33
Moderate
Rinnai · Tankless Water Heaters
Heat exchanger outgoing temperature sensor fault.
Quick Answer
Error code 33 on your Rinnai Tankless Water Heaters means: Heat exchanger outgoing temperature sensor fault.. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Inspect and reseat sensor connectors.
2
Check sensor resistance values.
3
Flush unit if scale buildup is present.
4
Replace faulty sensor component.
5
Verify stable operation after repair.
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
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