Pentair Pool Heater ERR PS Error Code

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

Quick answer

Water Pressure Switch Insufficient water flow detected before the ignition sequence begins. The pressure switch did not close, preventing the heater from attempting ignition. Pool pump not running, dirty filter causing low flow, closed return valve, undersized pump for heater flow requirement, failed or mis-adjusted pressure switch. Confirm the pump is running with solid prime. Check filter pressu

Severity: high · DIY difficulty: intermediate

Safety

TBD - must be written per-code before publish

What ERR PS means

Water Pressure Switch Insufficient water flow detected before the ignition sequence begins. The pressure switch did not close, preventing the heater from attempting ignition. Pool pump not running, dirty filter causing low flow, closed return valve, undersized pump for heater flow requirement, failed or mis-adjusted pressure switch. Confirm the pump is running with solid prime. Check filter pressure gauge — clean or backwash if elevated. Open all suction and return valves. Verify pump speed is high enough (MasterTemp 125/175: 20+ GPM minimum; 250/400: 40+ GPM minimum).

Causes, ranked

  1. 1. Pump off or insufficient water flow common diy-ok

    Check:

    Fix:

  2. 2. Water pressure switch misadjusted (must close with pump running, open with pump off) common pro-only

    Check:

    Fix:

  3. 3. Blocked pressure tap or bad switch wiring occasional diy-ok

    Check:

    Fix:

Parts & supplies for Pentair 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
  • Pentair MasterTemp/Max-E-Therm Heater Installation & User's Guide (Section 5 Troubleshooting) — verified 2026-08-29