Noritz NRCP Code Er12
Flame loss. The burner lit and the flame was lost. Noritz's remedies here are unusual for a flame code and worth reading literally: clean the intake air filter, and check or change the burner window by removing the flame sensor — noting that spare windows are in the emergency kit bag supplied with the unit. The burner window is the sight glass the flame sensor looks through, and a fouled one produces flame loss.
Also displayed as: 12, E12
Call a proThe verdict
Call a licensed plumber
The named causes are cheap — a dirty air filter and a fouled burner window, with spares in the box the unit came with. But reaching the window means removing the flame sensor from a gas appliance, so this is a service call with a good chance of a small bill.
Typical cost: $100–$700
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 NRCP — not averaged across the brand.
Source: Noritz Service Manual — NRCP111-DV / NRCP98-DV (Rev. 09/19) (p. 62), read Sep 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.
- Clean the intake air filter — that is the first remedy Noritz lists and it is a homeowner job.
- Find the emergency kit bag that came with the heater; Noritz says the spare burner windows are in it, and having it to hand saves a second visit.
- Call a licensed professional for the burner window itself — it means removing the flame sensor.
Frequently asked questions
What is the burner window and why do I have spares?
It is the sight glass the flame sensor looks through to confirm the burner is alight. It fouls with combustion deposits over time, and a fouled window looks to the sensor like no flame. Noritz ships spares in the emergency kit bag precisely because it is a consumable.
Code Er12 on other Noritz series
The same code number can mean something different on another series — make sure you're reading the page for your exact unit:
Don't confuse this with
2 other Noritz NRCP codes point at flame detection too. They are different components in different places, and ordering a part against the wrong one is the most common way this fault gets expensive: