HVACopediaNoritz · Tankless water heater
29 Condensate collector water level abnormal
What the control is telling you
Condensate is backing up in the condensate collector of a non-premix condensing unit (NRC/NRCP). The deck only covers the drain line routing.
Applies to: Noritz NRC/NRCP and older non-premix condensing units
Likely causes
- Drain line smaller than 1/2 in., too long or with flat horizontal runs
- Drain line pitched up after a horizontal section, or a trap formed in the line
- Valves added to the drain line, or no air gap at the end
- Blocked or frozen drain line or failed condensate pump
Test and repair steps
- Check the condensate line at least 1/2 in., short and direct.
- Any horizontal run must slope down away from the unit (1/4 in. per foot); never pitch it back up.
- Remove any valves from the drain line and make sure the end has an air gap.
- If a condensate pump is used, check the pump and its 3/8 in. ID tubing.
- Clear blockages or ice from the line and confirm condensate flows.
Settings for these units
- Indoor clearances (required and recommended) · Noritz NRCR
- Operation panel menu settings and defaults · Noritz EZ, Noritz NRCR
- Water quality limits · Noritz EZ, Noritz NRCR
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Source: Noritz Residential Level 2 Maintenance & Troubleshooting (NRC/NRCP and older, R2 V1), 29 error code, p.8. Summarized in our own words; check the original manual for your model.
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