Richmond tankless water heater cycles on and off rapidly when a hot water tap is barely open (temperature swings, short cycling).

Safety first: No special hazards beyond hot water—use caution to avoid scalding.

• Increase flow: Open the hot water tap further to exceed the heater's minimum flow rate. Many Richmond tankless units require around 0.4–0.6 gpm to stay lit.
• Clean aerators: Remove and clean faucet aerators and showerheads to restore proper flow.
• Adjust usage: Avoid using the tankless heater for extremely low-flow applications (e.g., trickle handwashing). Combine hot water demands where possible.
• Service flow sensor: If cycling occurs even at higher flows, clean or replace the flow sensor as described in the E8/flow sensor entry.