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Pentair Pool Heater ERR IGN Error: Ignition Failure Fix

Quick Answer

Pentair ERR IGN means the MasterTemp attempted ignition and either the igniter did not glow hot enough, the flame sensor did not detect a flame within the trial period, or gas did not reach the burner. A dirty flame sensor rod is the single most fixable cause and should be cleaned first. Gas supply issues account for 30% of cases.

Pentair ERR IGN means the MasterTemp attempted ignition and either the igniter did not glow hot enough, the flame sensor did not detect a flame within the trial period, or gas did not reach the burner. A dirty flame sensor rod is the single most fixable cause and should be cleaned first. Gas supply issues account for 30% of cases. The gas valve receives a 24VAC signal during ignition - confirm this before replacing the valve.

PentairPoolheaterSeverity: highDifficulty: intermediate76% DIY Success
Time to Fix
30–150 min
Difficulty
intermediate
Parts Cost
$15 – $350
Tools Needed
Multimeter, Fine steel wool
Wrong code?

Not seeing ERR IGN on your display?

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ignition failure lockout
HaywardIF
ignition failure lockout
Hayward10

What Does the ERR IGN Code Mean?

ERR IGN is a hard ignition lockout after multiple failed ignition attempts - check gas supply and clean the flame sensor before replacing parts.

Most Likely Causes

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

Carbon-coated or corroded flame sensor rod not sensing flame40%
Gas supply valve off, low gas pressure, or meter in lockout24%
Worn or cracked hot surface igniter not reaching ignition temperature14%
Insect nest or debris blocking gas orifice12%
Gas valve not opening due to failed coil or wiring issue10%

Symptoms You May Notice

  • ERR IGN displayed after 3 ignition attempts
  • You can hear the blower start and igniter click but no ignition
  • Heater sparks but no flame establishes
  • Heater was working intermittently before displaying ERR IGN

Can you reset a Pentair poolheater to clear the ERR IGN code?

After cleaning the flame sensor or replacing the igniter, perform a soft reset: press ON/OFF, wait 30 seconds, then press ON. The heater will attempt a new ignition sequence. If the heater has tripped the internal lockout counter, you may need to perform a hard reset (gas off + breaker off 60 seconds) to clear all lockout flags.

Tools Required for Diagnosis

MultimeterFine steel woolScrewdriver setManometer (for gas pressure)

Diagnostic Checklist

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

1

Confirm gas supply

Confirm gas supply: verify the manual gas shutoff valve at the heater is fully open (handle parallel to pipe). Check that other gas appliances in the home (furnace, stove) are functioning normally.

2

Locate the flame sensor rod (also called the flame rectification rod)

3

Test the hot surface igniter with a multimeter set to resistance

4

During an ignition attempt

5

With gas valve confirmed receiving 24VAC

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name
Hot surface igniter42001-0052S · $25–$55
Flame sensor rod42001-0053S · $15–$30
Gas valve assembly472736 · $150–$350

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs
Labor Approach
Our Verdict
REPAIR
Estimated Cost: $183 (Parts) vs $3000 (New Machine)

Frequently Asked Questions

What does ERR IGN mean on a Pentair MasterTemp pool heater?
ERR IGN means the heater attempted ignition multiple times and could not establish a stable flame. It enters a hard lockout to prevent unburned gas from accumulating. The heater must be manually reset after fixing the underlying cause.
How do I clean the flame sensor on a Pentair pool heater?
Shut off the gas and breaker, then remove the flame sensor rod by disconnecting its single wire and removing the mounting screw. Gently rub the metal tip with fine steel wool to remove the carbon or oxide layer. Do not use sandpaper or abrasives that leave residue. Reinstall and test.
Can low gas pressure cause ERR IGN on a Pentair heater?
Yes. The MasterTemp gas valve requires adequate inlet pressure (typically 5 to 14 inches water column for natural gas) to open and maintain burner flame. Low gas pressure from a partially closed valve, undersized gas line, or utility supply issue can cause repeated ignition failures.
How do I know if my Pentair igniter is bad?
Remove the igniter and test it with a multimeter on the resistance setting. A good hot surface igniter reads 50 to 200 ohms. An open reading (OL on the meter) means the element is broken. You can also observe ignition - the igniter should glow bright orange within 30 seconds.
How much does it cost to fix ERR IGN on a Pentair pool heater?
Cleaning the flame sensor is free. A replacement igniter is $25 to $55. A flame sensor rod is $15 to $30. A gas valve is $150 to $350 for the part alone. Professional labor to diagnose and replace ignition components typically runs $150 to $300.

Related Pentair Poolheater Error Codes

Code: HUBPentair Pool Heater Error Codes GuideCode: E05Pentair Pool Heater E05 Error CodeCode: RESETHow to Reset a Pentair Pool Heater

Same Fix on Other Brands

Hayward poolheaterIF: Hayward Pool Heater IF Error CodeHayward poolheater10: Hayward Pool Heater Code 10

Models Known to Experience ERR IGN Errors

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

MasterTemp 400, MasterTemp 250, MasterTemp 300, MasterTemp 125

Last verified for technical accuracy on March 14, 2026