Issue with AP8853 PDU - No Phase Meter Readings

[vitokous]

Hi all,

We are experiencing an issue with our AP8853 PDU. The device generated the message:
“Component communications lost with Phase Meter.”

As a result:

• No measurements are being reported to DCE Expert.

• The PDU display shows zero values for all measurements, even though there are multiple loads connected.

• A reset of the management card was performed, but the issue persists.

[JLehr]

Your APC AP8xxx Rack PDU is likely reporting no communication due to a loose wire, a disconnected PDU terminator (especially for metering models), a temporary communication or hardware failure requiring a reboot, or potentially a failing network management card (NMC) or display module.

To troubleshoot, first ensure the PDU is fully powered down, then check for loose wires, verify the terminator is installed, and finally, attempt a power cycle by pressing the reset button or cycling power at the source. 

1. Check the PDU Terminator (for Metering Models - AP84XX, AP86XX) 

Verify Installation:

Metering By Outlet PDUs require a terminator in the IN and OUT ports to function properly.

Install if Missing:

If the terminator is missing or has been removed, install the low profile terminator (part #0W05545A) to resolve communication issues, particularly if you see "No metering outlets detected" or "Lost Communication" errors.

2. Perform a Power Cycle

• Power Off: If you have the ability, fully power cycle the Rack PDU from the power source. 
• Use the Reset Button: Alternatively, press the reset button on the Rack PDU display. 
• Reboot Display: For display-related communication issues, ensure the Rack PDU display connector is reseated, and power cycle the display itself by removing the connector for at least five seconds, as detailed in the APC knowledge base. 

3. Verify Connections 

Check Wiring:

A loose wire is a common cause for the network management card losing communication with the internal monitoring hardware.

Secure the Display Connector:

Check for any visible, loose wire connections on the display module itself.

4. Consider Hardware Failure

Firmware:

While not the most common cause, verify that the Rack PDU firmware is up to date by checking www.apc.com. 

Failing Components:

If the above steps do not resolve the issue, the Rack PDU display module or the entire unit's network management card (NMC) may need to be replaced. Contact APC Support for further assistance.

[JLehr]

Hi @vitokous,

There's a video in this FAQ that might help. https://www.apc.com/us/en/faqs/FA168022/

[vitokous]

Hello,

The issue is that the loads connected to the PDU are critical, and therefore I cannot power down the PDU unless absolutely necessary and no other option is available.

[Teken]

Would it not make sense to schedule this during a maintenance window?!?

Regardless, I haven’t read where you completed any other action items on the list to help narrow down root cause??? 🤦‍♂️

[vitokous]

Hi,

1. The PDUs experiencing this issue are AP8853 and AP8886.

2a. The PDU cannot be powered down (it also cannot be shut down for maintenance, since when one power line is turned off, the other is supplied by a generator, ensuring the installation is never left with only one power source).

2b. A reset has been performed, but the issue persists.

2c. It is not possible to reboot the display due to the inability to power off the PDU.

3a. The wiring has been checked repeatedly, and no problems have been observed.

[Teken]

It’s obvious to me and everyone else this really isn’t a problem. This thread was first created on 09,19, 2025.

Action items were provided to help isolate and identify possible root cause / break fix.

Its currently 10,10, 2025 what have you been doing all this time?!?! 🤦‍♂️

Every serious installation has well defined SOP as it relates to maintenance, hardware replacement, and troubleshooting.

Every site has a maintenance window! How would anything ever get installed, removed, tested if there wasn’t??? 😳

In a real enterprise installation a change order is submitted, reviewed, and approved for next steps of execution.

Meaning everyone in the organization is fully aware of the pending maintenance window!

This allows everyone to plan and schedule other mission critical events for another period so it’s less impactful on the company / end users.

At this juncture you’re literally just wasting time going no where fast! 🤢