Rheem Tankless Gas Code 16
Outlet water above the set point. The outlet water temperature is above what the remote control is set to. Milder than codes 14 and 15 in what it reports, but the same family of problem: the unit is putting more heat into the water than it intended to.
Call a proThe verdict
Call a licensed plumber
Water hotter than you asked for is a scald risk before it is a repair question, especially with a set point at the higher end. Have it checked rather than compensating at the tap — the causes overlap with the overheat codes.
Typical cost: $150–$900
US estimate for parts and labor. Prices vary by region and by who does the work — see how we estimate costs.
What the manual says
The meaning above is transcribed from the manufacturer's diagnostic documentation for the Tankless Gas — not averaged across the brand.
Source: Rheem Tankless Gas Troubleshooting Pocket Manual (SVC820) (p. 53), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
Before anything else: if you smell gas, stop here, leave, and call your gas utility.
- Be careful at the tap until it is fixed — the water may be hotter than the display says.
- Note when the unit was last flushed.
- Book a licensed professional.
Frequently asked questions
Should I just lower the set point?
No. The complaint is that the unit is exceeding whatever set point you choose, so lowering it moves the number without fixing the overshoot.