Pilot Light & Ignition Problems

A gas water heater that won't light, or won't stay lit, is one of the most common reasons for a "no hot water" call.

Safety First

If you ever smell gas, leave the house immediately and call your gas utility or emergency services from outside. Don't attempt to relight a pilot or troubleshoot the gas valve yourself, that's a job for a technician.

Common Causes

A failed thermocouple is the classic cause of a pilot that won't stay lit, its job is to sense the flame and keep gas flowing, and once it fails, the safety system shuts gas off. On newer units with electronic ignition, a bad igniter, control board, or a buildup of debris can prevent ignition entirely.

Does Hard Water Play a Role?

Not directly on the ignition components themselves, but heavy scale buildup elsewhere in an older tank sometimes coincides with ignition issues simply because the unit as a whole is reaching the end of its service life. A technician will check both independently.

How It Gets Fixed

The technician diagnoses whether it's the thermocouple, igniter, gas valve, or control board, and replaces the failed part. Most single-part ignition repairs are done in one visit.

When a Draft Is the Real Problem

A pilot that lights fine but blows out repeatedly, especially in a garage or exterior closet, sometimes points to an airflow or venting issue rather than a failed thermocouple. Wind, a door left open near the unit, or a venting problem can all cause this. The technician checks placement and venting alongside the ignition components themselves, so you're not paying to replace a part that was never actually the problem.

Exterior Closet Units See This More Often

Units in exterior closets are more exposed to wind and temperature swings than a garage unit, which can make pilot and ignition issues slightly more frequent there. It's not a design flaw, it's just more exposure, and a properly sealed and vented closet largely offsets the difference.

Standing Pilot vs. Electronic Ignition

Older gas units use a standing pilot, a small flame that burns continuously and needs manual relighting if it goes out. Newer units use electronic ignition, sparking a flame only when hot water is called for, which saves a small amount of gas but introduces its own set of components, igniters and control boards, that can fail differently than a simple pilot and thermocouple setup.

Before You Call

Note whether your unit has a visible pilot flame or a fully electronic ignition system, whether you smell gas at all (if so, stop and follow the safety guidance above instead of troubleshooting), and how long the unit has been failing to light or stay lit. That context helps the technician arrive prepared for your specific system.

Wind and Draft Considerations

Units installed near frequently-opened doors or in breezy locations can experience a pilot that blows out repeatedly even when every internal component is functioning correctly. A wind guard or adjustment to the unit's draft hood sometimes resolves this without replacing any parts at all.

Checking for a Broader Gas Supply Issue

If multiple gas appliances in your home are acting up around the same time, not just the water heater, that points toward a supply-side issue, a partially closed main valve or a utility-side problem, rather than an isolated water heater fault. Mention this pattern if you notice it.

Do Ignition Issues Follow a Season?

Not strongly in Arizona's climate, since temperature swings that affect gas appliances elsewhere are less pronounced here. Most ignition issues here trace to component age and wear rather than any seasonal trigger.

Typical Lifespan of Ignition Components

A thermocouple or igniter doesn't have a fixed replacement schedule the way a filter might, but these parts do wear with age and repeated cycling, so a unit past eight to ten years old experiencing its first ignition issue is often just reaching that natural point rather than something unusual.

What to Expect Right After the Fix

Once the pilot or ignition issue is resolved, hot water typically returns to normal within the time it takes the tank to reheat from wherever it had cooled to. If the same issue recurs within a short window after a repair, that's worth a follow-up call rather than repeating the same fix indefinitely.

When Ignition Issues Signal Replacement Time

A unit needing its second or third ignition-related repair within a couple of years, especially alongside other age-related signs, is often better served by replacement than another round of parts. The technician gives you a straightforward comparison rather than defaulting to the smaller, immediate fix if it's not truly the better value.

Getting the Right Technician the First Time

Ignition troubleshooting benefits from a technician who's seen the full range of common causes across many units, not someone guessing through a checklist for the first time. Our network prioritizes that depth of experience so the actual cause gets identified efficiently rather than through repeated trial visits.

The Bottom Line on Ignition Problems

A pilot or ignition issue is rarely a sign of something catastrophic, it's usually a single worn component doing exactly what worn components eventually do. A straightforward diagnosis and a straightforward fix is the typical outcome, not something to dread calling about.

A Note on Not Overthinking This

It's easy to feel uncertain about anything gas-related, but the actual fix for most ignition issues is a routine, well-understood repair for an experienced technician. There's no need to worry that this is more complicated or risky than it typically is.

Understanding This in the Context of Tank Age

An ignition issue on a relatively new unit is usually an isolated component failure with no broader implication. The same issue on a tank already past eight to ten years is more often one signal among several worth considering together, which is why the technician looks at overall tank condition, not just the ignition system, when making a recommendation on an older unit.

One Last Consideration

If this is happening on a rental property, make sure tenants know to report it immediately rather than attempting to relight anything themselves, both for their safety and to avoid delaying a straightforward fix.

Keeping Your Manual Accessible

Your unit's manual typically includes a troubleshooting section specific to your model's ignition system, worth keeping in an accessible spot, a kitchen drawer or a digital photo, rather than filed away somewhere hard to find when you actually need it.

A Final Practical Note

If your unit has an indicator light or display showing ignition status, familiarizing yourself with what normal operation looks like makes it easier to notice quickly when something's actually wrong.

Last Thought

This is one of the more common, most reliably diagnosed issues we handle, rarely anything to be overly concerned about once properly addressed by an experienced technician.

Frequently Asked Questions