Pentair Error Codes

Find troubleshooting guides for all Pentair error codes.

10 error codes across 1 appliance types

Poolheater

Code	Meaning	Severity
E05	The pressure switch didn't close during the heat cycle, meaning there wasn't enough water flow to flex the internal diaphragm and complete the safety circuit. No pressure signal, no fire. It's the heater protecting itself. high	high
ERR AFS	The combustion air flow switch didn't close during startup, which means either the blower didn't reach adequate speed, or there's a restriction somewhere that's keeping the system from building the negative pressure that switch needs to trip. high	high
ERR IGN	The heater attempted ignition multiple times and failed to establish or hold a flame, triggering a hard lockout. high	high
ERR PS	The ERR PS code fires when the pressure switch on IntelliFlo-integrated and newer digital-display Pentair heaters stays open during a heat call. That open switch tells the control board there isn't enough water flow through the heat exchanger to safely run the burner. high	high
HUB	This is a reference guide covering all Pentair MasterTemp pool heater fault codes and indicators. When the control board sees a reading outside its safety range, it kills the burner and stores a code that tells you exactly which sensor or subsystem triggered the lockout. low	low
NO-POWER	The heater shows no display, no response to controls, or will not begin a heat cycle despite power appearing to be available. moderate	moderate
NOT-HEATING	When these Pentair heaters throw E01, E02, or E05, the control board is detecting bad water flow through the heat exchanger, incorrect temperature readings, or dangerously high exhaust temperatures. All three conditions tell the board to shut the gas valve before something expensive gets damaged. moderate	moderate
RESET	The MasterTemp's control board latches into a fault state when any safety circuit opens, cutting power to the gas valve and halting ignition until someone manually clears it. A reset forces the logic board to flush that fault memory and restart its startup sequence from scratch. The SERVICE HEATER counter is a separate hour-based maintenance timer stored in the board's non-volatile memory. low	low
SERVICE-HEATER	The SERVICE HEATER light means the control board detected either an active hardware fault or the scheduled maintenance timer hit its limit. It's basically a general warning flag that won't tell you anything specific until you get into the diagnostic menu and look at the fault history. moderate	moderate
TROUBLESHOOTING	This covers the six most common failure modes on the Pentair MasterTemp series. When the heater locks out, it's protecting itself from damage. The codes and symptoms point to which system failed: power supply, water flow, gas, ignition, heat transfer, or thermal protection. moderate	moderate