E594 🟡 Repair Required
Navien Error Code E594: Condensate Blockage
⚠️ Your Navien boiler has detected a blockage in the condensate drain line. This could lead to water damage if not addressed promptly.
How to Fix Navien Code E594
- Locate the condensate drain line and follow it to the exit point, usually a floor drain or outside
- Check for any obvious blockages or kinks in the line
- If you find a blockage, try to clear it using a wet/dry vacuum or a plumber's snake. If you're unsure, contact a professional
What Does Navien Error Code E594 Mean?
The E594 error on your Navien boiler indicates that the condensate drain line is blocked. Condensate is the byproduct of combustion, and it needs to be safely removed. When the drain line is blocked, water can back up and potentially cause damage to your boiler and surrounding areas. It's important to address this issue as soon as possible to prevent any further problems.
Common Causes of Navien Code E594
- Blockage in the condensate drain line due to mineral deposits or debris
- Kinked or crushed drain line
- Incorrectly installed or too small of a drain line
- Air in the system causing a blockage
Applicable Navien Models
Source Documentation
This error code is documented in 6 official Navien technical manuals.
NFB-H Installation & Operation ManualPage 116
ReasonAbnormal EEPROM
ActionCheck the PCB.
Navien NCB-H Installation & Operation ManualPage 130
ReasonAbnormal EEPROM
ActionContact technical support at 1-800-519-8794.
Navien NFB-H Installation & Operation ManualPage 116
ReasonAbnormal EEPROM
ActionCheck the PCB.
Navien NFC-H Installation & Operation ManualPage 127
ReasonAbnormal operation: EEPROM
ActionAlarm
Navien NHB-H Installation & Operation ManualPage 119
ReasonAbnormal EEPROM
ActionCheck the PCB.
Navien NPF Installation & Operation ManualPage 128
ReasonAbnormal EEPROM operation
ActionThis error occurs when the main controller does not operate properly. ● Turn off the furnace, turn it on again, and check if the furnace is operating properly. ● If this error occurs continuously, contact Technical Support at 1-800-519-8794.
Need a Pro to Fix Navien Code E594?
A licensed HVAC technician can diagnose and fix this issue quickly.
Find a Licensed Tech Near You →Replacement Parts for Navien Tankless Water Heater Code E594
Condensate Neutralizer OEM: N0301000000
Condensate Drain Line