The most likely fix on a Raypak fault code: power-cycle the breaker once, then look at gas. In our field experience, the big four fault families — IF (Ignition Failure), IGN (ignition sequence), OS1 (outlet sensor), and ILO(Ignition Lockout) — resolve to gas-supply or sensor issues a large share of the time. Resetting the same fault three times in a row without checking gas pressure is how heaters get sent for parts they don't need. Note that exact code labels and reset sequences vary across the Raypak digital-display lines (106A, 206A, R-series, Avia, Versa) — always verify against the service manual that shipped with your unit.
Raypak error-code quick reference
| Code / symptom | What it means | Likely cause | DIY or pro? |
|---|---|---|---|
| IF | Ignition Failure — three attempts, no flame proven | Closed gas valve, dirty igniter, corroded flame rod, condensate, or low inlet gas pressure | DIY first, then pro |
| IGN | Ignition sequence in progress — not a fault | Normal purge and light cycle | DIY |
| ILO | Ignition Lockout — the heater has stopped trying | Real combustion or gas-supply issue if it repeats after one reset | DIY first, then pro |
| OS1 | Outlet sensor fault | Failed sensor or a damaged, corroded harness | Pro |
| AFS | Air flow switch on the combustion blower didn't close | Vent obstruction, failed blower, or a clogged pressure-tap tube | Pro |
| HLS | Heat exchanger got too hot | Restricted water flow, scaled exchanger, or an actual sensor fault | DIY first, then pro |
Most common symptoms
- Display shows two- or three-letter code; heater will not fire.
- Heater attempts to light, fails, retries twice, then locks out.
- Heater fires briefly then drops out, sometimes with a soft thud.
- Display reads OS1 with the heater otherwise looking fine.
- Heater works in cool weather but locks out under load on hot days.
Field-fix list by code
- IF — Ignition Failure. Three attempts, no flame proven. Check gas valve open, igniter clean, flame rod free of corrosion, condensate cleared, and inlet gas pressure under full fire.
- IGN — Ignition sequence. Not a fault. The heater is in the purge/light cycle.
- ILO — Ignition Lockout. The heater has stopped trying. Reset, then diagnose. ILO repeating after one reset = real combustion issue.
- OS1 — Outlet Sensor. Sensor or wire fault. Replace the sensor; check the harness for damage.
- AFS — Air Flow Switch. Pressure switch on the combustion blower didn't close. Vent obstruction (a bird's nest or a stuck damper), failed blower, or a clogged pressure-tap tube.
- HLS — High Limit Switch. The heat exchanger got too hot. Restricted flow, scaled exchanger, or an actual sensor fault. Check water flow and exchanger condition before suspecting the switch.
Diagnostic walkthrough
- Photograph the code. Some Raypaks blink the code; the photo prevents a misread.
- Gas first. Verify the supply at the meter. Try a kitchen burner — gas at the house? Then the fault is downstream at the heater regulator or line.
- Flow second. Pump running, valves open, filter pressure within range. Most HLS faults clear when flow comes back.
- Power-cycle once. Breaker off 30 seconds, on again. One reset attempt; if the same code returns within seconds of relight, stop and diagnose.
- Open the cabinet (pro work). Cabinet inspection for spider webs in the venturi (a Florida specialty), condensate puddles in the burner tray, corroded flame rod, and dirty igniter is licensed-tech work — gas off, breaker locked out, manometer in hand.
- Manometer test. The definitive call on IF/ILO. Gas pressure under full fire must hold to spec. Sag = supply problem.
Step-by-step fix
Clean the igniter and flame rod with fine emery cloth. Clear the burner tray of condensate and debris. Replace a failed sensor (OS1) with the matching part number. Manometer the gas; if it sags under load, the line is undersized or the regulator is failing — that is plumber/gas-fitter work. See our gas heater line sizing guide for what the supply should look like.
South Florida-specific failure modes
- Spider webs in the venturi. Florida outdoor heaters get spiders in the gas-air mixing tube. The webs choke combustion, you get IF or ILO every spring. Annual venturi cleaning prevents this.
- Condensate pooling in coastal cabinets. Cool nights + warm cabinets = condensation on the burner tray. Salt-laden condensate corrodes the flame rod. Inspect twice a year.
- Salt-air corrosion of low-voltage harness. The OS1 sensor harness rots at the connector within 5–7 years on coastal pads. Dielectric grease the connectors at install.
- Lightning damage to the ignition control board. Florida summer storms take out IFC boards faster than the burner ever fails.
When it's time to replace
A Raypak heat exchanger that has failed (water through the burner) is end-of-life. A 12+ year heater with a failed control board, a corroded burner, and a leaking exchanger is replace, not repair. See our pool heaters comparison for what comes next — gas, heat pump, or solar.
When to call a pro
Manometer testing, regulator work, and burner-tray inspection are licensed-tech jobs. A heater is gas, fire, and water in one cabinet — not the place to learn. In Florida, pool heater repair work is regulated by the DBPR (RP / CPC license categories), and gas-side work also requires a licensed gas-fitter. Schedule a pool equipment repair visit and we will diagnose with a flat-rate quote.
Frequently asked questions
IF stands for Ignition Failure. The heater attempted to light, didn't sense flame, and locked out. Causes: gas valve closed, low gas pressure, dirty igniter, fouled flame-rectification rod, or condensate drowning the burner tray. Reset by power-cycling at the breaker, then diagnose before relighting.
IGN is the ignition sequence in progress — not a fault. It appears for the few seconds the heater is purging and lighting. If IGN persists for more than 30 seconds without a flame, it will roll over to IF (Ignition Failure).
OS1 is an Outlet Sensor open or short condition. The water-temperature sensor at the heat exchanger outlet has failed or its wiring is broken. Replace the sensor; on rare occasion the harness has been chewed by rodents in a Florida outdoor cabinet.
ILO is Ignition Lockout — the heater has tried three times to light and failed each time. It will sit locked out until you power-cycle. Don't keep resetting blindly; ILO almost always means low gas pressure under load or a real combustion issue.
Most Raypak digital displays use the same core code list (IF, IGN, OS1, ILO, AFS, HLS) but the specific wording and reset sequences vary across the 106A, 206A, R206/R406, and Avia models. Confirm against the heater's data plate or service manual.
AFS means the air flow switch on the combustion blower didn't close, so the heater can't prove airflow. The usual causes are a vent obstruction — a bird's nest or a stuck damper — a failed blower, or a clogged pressure-tap tube. This one is pro work; the blower and vent inspection happen inside the cabinet.
HLS is the high limit switch — the heat exchanger got too hot. Check water flow first: pump running, valves open, filter pressure within range. Most HLS faults clear when flow comes back. If flow is good, suspect a scaled exchanger or an actual sensor fault, and that's a tech call.
Power-cycle at the breaker: off for 30 seconds, then back on. Give it one reset attempt only. If the same code returns within seconds of relight, stop and diagnose — resetting the same fault three times in a row without checking gas pressure is how heaters get sent for parts they don't need.
Spider webs in the venturi. Florida outdoor heaters get spiders in the gas-air mixing tube, the webs choke combustion, and you get IF or ILO the first time you call for heat in spring. Annual venturi cleaning prevents it. Coastal cabinets also pool condensate on the burner tray, and that salt-laden condensate corrodes the flame rod.
A failed heat exchanger — water through the burner — is end-of-life. A heater 12-plus years old with a failed control board, a corroded burner, and a leaking exchanger is a replace, not a repair. From there the decision is what comes next: gas, heat pump, or solar.
Raypak still locked out?
We repair Raypak heaters across Palm Beach and Broward — same-day diagnosis on most routes, flat-rate quote before any work.