Thermal Zone AC Error Codes and Troubleshooting

This air conditioning system has been provided with built in self diagnostic error codes. Please refer to the following table for error code definitions:

Thermal Zone AC Error Codes and Troubleshooting
Error CodesMalfunction Name
H4System Overload. Heating LED: 4 Flashes
H3Compressor Overload Protection. Heating LED: 3 Flashes
H5 IPM Protection. Heating LED: 5 Flashes
E1 High Pressure Protection. Running LED: 1 Flash
E2 Anti-Freezing Protection. Running LED: 2 Flashes
E4 Exhaust Protection. Running LED: 4 Flashes
E5 Over Current Protection. Running LED: 5 Flashes
E7Mode Conflict. Running LED: 7 Flashes
E6Communication Malfunction. Running LED: 6 Flashes
H1Defrost or Oil Return of Heat. Heating LED: 1 Flash
F1 Indoor Ambient Sensor Malfunction. Cooling LED: 1 Flash
F2 Indoor Tube Sensor Malfunction. Cooling LED: 2 Flashes
F3Outdoor Ambient Sensor Malfunction. Cooling LED: 3 Flashes
F4Outdoor Tube Sensor Malfunction. Cooling LED: 4 Flashes
F5Outdoor Exhaust Sensor Malfunction. Cooling LED: 5 Flashes
 H7 Failure Startup. Heating LED: 7 Flashes
HC PFC Malfunction PFC. Heating LED: 6 Flashes
HEDemagnetizing Protection for Compressor. Heating LED: 14 Flashes
F6 Frequency Drop for Overload. Cooling LED: 6 Flashes
F8 Frequency Drop for Over Current Protection. Cooling LED: 8 Flashes
F9Frequency Drop for Exhaust Protection. Cooling LED: 9 Flashes
H0Frequency Drop for Heating High Temperature Protection. Heating LED: 10 Flashes
E9Anti-Cold Protection. Running LED: 9 Flashes
F7Oil Return of Cooling. Cooling LED: 7 Flashes


Thermal Zone Mini-split Troubleshooting Guide
Thermal Zone Mini-split Troubleshooting Guide

The first step in troubleshooting is to disconnect power for 30 seconds to allow the unit to reset. If this does not rectify the problem proceed with the troubleshooting chart below.

Problem: The unit does not run.


  1. Is the power off?
  2. Is the circuit protection device tripped?
  3. Is voltage too high or low? (Tested by a professional)
  4. Is the Timer on?
  5. A 3 minute delay occurs before each compressor start.

Problem: Cooling and or Heating efficiency is not good.


  1. Is temperature setting correct?
  2. Are the inlet or outlet vents obstructed?
  3. Is the filter clean?
  4. Are windows and doors closed?
  5. Is fan set to low speed?
  6. Is there a heat source in the room?

Problem: Wireless remote control is not working.


  1. Reset unit. Disconnect main power for 30 seconds then reapply.
  2. Is it within receiving range? Is it obstructed?
  3. Replace the batteries.
  4. Is remote control damaged?

Problem: Water leaking into room.


  1. The air humidity is excessively high. Check to see if all windows and doors are closed.
  2. Call service Tech if not corrected by the above action.

Problem: Water leakage in outdoor unit.


  1. When the unit is running in Auto Defrosting mode, ice will thaw and drip into pan.
  2. When the unit is running in HEAT mode, the water adhered to the condenser coil drains into pan.

Problem: Noise from indoor unit emitted.


  1. When defrosting is started or stopped, it will make a sound. This is due to the refrigerant flow reversing directions.
  2. Normal refrigerant flowing in unit.


  1. If E7 error code occurs, see the AUTO mode section in Operators Manual on page 7 .
  2. An audible beep will be heard, when a button is pressed, if the remote control is communicating with the receiver.
Thermal Zone AC - Name and Function of each Part
Thermal Zone AC – Name and Function of each Part

Thermal Zone Air Conditioner Manual

Thermal Zone Mini-split Air Conditioning Systems PDF


Add a Comment

Your email address will not be published. Required fields are marked *