Advanced MxPro 5 Fault Finding: Panel Messages and Diagnostic Steps

The Advanced MxPro 5 is one of the most widely deployed fire alarm panels in UK commercial and industrial installations — and for good reason. It's a capable, well-documented platform with strong loop capacity and good integration options. But fault messages can be dense if you're not familiar with the terminology, and the event log format takes some getting used to.

This guide covers the most common fault conditions you'll encounter, what the panel is telling you, and where to start diagnostically.

Panel Basics Before You Start

Access levels:

• Level 1 — General public (view only)
• Level 2 — Responsible person (evacuate, investigate, silence, reset) — default code 2222
• Level 3 — Engineer (device test, zone isolate, panel config) — default code 3333

Changing the level: The panel cycles through levels using the access key or touchscreen menu. Always confirm you're at the right access level before attempting a reset or isolation.

The event log: Access via Menu → Log → Event Log. The log timestamps every event. Critically, "open" and "close" for a fault means the fault appeared and then cleared — not that it was resolved. An intermittent fault may show dozens of open/close entries if it's rattling on and off.

Loop Device Faults

The MxPro 5 uses the Apollo Protocol (XP95/Discovery) or Hochiki Protocol depending on which loop cards are installed. Fault messages vary slightly between protocols.

Device Fault

A "Device Fault" against a specific loop address means the panel can communicate with the device but the device is reporting an internal fault condition. Common causes:

• Detector contamination — the device has internally flagged that its sensing chamber is dirty. Apollo Discovery detectors will generate a "Device Fault" when their contamination level reaches a threshold. Solution: clean or replace the detector.
• Base fault — a sounder base, isolator base, or relay base has a wiring issue or component fault. Swapping the base (not the detector head) will confirm.
• Device degraded — the device is still functional but operating outside normal parameters (borderline sensitivity, ageing component). Replace.

Device Missing

The panel was previously enrolled with a device at that address, but can no longer communicate with it.

Check:

1. Is the device physically still there? It may have been removed, damaged, or dislodged from its base.
2. Is the base loop wiring intact? A broken connection between that device and the next will cause this device and all downstream devices to show as missing.
3. On Apollo XP95/Discovery loops: open-circuit faults are "soft" — the panel may show only one missing device if the open circuit is isolated between that device and the panel. The device count shown as missing can help you narrow location.
4. On Hochiki protocol loops: a short circuit on a section of loop may cause multiple devices to show missing.

Diagnostic tip: Use the device commissioning screen (engineer level) to manually poll the loop. This shows device responses in real time and helps identify where communication is being lost.

Short Circuit Fault

A short circuit on the loop cable or at a device has been detected. The MxPro 5 uses Short-Circuit Isolation Modules (SCIMs) — on modern installations, a short circuit should be isolated to the section between two SCIMs, limiting the number of devices affected.

If all devices beyond a certain point are missing and you have a short circuit fault, trace the cable from the last responding device to the first non-responding device. The fault is in that section.

Common causes:

• Rodent damage to cable insulation
• A cable stapled through the conductor
• Moisture ingress at a connection point (junction boxes, back boxes)
• A crimped or pinched cable at a door frame or duct entry

Panel Power Faults

Mains Fault

AC supply to the panel PSU has been lost. The panel switches to battery backup.

Check:

1. Is the MCB or fuse supplying the panel open or blown? Many panels are on a 3A or 6A fused spur — check the consumer unit.
2. Has the building had a power outage? If so, the fault will clear when mains is restored.
3. If the supply is present but the panel still shows mains fault: check the internal panel fuse (typically a 1.6A or 2A anti-surge, accessible inside the panel cabinet with the appropriate tools).

Battery Fault / Battery Charger Fault

The standby battery is below threshold or is not charging.

Diagnosis:

• Disconnect the battery leads and measure open-circuit voltage. Below 12.0V indicates a discharged or failed battery.
• If the battery was recently replaced: check the charging current. The MxPro 5 PSU charges at a defined current — if charging shows zero with a known-good battery, the charging circuit may have failed.
• Typical standby battery is 17Ah, 26Ah, or 38Ah (varies with panel size and specified standby duration). The panel's configuration will define the required standby duration — verify the installed battery capacity matches the specification.

PSU Fault

A fault has been detected in the panel power supply unit. This is a hardware fault requiring engineer investigation or PSU replacement. Advanced MxPro PSUs are modular and field-replaceable — check availability from Advanced Electronics or your distributor.

Network and Integration Faults

Network Fault

The MxPro 5 uses Advanced's Hochiki-compatible network (Type C or Type D) for multi-panel configurations. A network fault means one or more panels on the network are not communicating.

Check:

1. Is the affected node panel powered?
2. Is the network cable (RS-485 twisted pair) intact between panels? Check termination resistors are present at the physical ends of the network cable only.
3. Are network card settings correct on the affected panel? Each panel must have a unique node address.

For large networks: The Network Overview screen in engineer mode shows the status of all enrolled nodes. Offline nodes appear grey or with a fault indicator. The panel's network diagnostics screen shows the last known good communication time.

Ancillary Fault

A relay output or interface module has reported a fault. Causes include:

• An interface module (for BMS, door holders, dampers) that has been disconnected or powered down
• A relay output circuit with a short or open condition (if the output is supervised)
• A remote display unit or repeater panel that has lost communication

Identify the specific output or module from the fault message and check its wiring and supply.

Common Event Log Patterns

The event log is the most useful tool for diagnosing intermittent faults. Here's how to read patterns:

Rapid open/close cycles for a single device — usually electromagnetic interference, a loose cable joint, or a device that's about to fail. Replace the device if cleaning doesn't resolve it.

Multiple devices missing simultaneously followed by recovery — power supply issue (momentary power dip causes multiple devices to drop off loop) or a loop wiring issue at a common connection point.

Fault on one device, different device each day — often a contamination issue spreading through a zone (dust or chemicals in the environment), or a panel sensitivity setting that needs adjustment for the environment.

Device fault only in winter / only in summer — temperature-related. Many industrial sites see detector faults caused by condensation in plant rooms in winter. Detector enclosures or anti-condensation heaters may be required.

Day-to-Day Tips

Test mode: Before testing individual devices on site, enter engineer test mode (Level 3 → Test → Device Test). In device test mode, activating a device generates a test event in the log but does not transmit to the ARC or activate outputs. Always exit test mode when finished — it's easy to forget and leave the panel unable to transmit a real alarm.

Isolation log: The MxPro 5 maintains an isolation log. If you find a device or zone is isolated when it shouldn't be, check who isolated it and when. Isolations left from previous service visits are one of the most common "why didn't the alarm work" findings.

Device replacement: When replacing a device on an Apollo loop, the new device must be addressed to the same address as the old one. Most Apollo Discovery devices use DIL switches or software addressing (via the Apollo Device Programmer). Ensure the address matches before installing.

Firmware: Advanced periodically releases firmware updates for the MxPro 5. If you're troubleshooting a complex or repeatable issue that doesn't match any of the above causes, check whether the panel is on a current firmware version — some intermittent issues have been resolved in firmware updates.

Getting More Help

Advanced Electronics provides a comprehensive technical manual for the MxPro 5 (downloadable from their website for registered engineers). Their technical support line is available during business hours and can assist with complex configuration queries, network troubleshooting, and firmware questions. Advanced also offers an online remote diagnostics service for panels connected to their cloud platform.