Does Your Pool Heater Have a Pilot Light? Millivolt vs. Electronic Ignition

Quick answer

If your pool heater was made in the last 15-20 years, it almost certainly does not have a standing pilot light — Pentair, Hayward, Jandy, and Raypak’s own Digital series all switched to electronic hot-surface ignition, which only fires when the heater actually calls for heat. The one notable holdout is Raypak, which still manufactures true millivolt (pilot-light) models like the P-R206A and P-R266A today, specifically for equipment pads without electrical service nearby, according to Raypak’s own technical comparison. A millivolt pilot that keeps going out is almost always a weak or dirty thermocouple, not a bad gas supply — that’s the first thing to check before assuming you need a technician.

Millivolt vs. electronic ignition, side by side

Why most pool heaters stopped using a pilot light

A standing pilot light sounds simple, but it has real downsides once you know what to look for. Raypak’s own comparison of its Digital and Millivolt lines lists the practical problems directly: a pilot that burns around the clock wastes gas even when the pool doesn’t need heat, the warm, sheltered pilot chamber attracts pests — Raypak specifically flags spider webs clogging burner ports and rodents chewing on components as real field issues — and a strong gust of wind across the burner compartment can snuff the flame out entirely, shutting the heater down until someone relights it. Electronic hot-surface ignition solves all three: it only burns gas while actively heating, there’s no continuous warm chamber to attract pests, and most systems auto-relight if a flame does go out. That combination is why electronic ignition is now standard on Pentair MasterTemp and Max-E-Therm heaters, Hayward’s Universal H-Series, and Jandy’s JXi line — see our gas vs. heat pump guide if you’re still deciding between fuel types before ignition type even enters the picture.

The exception: Raypak still sells millivolt models

Here’s the honesty-hook worth knowing before you assume your heater can’t possibly have a pilot light: Raypak still manufactures and actively sells millivolt models — the P-R206A and P-R266A among them — precisely because some equipment pads genuinely don’t have electrical service run to them, and running new electrical conduit to a heater pad can cost more than the heater itself. A millivolt heater needs zero external power to operate; the pilot flame itself, via a thermopile, generates enough current to run the gas valve and safety controls. The tradeoff is everything in the table above — no remote control, no auto-relight, and continuous fuel draw — which is exactly why California now prohibits installing new millivolt-ignition heaters on natural gas, per Raypak’s own technical notes, even though propane and remote-pad installs elsewhere still use them. If you’re shopping and unsure which ignition type a specific Raypak model uses, our Raypak buying guide and manual guide both cover how to pin down an exact model number before you buy or troubleshoot.

How to tell which type you actually have

Open the burner access door and look. A millivolt heater has a small, dedicated pilot burner with its own gas tube and a visible thermocouple probe sitting in the pilot flame, plus a pilot-light knob (often marked Pilot/Off/On) on the gas valve itself. An electronic-ignition heater has no separate pilot burner at all — instead there’s a ceramic or silicon-nitride hot-surface element that glows red when the heater fires, wired to a control board rather than a gas valve knob. If your heater has a digital display and a control board with buttons, it’s electronic; if it has a simple dial thermostat and a knob you turn to “Pilot” before pushing a red button, it’s millivolt.

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Fixing a millivolt pilot that won’t stay lit

Work through this in order, since the fixes go from free to a real part cost. First, hold the pilot button down a full 30-60 seconds after the flame catches before letting go — releasing too early is the single most common reason a pilot appears to relight and then dies again, since the thermocouple needs that long to heat up enough to hold the gas valve open on its own. If that doesn’t hold it, shut the gas off, let everything cool, and clean any visible dust or soot off the thermocouple tip and the pilot orifice with a soft brush — years of pool-chemical off-gassing and dust buildup around an equipment pad can partially block either one. If cleaning doesn’t fix it, the thermocouple itself has likely weakened with age and needs replacing; it’s an inexpensive, DIY-friendly part on most units. Wind is the other common cause worth ruling out — a pilot that lights fine indoors-adjacent but keeps blowing out on a gusty equipment pad may need a windscreen or a burner-compartment door that seals better, not a new part at all. If none of that holds a flame, or the heater is short-cycling on top of the pilot problem, work through our full not-heating troubleshooting guide next, since flow and gas-supply issues can mimic a pilot problem.

The bottom line

If you’re searching for how to light your pool heater’s pilot and can’t find one, that’s normal — the large majority of gas pool heaters sold in the last two decades use electronic ignition with no pilot to speak of, and the real question is usually why the heater isn’t firing at all, not how to relight a flame. If you do have a genuine standing pilot, it’s most likely a Raypak millivolt model installed because the equipment pad has no electrical service, and a pilot that won’t hold is almost always a thermocouple problem you can diagnose in five minutes and fix yourself for under $20. For anything beyond a stuck pilot — repeated lockouts, a burner that won’t fire even with a good pilot, or a fault code on a digital model — our repair cost guide breaks down when it’s worth calling a pro instead.

Sources: Raypak — Digital vs. Millivolt Pool Heaters, Raypak — Millivolt Ignition Product Listings, TroubleFreePool.com — Millivolt or Electronic Pool Heater Discussion