Noritz · Tankless water heater

MM32 Maintenance monitor 32 - heat exchanger water temperature

Menu / mode display Noritz EZNoritz NRCRNoritz CDVNoritz NRC/NRCP

What the display is showing

Shows the heat exchanger water temperature. Comparing it with MM31 separates a bypass servo problem (MM32 high, outlet low) from a burner or gas problem (both low).

Applies to: EZ, NRCR, CDV, NRC/NRCP

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

12 models in Noritz EZ, Noritz NRCR, Noritz CDV, Noritz NRC/NRCP

EZ111DVEZ71DVEZ98DVN-0841MCN-0841MC-DVN-0842MCN-0842MC-DVNCC199CDVNRC111-DVNRC111-SVNRCR111DVNRCR92DV

Other codes on the same units

F76 Multi-system communication error
MM14 Maintenance monitor 14 - flow rate
MM30 Maintenance monitor 30 - inlet water temperature
MM31 Maintenance monitor 31 - outlet water temperature
MM49 Maintenance monitor 49 - fan speed
MM86 Maintenance monitor 86 - recirculation mode
BURNER ON indicator Remote burner-on indicator
Blue/Red backlight Panel backlight colour

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Source: Noritz EZ/NRCR/CDV Level 2 (Premix R2 V2), Maintenance Monitors, p.18-21; Noritz Residential Level 2 (NRC/NRCP and older, R2 V1), Maintenance Monitors, p.12-14. 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.