >1 bar(water is cold).
6. Check that the pump speed setting is on the highest speed.
7. Make sure that the expansion vessel is not broken.
8. Check that the resistance in the water circuii is not too high for the pump. (refer
to "10.4 The circulation pump").
P6
Inverter module protection
1. Power supply voltage of the unit is low, increase the power voltage to the required
range.
2. The space between the units is too narrow for heat exchange. Increase the space
between the units.
3. Heat exchanger is dirty or something is block on the surface. Clean the heat
exchanger or remove the obstruction.
4. Fan is not running. Fan motor or fan is broken, Change a new fan or fan motor.
5. Over charge the refrigerant volume. Recharge the refrigerant in right volume.
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the air and reselect the pump.
7. Water outlet temp sensor is loosen or broken, reconnect it or change a new one.
8. Water tank heat exchanger is smaller than the required.
9. Module wires or screws are loosen. Reconnect wires and screws. The Thermal
Conductive Adhesive is dry or drop.Add some thermal conductive adhesive.
10. The wire connection is loosen or drop. Reconnect the wire.
11. Drive board is defective, replace a new one.
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defective, replace a new compressor.
Pb
Anti-freeze mode
Unit will return to the normai operation automatically
Pd
High temperature protection of refrige-
rant outlet temp. of condenser
1. Heat exchanger cover is not removed. Remove it.
2. Heat exchanger is dirty or something is block on the surface. Clean the heat exchan-
ger or remove the obstruction.
3. There is no enough space around the unit for heat exchanging.
4. fan motor is broken, replace a new one.
PP
Tw_out - Tw_in unusual protection
1.Check the resistance of the two sensor.
2. Check the two sensors locations.
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5. Four-wayvalve is blocked. Restart the unit again to let the valve change the
direction.
6. Four-wayvalve is broken, change a new valve.