Navien · Tankless Water Heater Moderate

E193 — Condensate Drain Blockage

The condensate trap or drain line is blocked, allowing condensate to back up inside the unit.

Keep using it?
Yes, with caution
DIY difficulty
Easy
Typical cost
$20-40
Verified against
navieninc.com ↗

The fix

Navien condensate trap / drain line kit (model-specific)

Condensate trap or drain line blocked, causing condensate backup

$20-40 moderate difficulty 30-45 min Tools: screwdriver, bucket

Diagnose first: Condensate drain-line plumbing, not the gas/combustion side — safe to inspect and clear yourself. Check the external trap and drain line for a clog or kink before replacing the trap. Repeated clogs are often a slope or venting issue worth having a plumber look at.

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How to fix it

  1. Power off the unit.
  2. Remove and flush the condensate trap with warm water.
  3. Inspect the drain line for kinks, sags, or freezing; reroute as needed.
  4. Service or replace condensate neutralizer media if installed.
  5. Verify free flow from trap to drain before restoring power.

Why it happens

Typical signs: E193 on display · Water under or inside the unit · Unit shuts down · Gurgling sound

  • Plugged condensate trap Sediment and combustion byproducts clog the trap over time.
  • Kinked or frozen condensate hose Drain line pinched or frozen in unconditioned space.
  • Plugged neutralizer Spent media or debris blocking the condensate neutralizer outlet.

Other parts sometimes needed

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

  • Condensate neutralizer media Common replacement
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More Navien tankless water heater codes

E003 E003 — Ignition Failure E003C E003C — Cascade Ignition Failure E012 E012 — False Flame / Flame Loss E016 E016 — Overheat / High-Limit Trip E027 Tankless E027 — Sensor Abnormality E030 E030 — Abnormal Exhaust Temperature (Flue Overheat)

All Navien codes → All tankless water heater codes →

Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: navieninc.com.