Display shows 'IF' and heater attempts to light but fails; you may hear clicking or see ignition attempts.

Safety first: Turn off power and gas before removing access panels. Gas leaks and ignition failures can be hazardous.

Steps to address IF error:

• Verify gas supply: Ensure the main gas shutoff to the heater is open. Confirm other gas appliances on the same line are operating normally.
• Check for recent gas work: If the gas line was recently serviced, air may be trapped. Multiple ignition attempts may be needed, but do not repeatedly reset without checking for leaks.
• Inspect igniter: Locate the hot surface igniter or spark igniter. Look for cracks, chips, or heavy deposits. A visibly damaged igniter must be replaced.
• Check igniter wiring: Ensure the igniter harness is firmly connected to the ignition control module and not pinched or burned.
• Observe ignition sequence: With panels in place and gas/power restored, watch through the sight glass. Confirm that the igniter glows (for HSI) or sparks, and that gas is being delivered (you should see flame within a few seconds). If igniter operates but no flame appears, gas valve or supply issues are likely.
• Professional checks: Gas pressure, manifold pressure, and ignition control timing should be checked by a qualified technician. Replace the igniter or gas valve only after proper diagnosis.

Warning: Never attempt to manually light a Raypak electronic ignition heater.