Raypak Pool Heater Flue Over Temp / Flue Sense Fail / Blocked Drain Error Code

Updated 2026-08-30 · review status: manual-verified · reviewed by MiniSplitDecoder Editorial Team Last verified: 2026-08-30

Check your model first

  • Professional Series X94
  • Professional Series SR-410
  • X94 / SR-410 (Professional Series Digital)

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

Quick answer

The flue is too hot, its sensor failed, or the condensate-drain switch is closed.

Severity: high · DIY difficulty: easy

Safety

Stop at the exterior: power-cycle at the disconnect, clean the filter/basket, and check for obvious water-flow blockage. Pool heaters combine gas piping, 240 V wiring, and (on heat pumps) refrigerant — burner, control-board, and sealed-system work requires a licensed technician. If you smell gas, shut the gas valve and leave the area first.

What Flue Over Temp / Flue Sense Fail / Blocked Drain means

The flue is too hot, its sensor failed, or the condensate-drain switch is closed.

Code meaning varies by series

  • X94 / SR-410 (Professional Series Digital): Flue Over Temp: heater shut off because flue temperature is too high. Flue Sense Fail: flue monitor enabled and flue temperature sensor open or shorted. Blocked Drain: condensate drain switch is closed.

First checks before service

This page currently documents the safe reset triage. If the code returns, use the linked source manual or a qualified technician for code-specific diagnosis.

  1. 1. One-time fault event (power disturbance or transient sensor reading) common DIY

    Check: Power-cycle at the breaker/disconnect (or unplug for CPAP), restore, and run the system while watching for the code.

    Fix: If the code does not return after a full run cycle, the fault was transient — monitor, no repair needed.

  2. 2. Fault persists after a clean reset occasional pro only

    Check: If the code returns immediately or every session, note the conditions (startup, heating, after rain).

    Fix: A persisting code points at the component the manual assigns to this code — that repair is technician territory.

Commonly searched as: "raypak flue over temp / flue sense fail / blocked drain" · "raypak error code flue over temp / flue sense fail / blocked drain" · "raypak pool heater flue over temp / flue sense fail / blocked drain"

Sources

Related Pool Heater guides

Hayward Pool Heater Error Codes: Safe Checks