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Vertiv / DC power systems

R48-2900U Equipment information & support

The Vertiv R48-2900U is an industrial AC/DC switch-mode rectifier utilizing high-frequency soft-switching topology and active PFC to convert single-phase AC to filtered -48V DC power with autonomous load sharing.

Equipment information

Brand
Vertiv
Equipment model
R48-2900U
Equipment type
DC power systems
Controller / software version
Confirm against the installed equipment
View full product specifications
R48-2900U Official Product View 1

Information below comes from the current product catalogue. Confirm the controller, software version and configuration of the installed equipment separately.

Nominal DC Output Voltage
-48 V DC
AC Input Voltage Range
85 ~ 290 V AC
Physical Dimensions Spec
132 × 85 × 287 mm
Operating Temperature
-40 ~ +75 °C

Alarms & troubleshooting

AC_FAIL (AC Input Abnormal / Mains Loss)
Green LED OFF, Yellow LED Solid ON, Red LED OFF
Utility grid blackout, AC input breaker tripped, or AC voltage outside operating range (<85 VAC or >305 VAC).
1. Use a true-RMS multimeter to measure AC voltage across L and N at the shelf AC breaker or backplane socket (rated 85–300 VAC). 2. Inspect the upstream AC circuit breaker (MCB) or input fuse for tripping or blown status. 3. Reseat the rectifier module firmly to eliminate backplane contact issues; if AC input is normal and contact is solid, replace the module.
DC_HVSD (DC Output Overvoltage Lockout / HVSD)
Red LED Solid ON, Yellow LED OFF, Green LED OFF
Internal PWM loop regulation failure or voltage feedback circuit breakdown, causing output to exceed HW overvoltage threshold (typically 59.5 Vdc ±0.5 Vdc) and triggering latch-off shutdown.
1. Pull the locked rectifier module out of the shelf slot and wait 1 minute until internal bulk capacitors fully discharge (all LEDs completely OFF). 2. Reseat the module and verify initial ramp-up output voltage on the system controller display (NCU/M530S/M830B). 3. If the module triggers the red HVSD lock immediately upon power-up, internal power circuitry is damaged; replace the module immediately.
MOD_OTP (Rectifier Over-Temperature Shutdown / Derating)
Derating: Yellow LED Blinking (0.5Hz), Green LED Solid ON; Shutdown: Yellow LED Solid ON, Red LED Solid ON, Green LED OFF
Ambient temperature exceeding 65°C, cabinet air filters heavily clogged with dust obstructing airflow, or dense dust accumulation on internal heatsinks.
1. Inspect site HVAC/cooling systems to ensure air inlet temperature to the rectifier shelf is within rated limits (<55°C for full power). 2. Clean cabinet dust filters and remove any physical blockage at the front intake and rear exhaust grills. 3. Remove the rectifier module, clear internal heatsink dust using dry compressed air, allow it to cool down, and re-insert to verify automatic recovery.
FAN_FAIL (Cooling Fan Locked-Rotor / Failure)
Red LED Flashing (1Hz) or Solid ON, Yellow LED Solid ON, Green LED ON/OFF
Fan impeller mechanically blocked by foreign objects, fan power/tachometer harness detached, Hall sensor fault, or bearing wear causing RPM below critical threshold.
1. Visually check if the front fan is spinning; use a flashlight to inspect for foreign debris (cable ties, label tape) jamming the impeller. 2. Disconnect AC power to the module and verify that the 4-pin fan internal connector is firmly seated on the control PCB. 3. Manually spin the impeller; if severe friction or mechanical grinding is felt, replace the cooling fan assembly or replace the rectifier module.
CAN_COMM_FAIL (CAN-Bus Communication Failure / Current Share Error)
Yellow LED Blinking (0.5Hz), Green LED Solid ON, Red LED OFF
Bent or oxidized backplane connector signal pins, system controller (SCU/NCU) CAN transceiver malfunction, or CAN address conflict between modules.
1. Access the system controller UI (NCU/M530S) to confirm whether the specific rectifier slot displays Comm Loss / Offline status. 2. Unseat the module and inspect the backplane blind-mate connector with a flashlight for bent, recessed, or oxidized CAN communication pins. 3. Swap the module into a known-good slot; if communication failure persists in the new slot, the internal CAN transceiver is defective; replace the module.

Access Complete Maintenance & Full Alarm Troubleshooting Manual

This page lists high-frequency critical alarm codes commonly encountered in field maintenance. Comprehensive manufacturer troubleshooting matrices, board-level repair guides, detailed electrical schematics, and firmware commissioning manuals are delivered alongside equipment upon formal project procurement, accompanied by dedicated FAE technical support.

Contact Account Manager for Full Manual

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