15 fault messages this panel shows on site, each with what it means and the document it's drawn from. [CATALOGUE AUDIT 2026-09-11 — LEGACY: Confirmed real via advancedco.com: "MxPro 4 (Legacy)... no longer available" — superseded by MxPro 5. Genuine discontinued product, not a duplicate or fabrication.]
Auxiliary supply current above expected range
From the panel's own "View - Panel" diagnostic table: Aux Supply is monitored 0mA-500mA; the panel reports Too High when the current exceeds the expected range.
Standby battery voltage above expected range
From the panel's own "View - Panel" diagnostic table: Battery is monitored 0V-30V, normal >25.0V; the panel reports Too High when the reading exceeds the expected range.
Standby battery voltage below expected range
From the panel's own "View - Panel" diagnostic table: Battery is monitored 0V-30V, normal >25.0V under full load. Per the manual's own note, the voltage shown is measured under full load conditions; if it falls below 23.0V under full load test, the panel indicates Too Low.
Charger output voltage above expected range
From the panel's own "View - Panel" diagnostic table: Charger is monitored 0V-30V, normal 27.6V; the panel reports Too High when the reading exceeds the expected range.
Charger output voltage below expected range
From the panel's own "View - Panel" diagnostic table: Charger is monitored 0V-30V, normal 27.6V; the panel reports Too Low when the reading falls below the expected range.
Addressed loop device not responding
Shown against the specific loop address, zone and location text on the display, e.g. "1 004.0 DEVICE MISSING" under the zone's fault list. Indicates the panel is no longer receiving a response from that addressed device.
Earth monitor reading above expected range
From the panel's own "View - Panel" diagnostic table: Earth Monitor is monitored 0V-30V, normal 1.3V; the panel reports Too High when the reading exceeds the expected range. Whether Earth Fault is shown on the display during normal operation is itself a configurable parameter (Section 3.3.15.7, Earth Fault Notification) in the installation and commissioning manual.
Earth monitor reading below expected range
From the panel's own "View - Panel" diagnostic table: Earth Monitor is monitored 0V-30V, normal 1.3V; the panel reports Too Low when the reading falls below the expected range.
Fault in the monitored fire/fault routing transmission path
Applies only when the Routing Interface is set to Monitored (Section 3.3.15.8). Function LED3 (Yellow) indicates a fault in the transmission path of the fire routing connection, and also illuminates if there is a fault on the routing interface or if the routing interface card is not present.
Addressable loop current above expected range
From the panel's own "View - Panel" diagnostic table: each loop's load is monitored 0mA-500mA; the panel reports Too High when the current exceeds the expected range.
Open circuit on an addressable loop
From the panel's own "View - Panel" diagnostic table: each loop's load is monitored 0mA-500mA; the panel reports Open Circuit when the reading falls outside that range in the open direction. Loop Load, V.Out and V.In are shown for each fitted loop driver (2 on the MX-4200, 4 on the MX-4400).
Short circuit on an addressable loop
From the panel's own "View - Panel" diagnostic table: each loop's load is monitored 0mA-500mA; the panel reports Short Circuit when the reading falls outside that range in the short direction.
Sounder circuit load above expected range
From the panel's own "View - Panel" diagnostic table: Sounder A/B Load is monitored 0mA-1000mA; the panel reports Too High when the loop current exceeds the expected range.
Open circuit on a sounder wiring circuit
From the panel's own "View - Panel" diagnostic table: Sounder A/B is monitored 0V-14V, normal 5.5V; the panel reports Open Circuit when the reading falls outside that range in the open direction.
Short circuit on a sounder wiring circuit
From the panel's own "View - Panel" diagnostic table: Sounder A/B is monitored 0V-14V, normal 5.5V; the panel reports Short Circuit when the reading falls outside that range in the short direction.
Records marked “sourced — not yet independently verified” carry a real citation but have not yet completed formal review. Always confirm against the manufacturer's current documentation before acting on site.