Daikin AGZ Fault Code E21
Daikin AGZ Fault Code E21 is a warning alarm indicating: Evaporator coil temperature low. The most common causes include Evaporator coil frosting. Estimated repair time: 1-2 hours. This alarm requires immediate attention by a certified HVAC technician.
Alarm Description
Evaporator coil temperature low
Brand: Daikin | Model: AGZ (Modular Scroll Chiller) | Code: E21 | Severity: Warning
Observable Symptoms
- Oil sight glass shows low level or empty
- Compressor may make unusual noise from lack of lubrication
- Oil pressure differential alarm may also be active
What to Check First
Before diving into detailed diagnostics, start with this quick first check:
Probable Causes
- Evaporator coil frosting
- Low airflow across evaporator
- Expansion valve overfeeding
- Setpoint too low
Recommended Inspection Steps
- Check evaporator airflow
- Inspect expansion valve superheat
- Raise setpoint if too low
- Defrost evaporator if iced
Required Tools & Equipment
- Coil cleaning brush and coil cleaner
- Infrared thermometer or calibrated temperature probe
- Oil level sight glass inspection tool
- PT chart for refrigerant type
- Safety PPE (gloves, safety glasses, face shield)
Estimated Repair Time
1-2 hours
When to Call a Professional
- If the fault persists after completing all recommended inspection steps
- If you observe unusual noises, vibrations, or oil leaks from the compressor
- If refrigerant charge levels are outside OEM specifications and EPA-certified recovery is needed
- If electrical measurements show voltage imbalance greater than 2% between phases
- If the fault recurs immediately after reset, indicating an unresolved safety condition
- Contact an authorized Daikin service representative for warranty-covered repairs
Related Fault Codes
Other Daikin AGZ codes that may be related:
OEM Service Manual Reference
OEM Reference: Daikin AGZ Modular Scroll Chiller Service Manual. Available through Daikin Applied technical support.
Frequently Asked Questions
What does Daikin AGZ fault code E21 mean?
Fault code E21 on a Daikin AGZ chiller indicates: Evaporator coil temperature low. This is a warning alarm that requires diagnostic attention.
What causes Daikin AGZ alarm code E21?
Common causes include: Evaporator coil frosting; Low airflow across evaporator; Expansion valve overfeeding
How do I fix Daikin AGZ error code E21?
Follow the recommended inspection steps below. Start with the quick check, then proceed through each step. If the fault persists after all steps, contact an authorized Daikin service representative.