Raypak Digital gas heaters (the 206A through 406A and the AVIA line) tell you what is wrong on the display. Most of the codes point to one of four parts, and most of those are a half-hour fix for a technician or a confident owner. Here is what each code means, what to check before buying anything, and which part usually fixes it.
Before you read the code
Three checks solve a third of “broken heater” calls: the gas valve on the supply line is open, the pool pump is running at a speed that gives the heater enough flow (variable-speed pumps on low will not light a heater), and the filter is clean. A dirty filter drops the flow enough to trigger a water pressure fault.
The codes
LOW / water pressure (PS fault)
The heater is not seeing enough flow. Clean the filter and basket, raise pump speed, open any bypass valve. If flow is fine and the code stays, the pressure switch is stuck or out of adjustment. Part: Raypak 006737F pressure switch. On heaters installed above the pool water line the switch must be adjusted for the elevation; the manual has the procedure.
IGN / ignition failure / flame failure
The heater tried to light and did not sense flame. Listen for the clicking of the igniter. If you hear it but it does not light: gas pressure, a weak igniter or a dirty burner tray. If the igniter does not glow or click at all: the hot surface igniter is the usual culprit on Digital models. Part: Raypak hot surface igniter (confirm the part number for your model from the data plate; the 206A to 406A residential units use a different igniter than the Hi-Delta commercial line). If it lights and then shuts off after a few seconds, the flame sensor rod is dirty; clean it with fine sandpaper.
SPK (spark)
Older IID (spark-ignition) models: the ignition control is not getting a spark across the electrode. Check the electrode gap and wire, then the ignition control module.
Fan Fault / blower
On AVIA and newer Digital units the combustion blower did not reach speed, or its pressure switch did not close. Check for a blocked exhaust (wasps and leaves are common here) before replacing the blower or the air pressure switch.
HLS (high limit switch)
Water in the heat exchanger got too hot, usually from low flow or a scaled exchanger. Clean the filter first. Repeated HLS trips with good flow mean the exchanger is scaling, which is a water-chemistry problem (calcium too high, pH too high). If the switch trips with the heater cold, it has failed.
Service / Sensor / open or short
The water temperature sensor (thermistor) is reading out of range. The sensor is a cheap part that sits in a well on the inlet/outlet header; replace it rather than chase it.
Heater runs but water stays cold
Not a fault code, but common: the bypass valve inside the header is stuck open so water skips the exchanger, or the unitherm governor has failed. Both are internal header parts; this is a technician job.
Parts we keep in stock
Igniters, pressure switches, thermistors, high limits, gas valves, drain plugs and header gaskets for the Raypak Digital line are in Heater Parts. Have the heater model and serial from the data plate (right side of the cabinet) when you order; Raypak changed igniters and boards between generations, and the part number matters. Most parts ship for $7.99 or $14.99 and arrive in two to three days.
When to stop and call
Anything involving the gas valve, gas pressure or the heat exchanger is a job for a licensed technician. In Palm Beach, Martin and St. Lucie counties, Brite Water Pool Pros services Raypak heaters; call 1-877-650-POOLS. If the heater is more than 12 years old and needs an exchanger, the money is better spent on a new Raypak Digital or AVIA, which we install with the full warranty.
