How to Reset a Pentair Pool Heater and Clear Error Codes

Quick Answer

Pentair MasterTemp heaters support three types of resets. A soft reset clears active fault lockouts by pressing ON/OFF, waiting 30 seconds, then pressing ON. A hard reset involves shutting off the gas valve and cutting breaker power for 60 seconds. The SERVICE HEATER interval counter is cleared separately by holding Menu for 5 seconds and navigating to the Service Reset option.

Look, most of the time when someone calls me about a locked-out MasterTemp, it's a power blip or the service counter. A quick reset handles both. But here's the thing: if that fault comes back within 20 minutes of you clearing it, something physical is wrong and you need to stop resetting it. You're just masking a real problem, and honestly, you could be shortening the life of the gas valve doing it.

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How to Reset Your Pentair Poolheater

OK so the MasterTemp doesn't have a big red reset button, which trips up a lot of people. What it does have is a layered reset system: a soft reset through the control pad, a full power-cycle hard reset, and a separate service counter reset buried in the menu. I probably walk someone through this twice a week during pool season. Quick fix when it's a fluke, but if the code keeps coming back, the reset is just buying you time.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Fault lockout requiring manual reset to resume operation40%

Transient fault (power blip, brief low flow) that has self-resolved24%

Post-repair reset after replacing parts22%

SERVICE HEATER maintenance interval counter reached14%

Symptoms You May Notice

Display is stuck on ERR IGN, ERR AFS, E05, or ERR PS and the heater won't fire no matter how many times you hit the ON button
SERVICE HEATER light is on even though you just finished the annual maintenance and everything checks out fine
Heater is completely unresponsive after a power outage, fan's not running, no ignition sounds, just a blank or frozen display
Pool water is dropping in temperature and the heater looks like it's on but there's no burner sound and no warmth coming through the return jets

Tools Required for Diagnosis

Phillips #2 screwdriver (if you need to open the cabinet for internal switch access)Flathead screwdriverFlashlightPhone or pen and paper to photograph the error code before resettingDigital multimeter (if diagnosing further after reset fails)

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

Did the reset not work?

If the problem comes back after following these steps, a component has permanently failed and needs replacement. Check the specific error code your poolheater is showing:

HUB Error →E05 Error →ERR IGN Error →

Frequently Asked Questions

How do I reset a Pentair MasterTemp pool heater?

Most lockouts clear by pressing the ON/OFF button on the control pad, waiting 30 seconds, and turning it back on. If the heater's completely unresponsive, you'll need to find your electrical sub-panel and flip the heater's breaker off for one full minute. This hard reset reboots both the control board and the ignition control module, which is usually what's needed after a power surge or a brief interruption in gas flow. Just make sure you record the error code before you reset anything.

Will resetting my Pentair heater fix the error code?

A reset is a diagnostic step, not a permanent fix. If your heater's got a soot-covered igniter or a scaled-up heat exchanger, the reset will clear the code for maybe a few minutes, but the safety sensors will trip again as soon as the heater gets back up to temperature. If you're resetting the heater every single day just to get the pool warm, you're probably shortening the life of the gas valve and ignoring what might be a genuinely dangerous hardware failure. Two resets and no fix means you've got a real problem.

Is there a reset button on a Pentair pool heater?

There's no physical button labeled Reset on the outside of a MasterTemp. The ON/OFF button handles the logic resets you can do from the pad. But here's something a lot of people don't know: inside the cabinet, there are high-limit switches and a stack flue sensor, and some older versions of those switches have a tiny red button right in the center that has to be physically pressed if they trip from overheating. If those manual switches have tripped, the heater won't start regardless of what you do at the main control pad. You'd need to open the cabinet and look.

How many times can I reset a Pentair pool heater before it needs repair?

Honestly, two times max. If a reset doesn't fix it on the second try, stop trying. Repeatedly resetting a heater that's failing to ignite can let unburned gas accumulate in the combustion chamber, and that's a real safety issue. And if the code is related to high limits or water flow, you could be causing actual damage to the copper fins in the heat exchanger by forcing it to run in an unsafe condition. I'd rather you call me than reset it a fifth time hoping it'll stick.

Why does my Pentair heater keep throwing the same error code right after I reset it?

That's the heater telling you the reset isn't the fix. If the same code comes back within 20-30 minutes, a physical component has failed. ERR IGN coming back fast usually means a bad igniter or a dirty flame sensor. E05 coming right back means your flow switch or pressure switch is tripping for a real reason. ERR AFS coming back means the air flow sensor's reading wrong combustion, which could be a blocked flue or a failed inducer motor. At that point, stop resetting and start diagnosing the specific code.

Related Pentair Poolheater Error Codes

Code: HUBPentair Pool Heater Error Codes Guide Code: E05Pentair Pool Heater E05 Error Code Code: ERR IGNPentair Pool Heater ERR IGN Error

Same Fix on Other Brands

Hayward poolheaterHow to Reset a Hayward Pool Heater

Models Known to Experience RESET Errors

This repair applies to most Pentair poolheaters with this error code. Common model numbers include:

MasterTemp 400 NG (460736), MasterTemp 400 LP (460737), MasterTemp 400 Low NOx NG (461063), MasterTemp 400 Low NOx LP (461064), MasterTemp 300 (460808), MasterTemp 250 (460774), MasterTemp 125 (461057)

Written by

Raj Patel

HVAC & Water Systems Specialist · 15 years experience

Last verified for technical accuracy on March 14, 2026