Brands & error codes
Pentair pool error codes
These meanings come from Pentair's own manuals for the MasterTemp heater, the IntelliFlo3 VSF pump and the IntelliChlor salt system. Older models can show different messages, so check your manual.
MasterTemp heater
| Code | What it means |
|---|---|
| ERR PS | Water pressure switch open: no water flow through the heater. Clears when flow is established. |
| ERR HLS | High temperature limit switch open: water after the first pass through the heat exchanger is over 135°F. Clears when it drops below 135°F. |
| ERR AFS | Air flow switch open: the blower isn't on or its air is restricted. If not corrected within 60 seconds, press HEATER OFF. |
| ERR IGN | The ignition control module couldn't light the heater. Press HEATER OFF to clear. |
| ERR AGS | Automatic gas shutoff: water after the second pass is over 140°F. Buttons disabled; reset by cycling power. |
| ERR SFS | Stack flue temperature over 480°F. Buttons disabled; reset by cycling power. |
| E05 / E06 | Stack flue sensor open (E05) or shorted (E06). |
| E01 / 126 | Water temperature sensor open (E01) or shorted (126). |
Older MasterTemp panels use SERVICE SYSTEM and SERVICE HEATER lights instead. Pentair says that if the light stays on after the filter has been serviced, have a qualified tech check the pressure switch.
IntelliFlo3 VSF pump
When an alarm triggers, the ON/STOP light blinks red and the pump stops until it's resolved. A warning blinks green/yellow.
| Alarm / warning | What it means |
|---|---|
| Priming Failure | Often not enough water in the strainer pot. See pump not priming. |
| Overheat | High internal temperature, from a blocked cooling fan or very hot air. The pump slows down to cool off. |
| Over Current | More load on the motor: debris, part interference, age or supply voltage. |
| Over / Under Voltage | Supply voltage out of range. Clears when voltage returns to normal. |
| Speed / Pressure / Flow Limit | The pump hit a programmed limit trying to reach the target. |
| Internal Fault | Drive hardware or software error. Disconnect power for a minute; if it stays, call a pool pro. |
| Offline | The Pentair cloud can't reach the pump: power or Wi-Fi. |
IntelliChlor salt system
Salt, Cell, Flow and Cold Water lights tell you why it isn't making chlorine. See salt cell codes for the full table.
What you can safely do
- For ERR PS, priming and flow lights: check the water level, baskets, filter, valves and pump speed.
- For HLS or AGS: confirm full flow, then let it cool. Repeated trips need a tech.
- For IGN, AFS, SFS and sensor codes: these involve gas, combustion or electrical parts. Call a qualified tech.
Common questions
What does ERR PS mean on a Pentair heater?
The water pressure switch is open because there isn't enough water flow through the heater. Check the pump, filter, baskets and valves. Pentair says the error clears once flow is established.
What does ERR AGS mean on a MasterTemp?
Automatic gas shutoff: water leaving the second pass of the heat exchanger went above 140°F. The buttons are disabled and you reset it by cycling power. Check flow first, and call a tech if it repeats.
Why is my IntelliFlo3 blinking red?
A blinking red ON/STOP light means an alarm, and the pump stops until it's resolved. The alarm name shows in the Pentair Pool app, your automation or the optional touchscreen.
Related guides
Heater won't fire
No heat, a flow or pressure code, or an ignition lockout. Flow comes first.
Read the guideVariable-speed pump codes
Priming, overheat, overcurrent and voltage alarms across the big three brands.
Read the guideSalt cell / chlorinator codes
No Flow, Check Salt, Inspect Cell and what the IntelliChlor LEDs mean.
Read the guidePump not priming
Pump runs but the basket won't fill. Almost always air or water level.
Read the guideSources
- Pentair, MasterTemp pool and spa heater installation and user's guide: safety controls and Table 8, heater error and fault codes
- Pentair, IntelliFlo3 VSF / IntelliPro3 VSF installation and maintenance guide: priming, drive LEDs, troubleshooting chart, alarms and warnings
- Pentair, IntelliChlor salt chlorine generator (IC15/IC20/IC40/IC60) installation and user's guide: salt, cell, flow and cold-water LEDs
Brand names belong to their owners. Pool Helpline isn't affiliated with or endorsed by any manufacturer. Steps and codes vary by model and year, so always check your own owner's manual.
