Which blink code list applies, Rheem furnaces: Rheem publishes two blink code lists that contradict each other

Rheem's standard gas furnace flash code list and the sequence-of-operation blink codes in the *RC 92+ and *RL 90+ installation instructions disagree on three of the first four counts. Counting blinks on a Rheem is not enough — you have to know which control you are looking at.

Applies to: Rheem, Ruud and Weather King gas furnaces. Read this before acting on any Rheem blink count, because the same count means different things on different Rheem platforms.

What it means

Rheem publishes a short list of diagnostic flash codes on its technical support site, and states plainly at the top that it does not cover modulating, LXE or two-stage furnaces. Separately, the installation instructions for the *RC 92+ upflow and *RL 90+ downflow condensing furnaces describe blink codes inside the sequence of operation rather than in a table. The two do not agree. On the standard list one blink is a one-hour soft lockout, three blinks is an open limit switch, and four blinks is a pressure switch stuck closed. On the condensing furnace instructions one blink is an open limit circuit, three blinks is a pressure switch stuck closed, and four blinks is lockout after five failed ignition attempts. Only two blinks means the same thing on both — a pressure switch that will not close. This is not a contradiction in the documents so much as two different control platforms sold under one brand, but the practical effect is the same: a count read off the wrong list produces the wrong repair.

The two lists side by side

Every count this site documents for both Rheem platforms, in one table. Each cell's meaning has its own page, reachable from the Rheem hub.

Reading the table by fault instead of by count shows the trap from the other side. An open limit is three blinks on the standard list but one blink on the condensing list. A pressure switch stuck closed is four blinks on the standard list but three on the condensing list. Both platforms have an hour-timed ignition lockout — one blink on the standard list, four on the condensing list. Only the pressure-switch-will-not-close fault keeps its count, at two blinks on both. So three of the four shared faults change number between the lists, and every shared number except two changes fault.

Most common causes

• The two lists come from different control platforms, not from an error in either document.
• Rheem's standard flash code page explicitly excludes modulating, LXE and two-stage furnaces from its scope.
• The *RC 92+ and *RL 90+ instructions describe their codes in the sequence of operation rather than in a labelled table, so they are easy to miss.
• Rheem, Ruud and Weather King are the same equipment under different names, so the ambiguity carries across all three.

How to diagnose it

1. Find the model number on the rating plate inside the furnace cabinet before counting anything.
2. A model beginning RC or RL, or described as a 92+ or 90+ condensing furnace, points at the condensing instructions list.
3. If the furnace is modulating, two-stage, or an LXE model, the standard flash code list does not apply to it at all — Rheem says so directly.
4. If the model cannot be identified, treat a blink count as ambiguous rather than guessing, and have a technician confirm against the documentation for that specific unit.

How to fix it

1. There is nothing to fix here. This page exists so a count is not acted on against the wrong list.
2. Once the platform is identified, follow the matching page on this site.
3. If the two readings suggest different faults and the model is unclear, the safer of the two interpretations is the one to act on first.

Do it yourself or call someone

Identification is the homeowner job here, and it is the whole job. Finding the model number on the rating plate inside the furnace cabinet requires opening the access door, not the burner compartment, and an RC or RL prefix settles which list applies before anything else is touched. That five-minute check has a direct cash value: a technician dispatched against the wrong list arrives expecting the wrong fault, and the diagnostic fee — typically $75–150 per the furnace repair cost guide, credited only if a repair follows — buys less when the first half of the visit is spent undoing a wrong assumption. If the model genuinely cannot be identified, say so when booking rather than guessing, and note that the faults behind these counts span the whole price range, from an $80–200 flame sensor cleaning to $300–900 inducer or gas valve work, so no useful budget exists until the list is known.

Notes

This is the second manufacturer on this site with the same problem. Heil, Tempstar and Comfortmaker have it too, for a different reason — one of their documents describes the control board and the other a Honeywell SmartValve. In both cases the failure mode for a reader is identical: a confident answer from the wrong table. Nor are two the end of it: the site's same code, different meanings page collects the pattern across manufacturers, and York, Lennox and Trane each have their own version of the two-list problem. Rheem's is arguably the sharpest, because both lists use plain counts of the same red LED on furnaces sold under the same three brand names.

Related

• 1 blink — Soft lockout, one hour
• Which diagnostic system you have — Heil, Tempstar and Comfortmaker furnaces use two different code systems that contradict each other

All codes for this manufacturer

Rheem, Ruud and Weather King furnace blink codes — every code, with what differs between models.

What the fix costs

Nothing on this page has a repair price of its own, because the page exists to stop the wrong repair from being priced. The ranges that matter travel with the faults, not the counts: an open limit, a pressure switch fault, an ignition lockout and a twinning fault each carry their own typical costs, quoted on the individual code pages in the table above once the right list is identified. The only cost unique to this page is the avoidable one — a diagnostic visit spent on the wrong platform's fault.

What this looks like

From the outside, this usually shows up as the vents blowing cold air on a heat call — that walkthrough covers what to check in order, and when it stops being a homeowner job.

Sources

• Rheem Professional Technical Support — Standard Gas Furnace Diagnostic Flash Codes
• Rheem Gas Furnaces Installation Instructions 708503a — *RC 92+ Full Size Upflow and *RL 90+ Full Size Downflow Condensing Furnaces, Sequence of Operation