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Noritz · Tankless water heater troubleshooting

Recirculation not working or hot water slow - Noritz NRCR

What is going on

NRCR built-in recirculation does not run, runs at the wrong time, or hot water takes too long.

Likely causes

  • Recirc mode set wrong
  • Auto Learning still learning
  • Clock wrong after power outage
  • Clogged return or crossover filter
  • Air in return line
  • Crossover connector unplugged
  • On-demand (Title 24) mode needs the switch

Check in this order

  1. Check MM86 or the settings for the recirculation mode (Auto Learning, Manual Timer, On Demand, Always On, Always Off).
  2. Auto Learning runs recirc for the first 24 hours, then learns over 14 days; hot water use must last more than 10 seconds to be learned. It preheats 15 minutes before.
  3. Connect the EZ Start Plus app to set the unit clock to the phone time; check the schedule.
  4. On-demand (Title 24) mode recirculation only runs when the push button / motion sensor / switch is used.
  5. Clean the return line filter and the crossover valve filter; check crossover valve orientation and that the 'Crossover' connector is joined.
  6. Dedicated return purge air from the hot and return lines; the return line should have a shut-off, hose bibb and expansion tank.
  7. Lowest set temp with a crossover valve is 120 F. With two crossover valves, Auto Learning can misbehave, so use Manual Timer instead.
  8. Pump loop limits 1/2 in. loop 200 ft, 3/4 in. loop 500 ft.

Applies to: Noritz NRCR92 / NRCR111

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Source: Noritz NRCR Pro training (NRCR92/NRCR111, Printable V3), Recirc options, p.9-14, 29; Noritz EZ/NRCR Owner's Guide (Rev. 10-25), About the recirculation / Troubleshooting, p.13, 15-16, 30. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.