Raypak Pool Heater Liming or scale forming in the exchanger Error Code

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

Quick answer

Correct pool water chemistry first. Inspect the bypass for movement and replace if none; replace the U.G. if it doesn't move when heated.

Severity: high · DIY difficulty: intermediate

Safety

TBD - must be written per-code before publish

What Liming or scale forming in the exchanger means

Correct pool water chemistry first. Inspect the bypass for movement and replace if none; replace the U.G. if it doesn't move when heated.

Code meaning varies by series

  • Digital 206A-406A / Low NOx / Professional / Above-Ground: Pool water chemistry out of range (see water chemistry section), bypassing too much water (inspect bypass for movement and replace if none), or U.G. not functioning (replace if no movement when heated).

Causes, ranked

  1. Causes not yet documented — verify against the service manual.

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

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Sources

  • PoolDial error-code reference (manual-backed) — verified 2026-08-29
  • Raypak Digital 206A-406A Installation & Operation Manual (241236), Section 10 Troubleshooting — verified 2026-08-29