H23

Indoor Heat Exchanger Temperature Sensor Abnormality

Home Appliance Error Codes Panasonic Split AC

Can you still use it? With care until repaired

Who can fix it? Needs a technician

Typical repair time 30 minutes – 3 hours

Typical cost SAR 80 to 1,200

What it means

This code appears on Panasonic inverter split air conditioners when the fault history is read with the CHECK button. It means the board reads an impossible value from the indoor heat exchanger (coil) temperature sensor, which points to an open or shorted circuit; this sensor protects the indoor coil from freezing in cooling and from overheating in heating. Without this reading the unit cannot run its freeze protection, so it usually stops until the fault is repaired. The same number can mean a different fault on other brands.

Models covered: Panasonic residential inverter split air conditioners (wall mounted); the code is read with the CHECK button on the remote control.

Symptoms4

A lamp blinks on the indoor unit and cooling stops or weakens.
The unit runs and then stops shortly after starting.
The unit does not respond properly to changes in the set temperature.
The code returns after a restart.

Possible causes5

A loose or unplugged indoor heat exchanger (coil) temperature sensor connector on the board.
A failed indoor heat exchanger (coil) temperature sensor whose resistance no longer matches the manufacturer table.
A cut or chafed sensor wire from heat, rubbing or rodents.
Corrosion at the sensor or its connector from constant condensation on the coil.
A fault in the sensor input circuit on the board (less common).

How to diagnose5

Switch the unit off at the breaker for a few minutes, restart it and see whether the code returns.
With power off, the technician inspects the sensor clipped to the indoor coil pipe, its wire and its connector on the board.
The technician measures the sensor resistance at the current temperature and compares it with the manufacturer table.
The technician checks the wire along its length for breaks or shorts.
If the sensor and wire are good, the technician checks the input circuit on the board.

How to fix5

Restart the unit after a power-off; a one-off glitch may clear.
Reseat the sensor connector and clean its pins.
Repair or replace a damaged sensor wire.
Replace the indoor heat exchanger (coil) temperature sensor with a part that matches the model.
Repair or replace the board if the input circuit is faulty, then run the unit and confirm the code does not return.

Repair cost

0–200

200–600

600–1,500

1,500+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost stays low when reseating the connector or replacing the sensor fixes it, and rises when the board has to be replaced.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions

What is the difference between H23 and H99?

H23 means the coil sensor itself or its circuit is faulty. H99 means the sensor works and has detected a coil that is too cold.

Can I replace the sensor myself?

It is better done by a technician, because the sensor must sit correctly in its holder on the coil pipe and the correct part for the model must be used.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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