E822 🟡 Repair Required
Navien Error Code E822: Overcooling of the air conditioning coil (Evaporator coil).
⚠️ Your Navien air conditioner has detected that the evaporator coil is too cold, which can cause icing and system shutdown. This requires diagnosis and repair.
How to Fix Navien Code E822
- Step 1: Check and replace your air filter. A dirty air filter is the most common cause of restricted airflow.
- Step 2: Ensure that all supply and return air vents are open and not blocked by furniture or other obstructions.
- Step 3: After completing steps 1 and 2, reset the unit by turning it off and then back on at the breaker. If the error reappears, call a qualified HVAC technician.
What Does Navien Error Code E822 Mean?
The E822 error code on your Navien indicates that the evaporator coil in your air conditioning system is experiencing overcooling. This typically happens when the coil gets too cold, often leading to ice formation. This icing restricts airflow, reduces cooling efficiency, and can potentially damage the compressor if left unaddressed. The Navien system is designed to shut down to prevent further damage when this condition is detected. Think of it like your car overheating – the system is protecting itself.
Common Causes of Navien Code E822
- Refrigerant leak causing low refrigerant charge
- Restricted airflow across the evaporator coil due to a dirty air filter or blocked ductwork
- Faulty evaporator thermistor reading incorrect temperatures
- Failed or malfunctioning TXV (thermal expansion valve) causing overfeeding of refrigerant
Applicable Navien Models
Source Documentation
This error code is documented in 1 official Navien technical manual.
Navien NPF Installation & Operation ManualPage 129
ReasonOvercooling of the air conditioning coil (Evaporator coil).
ActionThis error occurs when the supply air (SA) temperature is abnormal. ● Check the status of the air conditioning coil (Evaporator coil). ● Check if the duct’s filter is clean. ● Check if the set cooling airflow is suitable for the cooling capacity.
Need a Pro to Fix Navien Code E822?
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 E822
Evaporator Thermistor
TXV (Thermal Expansion Valve)
Air Filter