32 Moderate Moderate DIY

Rinnai Tankless Water Heater 32 — Outgoing Water Thermistor Fault

Rinnai Tankless Water Heater · Error code 32

What 32 Means

The outlet water temperature sensor is open, shorted, or reading out of range.

Symptoms

  • Code 32 instead of running
  • Erratic temperature output
  • Unit won't modulate

Common Causes

1
Failed outlet thermistor

Sensor open or shorted.

2
Loose or corroded connector

Harness at PCB or sensor not tight.

3
Damaged wiring

Pinch, rodent, or moisture damage.

4
PCB input failure

Less common — board can't read sensor.

How to Fix It

  1. Disconnect power.
  2. Locate the outgoing-water thermistor on the outlet manifold.
  3. Measure resistance and compare to the chart in the service manual.
  4. Inspect harness from sensor to PCB for damage and reseat connector.
  5. Replace thermistor if out of spec.
  6. If readings are good, replace the PCB.

Parts You May Need

If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.

Common replacement Outgoing water thermistor View on Amazon→

More Rinnai Tankless Water Heater Codes

02 02 — Power Interruption / Memory Loss 03 03 — Loss of Communication / EZConnect Issue 10 10 — Air Supply or Exhaust Blockage 11 11 — No Ignition 12 12 — Flame Failure 14 14 — Thermal Fuse / Overheat Cutoff

All Rinnai codes → All tankless water heater codes →

Verified against manufacturer documentation: rinnai.us

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician.