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Noritz Tankless Water Heater Condensate Drain: Blockage Codes and Fixes

Quick Answer

Condensing Noritz water heaters (NRCP199-DV, NRCP111-DV) produce acidic condensate with a pH of 4 to 5 during normal operation. This water must drain freely through the condensate line or the unit will shut down. The most common problems are a clogged drain line from mineral or biological buildup, a frozen drain termination in cold weather, improper drain slope preventing gravity flow, and a cracked condensate trap.

Condensing Noritz water heaters (NRCP199-DV, NRCP111-DV) produce acidic condensate with a pH of 4 to 5 during normal operation. This water must drain freely through the condensate line or the unit will shut down. The most common problems are a clogged drain line from mineral or biological buildup, a frozen drain termination in cold weather, improper drain slope preventing gravity flow, and a cracked condensate trap. Clearing the blockage and restoring proper slope is usually a DIY fix. Winter freeze-related blockages may require heat tape on the drain line.

NoritzWaterheaterSeverity: moderate80% DIY Success
Time to Fix
20–60 min
Difficulty
beginner
Parts Cost
$5 – $40
Tools Needed
Flashlight, Level
Wrong code?

Not seeing CONDENSATE-DRAIN on your display?

Select what your appliance is actually doing and we'll take you to the right guide.

error code on display
HUB
heat exchanger overtemp
29
error code on display
RESET

What Does the CONDENSATE-DRAIN Code Mean?

Guide for condensate drainage issues on condensing Noritz models. Covers blocked drains, freeze prevention, slope requirements, and condensate trap maintenance.

Most Likely Causes

Based on aggregated repair data, here is the probability breakdown for this error code:

Drain line clogged with mineral or biological buildup40%
Condensate drain termination frozen in cold weather24%
Drain line installed without proper downward slope14%
Drain line kinked or pinched during installation12%
Cracked or blocked condensate trap10%

Symptoms You May Notice

  • Water dripping or pooling beneath the unit
  • Unit shutting down without a visible error code
  • Code 29 (heat exchanger high limit) triggering repeatedly
  • Visible wetness around the condensate trap or drain fitting
  • Ice at the exterior drain termination in winter

Can you reset a Noritz waterheater to clear the CONDENSATE-DRAIN code?

After clearing the condensate drain, perform a soft reset: press the power button off, wait 30 seconds, then press on. The unit should restart and fire normally. If Code 29 persists after drain is confirmed clear, the heat exchanger may have accumulated scale and needs descaling.

Tools Required for Diagnosis

FlashlightLevelBucketSlip-joint pliers

Diagnostic Checklist

Follow these steps in order. We start with the easiest external fixes before opening up the machine.

1

Locate the condensate drain outlet on the NRCP unit (typically a

Locate the condensate drain outlet on the NRCP unit (typically a small plastic fitting at the base of the unit). Trace the drain line to where it terminates.

2

Disconnect the drain line from the unit fitting

3

Inspect the condensate trap (if equipped)

4

Check the drain line slope along its entire run

5

In cold climates

Replacement Parts

If your diagnostic testing proves the component has failed, you will need a replacement. We recommend OEM parts over aftermarket for water-handling components.

Part Name
Condensate Trap / Neutralizer Kit100062581 · $15–$40
Condensate Drain Line (PVC, 3/4 in)N/A - standard PVC · $5–$15
Self-Regulating Heat Tape (6 ft)N/A - third party · $20–$35

Repair vs. Replace Calculator

Appliance Age (Years)7 Yrs
Labor Approach
Our Verdict
REPAIR
Estimated Cost: $23 (Parts) vs $1150 (New Machine)

Frequently Asked Questions

Is it normal for a Noritz water heater to drip water?
On condensing NRCP models, a small, steady drip from the condensate drain outlet is completely normal during operation. The unit extracts moisture from flue gases as part of the condensing process. Dripping from the pressure relief valve, gas connections, or water supply fittings is not normal and requires immediate attention.
How often should I flush the condensate drain on my Noritz?
Flush the condensate drain line with warm water once a year as part of your annual service. In hard water areas, flush every 6 months to prevent mineral buildup inside the line.
Can I route the Noritz condensate drain into my floor drain?
Yes, but Noritz recommends using a condensate neutralizer kit if the floor drain is connected to a metal pipe or septic system, since the condensate is acidic (pH 4-5). Neutralizer media raises the pH to near-neutral before discharge.
Does condensate drain blockage cause Code 29 on a Noritz?
Yes, indirectly. On NRCP condensing models, a blocked condensate drain can cause water to back up inside the heat exchanger area, reducing flow and thermal transfer. This can trigger the Code 29 high-limit fault. Clearing the drain often resolves Code 29 when scale is not the cause.
Will my Noritz shut down if the condensate drain freezes?
Yes. If the drain line freezes completely, condensate cannot exit and the unit will shut down to prevent overflow damage. Thaw the line carefully with warm water. For long-term prevention, insulate the drain line where it passes through unheated spaces and add self-regulating heat tape at the exterior termination.

Related Noritz Waterheater Error Codes

Code: HUBNoritz Tankless Water Heater Error Codes: Complete NR and NRCP Series GuideCode: 29Noritz Code 29: Heat Exchanger High Limit ExceededCode: RESETHow to Reset a Noritz Tankless Water Heater and Clear Error Codes

Models Known to Experience CONDENSATE-DRAIN Errors

This repair applies to most Noritz waterheaters with this error code. Common model numbers include:

NRCP199-DV, NRCP111-DV

Last verified for technical accuracy on March 14, 2026