Heater runs but does not heat water effectively; temperature rises very slowly

Safety: Turn off gas and power before opening burner or manifold sections.

• Confirm gas input: Verify that the gas supply and meter/regulator are sized for the Sta-Rite heater's BTU rating. Have a gas technician measure input rate.
• Inspect burners: Remove and clean the burner tray, clearing rust and debris from burner ports.
• Check internal bypass: On models with an internal bypass, inspect for a stuck-open bypass that can reduce heat transfer. Replace the Sta-Rite internal bypass assembly if damaged.
• Descale heat exchanger: If the heater is older or used with hard water, perform a chemical descaling of the Sta-Rite heat exchanger following manufacturer-approved procedures.