Noritz Error Code 29: Condensate Drain Problem (Meaning, Causes, Fixes)

What the code means

Condensing tankless heaters use the hot exhaust to pre-heat incoming water in a secondary heat exchanger, and that cools the exhaust enough for water to condense out of it. Noritz says that condensate is acidic (pH about 2 to 3) and can come out at up to about 2 gallons an hour, so it has to drain away freely. The condensate has no pressure behind it: it relies on gravity to run out of the unit, through the drain line and to the floor drain or other drain point. Noritz's knowledge base says error code 29 indicates a problem draining that condensate. Noritz's installation rules for the drain line are that it be plastic, no smaller than 1/2 inch inside diameter, as short and direct as possible, sloped toward the drain the whole way, and without any extra traps (the unit already has a trap inside). A line run outdoors in freezing weather can freeze, back up and cause a 29 code. Non-condensing Noritz models don't use this code.

Likely causes

• A clogged condensate drain line or a blocked drain line outlet
• A condensate line run outdoors that has frozen
• A drain line that isn't sloped downhill toward the drain the whole way, or is long and indirect
• An extra trap or loop added to the drain line (the unit already has an internal trap)
• A drain line smaller than 1/2 inch inside diameter
• A condensate neutralizer whose media is clogged or overdue for replacement

Safe DIY checks

1. Follow the condensate drain line from the bottom of the water heater to where it ends and check that it isn't kinked, crushed, clogged or blocked at the outlet. Noritz's owner's guide lists blockage at the condensate drain discharge as a routine check.
2. If the line runs outside and it has been below freezing, suspect a frozen line. Let it thaw, then reroute it to somewhere that won't freeze or protect it from freezing, as Noritz recommends.
3. Make sure the line slopes downhill the whole way and has no extra trap or loop. Condensate drains by gravity only.
4. If you have an external condensate neutralizer, check whether its media is clogged or due for replacement; Noritz says to follow the neutralizer's own instructions for replacement intervals.
5. With the line clear, run hot water and confirm condensate drips out of the end of the drain line. Noritz says condensate normally starts within about 15 minutes of use, though it can take longer depending on season and conditions.
6. Don't plug or cap the drain line, and don't drink or reuse the condensate; it's acidic.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• 11 Noritz Tankless Water Heater 11
• 12 Noritz Tankless Water Heater 12
• 90 Noritz Tankless Water Heater 90
• E012 / 012 / 012E Navien Tankless Water Heater E012 / 012 / 012E
• E109 / 109 / 109E Navien Tankless Water Heater E109 / 109 / 109E

All Noritz codes →

Sources

1. Noritz Knowledge Base: Error Code 29 (problem draining condensate, high-efficiency condensing models only, gravity drain, plastic line at least 1/2 inch ID, short and sloped, no extra traps, frozen outdoor line causes 29, neutralizer, applicable to models with PVC, CPVC or PP venting)
2. Noritz NRCR/EZ Owner's Guide: condensate is acidic (pH about 2-3, up to about 2 gal/h), do not plug the drain line, condensate trap danger, yearly inspection, check condensate drain discharge for blockage, neutralizer media replacement, technician must clean the line if no condensate appears