HVACopediaNoritz · Tankless water heater
MM86 Maintenance monitor 86 - recirculation mode
What the display is showing
NRCR only. Shows which recirculation mode the unit is actually set to, which confirms the setting matches what the owner expects.
Applies to: NRCR92, NRCR111
What to do
- Open the maintenance monitor (display window, remote or EZ Start Plus app).
- Select the MM number.
- Read the value, compare with set temperature and expected behaviour.
Settings for these units
Indoor clearances (required and recommended) · Noritz NRCR
| Location | Required | Recommended (service) |
|---|---|---|
| Top | 12 in. (300 mm) | 3 in. (76 mm) above and below exhaust |
| Front | 4 in. (100 mm) | 24 in. (610 mm) |
| Sides | 3 in. (76 mm) | 8 in. (203 mm) |
Required clearances apply to both combustible and non-combustible materials.
Recommended space is for service and quick access to gas and water shut-offs.
Operation panel menu settings and defaults · Noritz EZ, Noritz NRCR
| Setting | Options | Default |
|---|---|---|
| Max Set Temperature (power off) | 100-140 F in 5 F steps; 37-48 C, 50-60 C | 120 F / 50 C |
| Recirc ON/OFF | ON / OFF | OFF |
| Recirc Mode | Always OFF, Always ON, Manual Timer, Auto Learning (NRCR) | Always OFF |
| Vacation Mode | Active / Inactive | Inactive |
| Flow Meter Alarm | 10-60 gal (5 gal steps), 70-100 gal (10 gal steps), OFF | Alarm OFF |
| Drain Water (power off) | Start / Cancel | Cancel |
| Scale Flushing (power off) | Start / Cancel | Cancel |
| Audible Alarm | ON / OFF | ON |
| Screen Lock | Active / Inactive (4-digit password) | Inactive |
| Units (first 10 min after power-up, power off) | [F/gal/ft] or [C/L/m] | [F/gal/ft] |
| Power Saving Dis. / Backlight | ON-OFF / Power Save ON-OFF | ON / Power Save ON |
| Brightness / Contrast / Touch Sound | Bright-Normal-Dim-Dark / -15 to +15 / ON-OFF | Normal / Standard / ON |
Setting 125 F (55 C) or higher needs Max Set Temperature raised first; the panel warns about scald risk.
Default Settings resets everything in Settings except Screen Lock (hold OK about 5 s).
- Water quality limits · Noritz EZ, Noritz NRCR
Models that show this code
2 models in Noritz NRCR
Other codes on the same units
- MM14 Maintenance monitor 14 - flow rate
- MM30 Maintenance monitor 30 - inlet water temperature
- MM31 Maintenance monitor 31 - outlet water temperature
- MM32 Maintenance monitor 32 - heat exchanger water temperature
- BURNER ON indicator Remote burner-on indicator
- Blue/Red backlight Panel backlight colour
- Display window Built-in display window (NRCR Pro)
- Error History Error history list
Save it for the next call
Star this code in the HVACopedia app and keep the whole library on your phone for jobs with no signal.
Source: Noritz EZ/NRCR/CDV Level 2 (Premix R2 V2), MM86 Recirculation Mode, p.21. Summarized in our own words; check the original manual for your 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.