Jandy Pool Heater CHECK FLOW Error Code

Updated 2026-08-29 · review status: manual-verified Last verified: 2026-08-29

Quick answer

Insufficient Water Flow Water pressure switch has detected insufficient flow through the heater. Pump not running, low pump pressure, dirty filter, pressure switch fault, variable speed pump set too low. Verify pump is running and fully primed. Check filter pressure. Adjust VS pump speed. Inspect pressure switch.

Severity: high · DIY difficulty: intermediate

Safety

TBD - must be written per-code before publish

What CHECK FLOW means

Insufficient Water Flow Water pressure switch has detected insufficient flow through the heater. Pump not running, low pump pressure, dirty filter, pressure switch fault, variable speed pump set too low. Verify pump is running and fully primed. Check filter pressure. Adjust VS pump speed. Inspect pressure switch.

Code meaning varies by series

  • JXi 200/260/400 & LXi 250/400: CHECK FLOW: water pressure switch open - pump not running, low pump pressure, pressure switch fault, or variable speed pump set too low. Auto-clears when adequate flow is restored. (LXi displays this condition as NO FLOW.)

Causes, ranked

  1. 1. Pump is not running. occasional pro-only

    Check:

    Fix:

  2. 2. Low pump pressure. occasional pro-only

    Check:

    Fix:

  3. 3. Pressure switch fault. occasional pro-only

    Check:

    Fix:

  4. 4. Variable speed pump set too low. occasional pro-only

    Check:

    Fix:

Parts & supplies for Jandy Pool Heater: filters, control boards, sensors, and common replacement parts.

HVACDirect →  ·  Amazon →

Commonly searched as: "jandy check flow" · "jandy error code check flow" · "jandy air conditioner check flow"

Sources

  • PoolDial error-code reference (manual-backed) — verified 2026-08-29
  • Jandy JXi Gas-Fired Pool and Spa Heater Installation & Operation Manual (Section 10.2 Service Diagnostic Messages, 10.3 Ignition Control LED Service Codes) — verified 2026-08-29
  • PoolDial Jandy JXi troubleshooting guide (fault-code table) — verified 2026-08-29