Rheem Tankless Gas Code 93
Neutralizer must be replaced (lockout). High-efficiency (condensing) units only, and the escalation of code 92: the unit will not operate until the neutralizer is replaced. Where 92 is a warning you can run past for a while, 93 is the stop.
Part replacementThe verdict
Replace a part
No hot water until the neutralizer is changed, so this one has a deadline attached. The part itself is modest; what costs is the waiting, since the kit is ordered through a Rheem or Ruud supplier.
Typical cost: $50–$400
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. 95), read Aug 2026 — the manufacturer's own documentation for this exact series.
What you can safely check
- Order the neutralizer kit through a Rheem or Ruud supplier.
- If you need hot water sooner, ask your installer whether they stock one.
- Do not attempt to bypass the neutralizer to get the unit running — that puts acidic condensate straight into your drain.
Frequently asked questions
Did I miss a warning before this?
Probably code 92, which says the same thing while still letting the unit run. If you never saw it, it is worth asking why — a warning nobody looks at is the same as no warning.