Delta RPI Series User Manual (English)

Questions and Answers:

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Jason TurnerSep 3, 2025
What does 'Bus Unbalance' mean on my Delta RPI Inverter?
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  Christine JimenezSep 3, 2025
  A 'Bus Unbalance' error on your Delta Inverter may indicate that the inputs are not totally independent or parallel, so check the inputs connections. It may also be caused by a PV Array short to Ground, so check the PV Array insulation. Another potential cause is a defective or disconnected driver for boost, so check the driver circuit for boost inside the inverter. Finally, a detection circuit malfunction could be the reason; in that case, check the detection circuit inside the inverter.
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Regina WilliamsSep 3, 2025
What does 'Relay Test Open' mean on my Delta Inverter?
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  Douglas HallSep 3, 2025
  A 'Relay Test Open' error on your Delta Inverter can occur if one or more relays are abnormal, so replace the defective relay(s). It may also occur if the driver circuit for the relay malfunction, so check the driver circuit inside the inverter. Also, the detection accuracy might not be correct for Vgrid and Vout, so check the Vgrid and Vout voltage detection accuracy.
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Brittany BridgesSep 2, 2025
What does 'Relay Test Short' mean on my Delta RPI?
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  Mary ThomasSep 3, 2025
  A 'Relay Test Short' error on your Delta Inverter can occur if one or more relays are sticking, so replace the defective relay(s). It may also occur if the driver circuit for the relay malfunction, so check the driver circuit inside the inverter.
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marco50Sep 2, 2025
What does 'RCMU Fail' mean on my Delta RPI?
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  William LewisSep 2, 2025
  A 'RCMU Fail' error on your Delta Inverter may indicate that the RCMU is disconnected, so check the RCMU connection inside the inverter. It may also be due to a detection circuit malfunction, so check the detection circuit inside the inverter.
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Robert PierceSep 2, 2025
What to do if my Delta RPI shows 'HW Connect Fail'?
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  John YoungSep 2, 2025
  If your Delta Inverter displays 'HW Connect Fail', it may be due to a power line being disconnected inside the inverter, so check the power lines inside the inverter. It may also be caused by a defective current feedback circuit, so check the current feedback circuit inside the inverter.
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Lori CamposSep 1, 2025
What does 'HW COMM2' mean on my Delta Inverter?
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  kimberly30Sep 1, 2025
  A 'HW COMM2' error on your Delta Inverter may indicate that the Red. CPU is idling, so check reset and crystal in Red. CPU. It could also mean that the communication connection is disconnected, so check the connection between Red. CPU and DSP.
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Scott BurnsSep 1, 2025
What does 'HW COMM1' mean on my Delta Inverter?
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  stevenvaughnSep 1, 2025
  A 'HW COMM1' error on your Delta Inverter may be caused by DSP idling, so check reset and crystal in DSP. It may also be caused by the communication connection being disconnected, so check the connection between DSP and COMM. Finally, the communication circuit may have malfunctioned, so check the communication circuit.
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Lauren FrederickSep 1, 2025
What does 'HW Efficiency' mean on my Delta Inverter?
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  Matthew AndersonSep 1, 2025
  A 'HW Efficiency' error on your Delta Inverter can be due to incorrect calibration, so check the accuracy of current and power. It may also be caused by a defective current feedback circuit, so check the current feedback circuit inside the inverter.
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Douglas BurkeAug 31, 2025
What does 'HW DSP ADC3' error mean on Delta RPI?
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  brandonwilliamsAug 31, 2025
  A 'HW DSP ADC3' error shown on your Delta Inverter can indicate insufficient input power. Ensure that the input voltage is greater than 150Vdc. It may also be caused by auxiliary power circuitry malfunction, so check the auxiliary circuitry inside the inverter. Finally, a detection circuit malfunction could be the reason; in that case, check the detection circuit inside the inverter.
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Ms. Janet GordonAug 31, 2025
What does 'HW DSP ADC2' error mean on Delta Inverter?
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  Bradley WilliamsAug 31, 2025
  A 'HW DSP ADC2' error appearing on your Delta Inverter could be due to insufficient input power. Ensure the input voltage is above 150Vdc. It may also point to an auxiliary power circuitry malfunction, so check the auxiliary circuitry inside the inverter. Another possibility is a detection circuit malfunction, requiring you to check the detection circuit inside the inverter.

Delta RPI Series Specifications

General

Efficiency	Up to 98.8% (depending on model)
Frequency	50 Hz / 60 Hz
Model	RPI Series
Type	Inverter
Protection Rating	IP65
Cooling	Natural convection
Category	Inverter
Cooling Method	Natural convection
Dimensions	Varies by model
Weight	Varies by model
Protection Features	Overvoltage, Short Circuit