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Noritz 63 (recirculation abnormality): what to check

By How House Works EditorialBased on Noritz manualsChecked against sources Updated

Noritz display

63

“Recirculation abnormality (No recirculation flow)”

NRCR · NRCR Owner's Guide Rev. 04/21, p. 19; NRCR Technical Sheet FPHK081, p. 1
Owner checks, then technician

Among NRCR guides only the 2021 edition lists 63 (NRCR Owner's Guide Rev. 04/21, p. 19); the 2024 and 2025 guides give the same checks under 06 (EZ/NRCR Owner's Guide Rev. 10/25, p. 31). NRCR Technical Sheet FPHK081: “Recirculation Abnormality (No recirculation flow)”, with pump checks (p. 1). The Field Manuals list 63 as “Recirculation Pump Error” in tables that do not say which models show it (Field Manual KS-11-0004, p. 26; Field Manual June 2011, p. 34).

What it means

63 is a recirculation code on the NRCR92DV and NRCR111DV. The 2021 NRCR guide calls it “Recirculation abnormality (No recirculation flow)” NRCR Owner’s Guide Rev. 04/21, p. 19. The 01/24 and 10/25 guides do not list 63 and give the same checks under 06, “Recirculation abnormality” EZ/NRCR Owner’s Guide Rev. 01/24, p. 25; EZ/NRCR Owner’s Guide Rev. 10/25, p. 31.

Noritz’s technical sheet for the NRCR models of the 10/25 guide keeps both codes. There, 06 is a warning that the heater detects recirculation flow but not enough of it, and 63 means no recirculation flow, with checks on the pump NRCR Technical Sheet FPHK081, p. 1.

Check these first

  1. Check the return line filter and the crossover valve’s filter NRCR Owner’s Guide Rev. 04/21, p. 19. The technical sheet marks the crossover valve check for crossover mode only NRCR Technical Sheet FPHK081, p. 1.
  2. The guide’s maintenance section shows two water drain valves with filters, one in the hot water return and one in the cold water inlet NRCR Owner’s Guide Rev. 04/21, p. 16; EZ/NRCR Owner’s Guide Rev. 10/25, p. 27. To clean them, turn the heater off and let it cool; close the hot water valve, the water supply valve and the hot water return valve; remove the water drain valves over a bucket, clean each filter with a brush under running water and refit the valves without losing the O-ring; then reopen the three valves and check that the drain valves do not leak NRCR Owner’s Guide Rev. 04/21, p. 16. About 0.85 gallon (3.2 L) of water drains out NRCR Owner’s Guide Rev. 04/21, p. 16.
  3. The guide does not say whether that hot water return filter is the “return line filter” of the code table, and it does not name the crossover valve’s filter or say where it is. For other questions the code table says to contact Noritz America; the 2021 guide gives 1-866-766-7489 NRCR Owner’s Guide Rev. 04/21, pp. 19–20.
  4. On heaters covered by the 10/25 guide, press Menu and select Error History to see the eight most recent failures, “1” being the latest EZ/NRCR Owner’s Guide Rev. 10/25, p. 20.

When to call a licensed technician

  • The pump. For 63 the technician checks that the pump rotates, the pulse frequency from the pump rotational frequency sensor, the pump connection and the voltage from the circuit board NRCR Technical Sheet FPHK081, p. 1.
  • Recirculation settings and air in the lines. For 06 the sheet adds checking that the recirculation type in the unit settings is correct and, in dedicated mode, purging the air in the hot water line and return line NRCR Technical Sheet FPHK081, p. 1.
  • Related NRCR codes on the same sheet: 42, a fault of the recirculation water flow sensor, and 79, a failure of the circuit board’s pump control circuit NRCR Technical Sheet FPHK081, p. 1.

Notes for different models

  • In the 2021 NRCR guide, 06 means “Low recirculation flow” and is only a warning: the heater keeps running, and the one check listed is the return line filter NRCR Owner’s Guide Rev. 04/21, p. 19.
  • NRCP heaters use their own codes: Er:44 is “Recirculation Abnormality” on the NRCP1112 and NRCP982 NRCP1112/NRCP982 Owner’s Guide Rev. 05/19, p. 39 and “Possible pump failure” on the NRCP111 and NRCP98, which also have Er 46, “Low recirculation flow” NRCP111/NRCP98 Owner’s Guide Rev. 05/19, p. 34.
  • Field Manual KS-11-0004 (October 2012; NRC83, NRC98, NRC1111, NR981, NR83-DVC) and Field Manual June 2011 list 63 as “Recirculation Pump Error” in tables that do not say which models show it Field Manual KS-11-0004, p. 26; Field Manual June 2011, p. 34.

Related Noritz codes

  • 06 “Recirculation abnormality”
  • 42 “Water Flow Sensor (Recirculation) abnormality”
  • 79 “Circuit Board abnormality”

All Noritz codes

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Sources

  1. NORITZ America Corporation. EZ/NRCR Owner's Guide Rev. 10/25. SBB81M1, Rev. 10/25; cover title: Condensing Tankless Gas Water Heater Owner's Guide; covers EZ111DV, NRCR111DV, EZ98DV, NRCR92DV and EZ71DV (GQ-...-FF-1 US models); EZTR50 and EZTR75 are named only in the warranty table (p. 36); p. 1 is the unnumbered cover. Accessed Oct 12, 2026.
  2. NORITZ America Corporation. EZ/NRCR Owner's Guide Rev. 01/24. SBB81HC, Rev. 01/24; cover title: Condensing Tankless Gas Water Heater Owner's Guide; covers the 2024 EZ111DV, NRCR111DV, EZ98DV, NRCR92DV and EZ71DV (GQ-...-FF US models). Accessed Oct 12, 2026.
  3. NORITZ America Corporation. NRCR Owner's Guide Rev. 04/21. SBB8167-3, Rev. 04/21; covers NRCR111DV (GQ-C3260WXQ-FF US) and NRCR92DV (GQ-C2660WXQ-FF US). Accessed Oct 12, 2026.
  4. NORITZ America Corporation. NRCP1112/NRCP982 Owner's Guide Rev. 05/19. Rev. 05/19, no SB number printed; title line: NRCP1112-DV / NRCP982-DV (Eco TOUGH). Accessed Oct 12, 2026.
  5. NORITZ America Corporation. NRCP111/NRCP98 Owner's Guide Rev. 05/19. Rev. 05/19, no SB number printed; covers NRCP111-DV and NRCP98-DV (listed by Noritz as the 2019 models). Accessed Oct 12, 2026.
  6. NORITZ America Corporation. NRCR Technical Sheet FPHK081. Sheet code FPHK081, no revision or date printed; 2025 NRCR111DV and NRCR92DV (GQ-...-FF-1 US); image-only PDF; only its NRCR rows 06, 42, 63 and 79 are used on this site; a service document; no page numbers printed, p. 1 is the PDF page. Accessed Oct 12, 2026.
  7. NORITZ America Corporation. Field Manual KS-11-0004. KS-11-0004, Rev. October 2012; cover title: Gas Water Heater Field Manual (NRC83, NRC98, NRC1111/NCC1991, NR981/NC199, NR83-DVC); written for service technician training seminars. Accessed Oct 12, 2026.
  8. NORITZ America Corporation. Field Manual June 2011. Rev. June 2011; cover title: Gas Water Heater Field Manual (NR50-OD, NR66, NR71, NR98, NCC199, NRC111, NR111, NC380); a service technician training document. Accessed Oct 12, 2026.