Richmond tankless heater displays E2 and shuts down shortly after attempting to fire.

Safety first: Turn OFF power and gas before opening the unit. Venting issues can cause carbon monoxide hazards—work in a well-ventilated area.

• Check venting system: Inspect the entire intake/exhaust vent run for sags, disconnections, or blockages. Ensure vent length and diameter match Richmond specifications for your model. Correct any improper slopes or joints.
• Clean flame sensor: Remove the front cover and locate the flame sensor rod. Gently clean with fine abrasive pad to remove oxidation. Reinstall securely.
• Verify combustion air: Make sure the heater has adequate combustion air. In tight mechanical rooms, ensure louvered doors or combustion air openings are not blocked.
• Monitor gas supply: If other gas appliances flicker or go out, you may have a supply or regulator issue. Contact a licensed gas technician to measure inlet and manifold pressure while the heater is running.
• Professional service: If E2 persists, the gas valve assembly or control board may be malfunctioning and should be tested and replaced by a qualified technician.