Jandy Pool Heater AUX Monitor Error Code

Updated 2026-09-21 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-09-21

Check your model first

  • JXi 200
  • JXi 260
  • JXi 400
  • LXi 250
  • LXi 400
  • JXi 200/260/400, LXi 250/400

Match the model on your equipment label to the linked manufacturer documentation. The same code can mean different things across model families.

Quick answer

CHECK AUX MONITOR is a Jandy JXi display message, not a numbered fault code. The JXi Installation & Operation Manual (Section 10.2, Service Diagnostic Messages, page 48) lists the message AUX Monitor with a single remedy: Check VersaFlo. VersaFlo is the optional integrated header bypass accessory (Jandy kit JXIVFKIT); the JXi also runs without it, using its internal bypass and thermal regulator valve.

Severity: high · DIY difficulty: easy

Safety

Stop at the exterior: identify whether a VersaFlo bypass (kit JXIVFKIT) is fitted, and check the header area for obvious obstruction or debris. Pool heaters combine gas piping, 240 V wiring, and (on heat pumps) refrigerant - burner, control-board, sensor and sealed-system work requires a licensed technician. If you smell gas, shut the gas valve and leave the area first.

What AUX Monitor means

AUX Monitor is one of the JXi controller's service diagnostic messages. The manual's Service Diagnostic Messages table gives the row as fault message AUX Monitor and remedy Check VersaFlo, and lists no possible cause for this row, so the manufacturer's instruction is a physical check of the VersaFlo bypass rather than a code lookup. VersaFlo is the optional integrated header bypass (kit JXIVFKIT) that lets water bypass the heater when it is not firing; the JXi cabinet wiring diagram carries a bypass motor and bypass switch for that accessory. Owners also report the same condition shown with the FAULT- prefix on the display.

Code meaning varies by series

  • JXi 200/260/400, LXi 250/400: AUX Monitor: check the VersaFlo (header bypass) system. Jandy gives no further owner remedy for this row in the JXi manual.

Causes, ranked

  1. 1. Controller asks for a VersaFlo bypass check (the manufacturer's only listed remedy for this message) common DIY

    Check: Identify whether the heater has a VersaFlo integrated bypass fitted - it is the optional accessory Jandy lists as kit JXIVFKIT in the JXi water-system spare-parts list, mounted at the header. The manual's remedy column for AUX Monitor is only Check VersaFlo, and it lists no possible cause for this row, so confirm the bypass assembly and its motor/switch (shown in the JXi cabinet wiring diagram) are present, seated and unobstructed.

    Fix: If the bypass assembly is intact, clear the message and run a heating cycle to see whether it returns. The JXi manual documents the header bypass reassembly torque pattern (Section 11.1) for anyone who has removed the access cover.

  2. 2. Message repeats after a reset on a heater with no VersaFlo accessory fitted occasional pro only

    Check: A secondary installer reference (PoolDial's Jandy JXi material, checked 2026-09-21) reads this message as an accessory configuration check and states it can be disregarded when no VersaFlo is installed. That wording is not in the Jandy manual, which stops at Check VersaFlo, so treat a repeating message on a heater without VersaFlo as unresolved rather than confirmed benign.

    Fix: Hand the heater to a qualified pool service technician to check the auxiliary monitoring circuit on the control board. Do not open the header, gas train or 240 V wiring yourself.

Related codes

Cross-references for the same fault family, by brand:

Jandy CHECK FLOW · Jandy FAULT-OPEN WATER SENSOR · Raypak WPS Stuck Closed / Water Sw Open

Commonly searched as: "jandy aux monitor" · "jandy error code aux monitor" · "jandy pool heater aux monitor" · "jandy check aux monitor" · "jandy fault check aux monitor" · "jandy check versaflo"

Sources

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