Raypak Digital Ignition Diagnostic Guide
• Applies to: Digital 206A-406A, Digital Low NOx 207A-407A, Professional 268A-408A, X94/SR410, Above-Ground 106A-156A
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Raypak Digital Ignition Diagnostic Guide
Raypak's Digital 206A-406A, Digital Low NOx ASME 207A-407A, Professional 268A-408A, Professional Series X94/SR410, and Above-Ground 106A-156A gas heaters share the same LCD-based digital ignition control. When a fault occurs, the display flashes a fault message that maps directly to a Diagnostic Readouts table in each manual. The checks below come from that shared table plus each manual's mechanical troubleshooting section.
Diagnostic Readouts (LCD Fault Text)
These come from the "Control Logic Flow Chart" in each manual and are worded almost identically across all five models.
| Display Reads | Manual-backed cause | Field check |
|---|---|---|
| "Sensor Failure," "Sensor Open," or "Sensor Short" | Temperature sensor out of range | Inspect the thermistor, wires, and connector at Terminal P1. Check resistance against the chart. Replace the thermistor if not within 10% of chart values; if okay, replace the circuit board. |
| "Water Sw Open" | Water flow/pressure switch issue | Verify water flow and pressure. Clean the filter or strainer before condemning the switch. |
| "Hi Limit 1 Fault" / "Hi Limit 2 Fault" | High limit switch open | Verify water flow, inspect the internal thermostat and bypass valve. On ASME units this is a manual-reset device — press the MODE button to reset. |
| "Rollout Sw Open" | Rollout sensor tripped | Check for a blocked heat exchanger or soot buildup, then press the manual reset button. |
| "Clock/Fireman Sw" | Fireman or remote switch in the safety loop is OFF | Check the fireman switch or remote control wiring for an open condition. |
| "Vent/Field Sw #1" | Vent switch open | Check connections to the board; if an extractor is installed, troubleshoot the extractor. |
| "Ignition Lockout" | Pilot flame not established, or lost during trial for main burner | Check power at the pilot valve, check for spark, and verify a clean pilot orifice with proper clearance from igniter to ground rod. |
| "Ignition Failure" | Gas supply or valve operation issue | Verify gas is reaching the heater and confirm valve operation. |
| "EOL" at startup | Stuck MODE button | Check the MODE button on the control panel for a stuck or jammed switch. |
Mechanical Symptoms (Shared Across All Five Models)
| Symptom | Manual-backed checks |
|---|---|
| Harmonics or whining noise | Check U.G. (unitized gas valve) movement in hot water above 110°F. Look for debris or restriction in the water or gas line. Low flow can allow scale to form in the heat exchanger — check pool pH and total alkalinity. |
| Heater cycles on and off continuously | Clean or replace a dirty filter, raise a low pool water level, adjust the external bypass, or adjust an out-of-spec pressure switch. |
| Liming or scale forming in the exchanger | Correct pool water chemistry first. Inspect the bypass for movement and replace if none; replace the U.G. if it doesn't move when heated. |
| Sooting | Reduce high flow rates with a manual bypass valve (target 105-110°F outlet). Check U.G. movement, air starvation, improper venting, and insects or debris clogging burner intake ports. |
| Pilot outage or "weak flame" signal | Adjust low gas pressure, clean a restricted or dirty pilot, or replace a weak pilot generator. |
| Yellow, lazy flame | Adjust low gas pressure and clean burner intake ports of insects or debris. |
| Takes too long to heat pool or spa | Confirm the heater isn't undersized for the pool gallonage, reset the time clock for adequate filter run time, clean a dirty filter, and confirm the gas line/meter is sized correctly. |
| Leaking at well or heat exchanger, or brittle/leaking gasket | Overacid water is the most common cause — correct water chemistry and replace the affected part. A gasket that's overheated because the heater runs after the pump shuts off points to the pressure switch adjustment. |
Model Notes
- Digital 206A-406A and Digital Low NOx ASME 207A-407A share nearly word-for-word diagnostic readout tables; the ASME line adds manual-reset language on Hi Limit faults.
- Professional 268A-408A uses the same flow chart structure, routing "Sensor Failure," "Water Sw Open," and "Hi Limit Fault" through the same Diagnostic Readouts step.
- Professional Series X94/SR410 is the only model in this group documenting the "EOL" stuck-MODE-button condition and a 10-fault history accessible from the front touchpad.
- Above-Ground 106A-156A covers both the P-106 and P-156 controls; the P-156 adds a full digital thermostat with the same Diagnostic Readouts table structure as the other four models.