Noritz tankless water heater code Er43
Burner high limit switch fault. Code Er43 means the same thing on all 2 Noritz series documented here — but the fix, and what it costs, is still worth reading for your exact unit.
What code Er43 means on each Noritz series
| Series | What it means | Verdict | Typical cost |
|---|---|---|---|
| NRCP | Burner high limit switch fault | Call a pro | $0–$1,200 |
| NRCP Eco TOUGH | Burner high limit switch fault | Call a pro | $200–$1,200 |
Each row opens the full page for that generation. We hold manuals for NRCP and NRCP Eco TOUGH, and each one gets its own reading of code Er43 — what Noritz documents, what you can safely check yourself, and what the repair should cost.
What each manual actually says
The table above compares 2 series in four columns, which is enough to route you and not enough to explain anything. This is the Noritz wording behind each row, one entry per manual, so you can see where the 2 readings of code Er43 agree and where they part company.
NRCP — Burner high limit switch fault
The high limit switch at the burner has tripped. Noritz's remedies are to check the flame condition through the burner window, check the air intake filter, and check for gasket damage around the burner. The last one matters: a failed gasket on a sealed combustion chamber lets combustion products where they should not be.
NRCP Eco TOUGH — Burner high limit switch fault
The high limit switch at the burner has tripped. Noritz's remedy on this generation is one line — contact technical support — where the first-generation manual lists the burner window, the air intake filter and burner gasket damage. Manual reset.
Does it matter which Noritz you have?
NRCP and NRCP Eco TOUGH all route code Er43 the same way: a professional, at $0–$1,200. That makes it one of the Noritz numbers you can act on before working out which unit you own.
Which Noritz do you have?
On the 2 series that report code Er43, the model number on the rating label starts NRCP — match yours against the 4 listed below. You can also use the full model-number decoder.
Where this comes from
Source: Noritz Service Manual — NRCP111-DV / NRCP98-DV (Rev. 09/19) (p. 62), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Source: Noritz Service Manual — NRCP1112-DV / NRCP982-DV Eco TOUGH (Rev. 05/19) (p. 58), read Sep 2026 — the manufacturer's own documentation for this Noritz range.
Parts, guides and symptoms behind code Er43
Code Er43 on these 2 Noritz series points at 1 guide, 3 parts and 2 symptoms, each named by the manufacturer's own procedure for this code.