Ignition failure on a Raypak boiler almost always traces back to one of a handful of causes, and a technician's diagnostic path follows that list in a specific order.
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Quick answer
Ignition failure on a Raypak boiler means the control board attempted to light the burner and did not detect a successful flame within its normal window, which can stem from a gas supply issue, a fouled or misaligned igniter or electrode, a blocked burner, or a failed flame sensor signal. A licensed gas fitter diagnoses ignition failure by checking gas supply and pressure first, then the ignition components and flame sensing circuit, since guessing at parts without that sequence often replaces working components unnecessarily.
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When a Raypak boiler calls for heat, its control board runs a sequence: purge the combustion chamber, open the gas valve, energize the igniter, and confirm a flame within a set attempt window. Ignition failure means that sequence did not produce a confirmed flame, and after a set number of attempts the control locks out rather than continuing to try, which is a safety design, not a malfunction of the lockout itself.
From the homeowner's side, this usually shows up as the boiler cycling through an attempt -- sometimes audible as a click or a brief hum -- followed by silence and a fault indicator on the display, rather than the burner staying lit.
Gas supply comes first: is the manual shutoff valve open, is gas pressure at the correct level, and has any other gas appliance in the home recently been serviced or added that might affect supply. Next is the ignition components themselves -- the igniter or electrode can be fouled with debris, corroded, or out of the specified gap, any of which prevents a reliable spark or hot surface ignition.
Flame sensing is checked next, since some ignition failures are actually the control shutting down because it never confirmed the flame it did establish, due to a dirty or misaligned flame sensor rather than a true ignition problem. Finally, burner condition and venting are checked, since a partially blocked burner or restricted combustion air can prevent stable ignition even when the spark and gas supply are both working correctly.
| Cause | What it affects | Homeowner-safe check |
|---|---|---|
| Gas supply interrupted | No fuel reaches burner | Confirm shutoff valve is open |
| Fouled/misaligned igniter | No reliable spark | None; needs technician |
| Dirty flame sensor | Flame not confirmed | None; needs technician |
| Blocked burner or vent | Unstable or no ignition | Check outside vent terminal |
Each failed ignition attempt briefly opens the gas valve and introduces unburned gas into the combustion chamber before the control shuts it off. Repeated manual resets after a lockout multiply that exposure, which is why the control's built-in attempt limit and lockout exist. If the boiler fails to ignite more than once, the right response is to stop and call a technician rather than keep resetting.
Diagnosing which of these causes applies requires measuring gas pressure, inspecting and possibly cleaning or adjusting the igniter and flame sensor, and checking combustion airflow, all of which must be performed by a Technical Safety BC licensed gas fitter. CANRO holds gas licence LGA0043870 and boiler licence LBP0046450 for this category of work.
Safety note
If you ever smell gas, hear a hissing sound near the boiler, or notice soot, a burning smell, or headaches and drowsiness near the appliance, leave the home immediately and call FortisBC at 1-800-663-9911 from a safe location before doing anything else. Any work on gas piping, venting, or combustion components must be carried out by a Technical Safety BC licensed gas fitter.
The most common causes are an interrupted gas supply, a fouled or misaligned igniter, or a dirty flame sensor that prevents the control from confirming a flame it did establish. A licensed technician checks these in sequence to find the actual cause.
One reset is reasonable, but repeated resets after ignition failure repeatedly introduce unburned gas into the combustion chamber briefly, which is a real safety concern, not just an inconvenience. Call for service if it fails more than once.
Yes, restricted combustion air or exhaust flow can prevent stable ignition even when the gas supply and igniter are working normally, so checking the outside vent terminal is a reasonable first step.
A licensed gas fitter checks gas supply and pressure first, then inspects the igniter and flame sensor, and finally checks burner condition and venting, following that order rather than replacing parts by guesswork.
No, most ignition failures are traced to a specific component such as an igniter or flame sensor and are repairable. Replacement is a separate consideration tied to the boiler's overall age and condition, not a single ignition fault.
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