Can I fix Pentair code ERR AFS myself?

Start with these safe checks: Press HEATER OFF. Check that leaves, debris or nests aren't blocking the heater's air openings, without opening the cabinet. Blower, air switch and combustion checks are gas-appliance work for a qualified tech.

When should I call a technician for code ERR AFS?

Blower, air switch and combustion checks are gas-appliance work for a qualified tech. 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 AFS / AFS: Air flow switch open

What ERR AFS means

The air flow switch is open: the combustion blower isn't running or its air is restricted. If it isn't corrected within 60 seconds, press HEATER OFF.

Also shown as: AFS, depending on the model.

Likely causes

Blower not running
Blocked air intake
Air switch or tubing fault

Safe first checks

Press HEATER OFF. Check that leaves, debris or nests aren't blocking the heater's air openings, without opening the cabinet.

When to stop

Blower, air switch and combustion checks are gas-appliance work for a qualified tech.

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.