Can I fix Pentair code ERR HLS myself?

Start with these safe checks: Check flow first: pump running, baskets empty, filter clean, valves open. Let the heater cool and the code clear. Repeated high-limit trips with good flow need a qualified tech. Don't bypass limit switches.

When should I call a technician for code ERR HLS?

Repeated high-limit trips with good flow need a qualified tech. Don't bypass limit switches. Smell gas? Leave right away, don't touch light switches or phones inside, and call your gas utility or 911 from outside. Never open a gas valve, burner, gas line, vent or flue connection, or bypass a safety switch. Repeated lockouts, scorching, soot, or a CO alarm mean shut it off and call a licensed gas technician.

Pentair Pool Heater Error Code ERR HLS / HLS: High limit switch open

What ERR HLS means

The high temperature limit switch opened: water after the first pass through the heat exchanger is over 135°F. It clears when the water drops below 135°F.

Also shown as: HLS, depending on the model.

Likely causes

Low water flow
Dirty filter
Limit switch fault

Safe first checks

Check flow first: pump running, baskets empty, filter clean, valves open.
Let the heater cool and the code clear.

When to stop

Repeated high-limit trips with good flow need a qualified tech. Don't bypass limit switches.

Parts that may help

Only order a part once the checks above point to it, and match the part number to your model.

High Limit / Temp Sensor Kit for Watkins Hot Spring No-Fault Heater$81.99

Checked against: Pentair MasterTemp heater installation and user's guide (Table 8: error and fault codes). Codes can differ by model and year, so confirm with your owner's manual.