Display shows E08; heater may run pump but not compressor

Safety first: Turn off power at the breaker before removing panels.

• Access evaporator coil: Remove the front or side panel to expose the evaporator (air coil). Locate the coil temperature sensor clipped to the fins or tubing.
• Check sensor attachment: Ensure the sensor is firmly clipped to the coil surface and has good thermal contact.
• Inspect wiring: Follow the sensor cable back to the control board, checking for cuts, abrasions, or loose connectors. Repair or replace as needed.
• Clean coil area: Remove dirt and debris around the sensor to ensure accurate temperature measurement.
• Power up and test: Reassemble panels, restore power, and restart the heater to see if E08 clears.

If the error persists, replace the evaporator NTC sensor. If a new sensor does not resolve the issue, the main control board may require replacement by a qualified technician.