Haier F28 error code, a compressor position detection fault

What does the Haier F28 error code mean?

Every inverter compressor contains a spinning rotor surrounded by fixed windings. To spin the rotor smoothly, the outdoor board must energise those windings in the right order at the right instant. Doing that well depends on knowing exactly where the rotor is.

The Haier F28 error code means the board could not work out that position reliably. Haier service information for Australian wall split systems lists F28 as a compressor position detection error. The outdoor LED1 light flashes 19 times when this fault is active.

Other Haier documents describe it as a fault in the position detection circuit. Some call it incorrect positioning of the rotor. All of these descriptions point to the same idea. The board and the rotor have lost their shared sense of place.

Why does position matter so much?

Think of pushing a child on a swing. If you push at the right moment, the swing climbs smoothly. Push at the wrong moment and you fight the motion instead.

A compressor motor works the same way. Each pulse from the drive must arrive just as the rotor reaches the right spot. When the board does not know where that spot is, the pulses arrive at random and the motor cannot run.

How does the board find the rotor position?

Most inverter compressors in split systems do not have a separate position sensor inside. Fitting one would add cost and another part that could fail in a hot, oily environment. Instead, the board reads clues from the windings themselves.

As the rotor spins, it generates a small voltage back into the windings. The board measures that returning signal and calculates where the rotor must be. This approach is called sensorless control, and it is common across inverter equipment.

There is a catch, though. At standstill, the rotor produces no returning signal at all. So the board uses a special start up routine. It nudges the rotor into a known position before speeding up.

What happens during start up?

First, the board applies a controlled current to line the rotor up. Then it ramps the speed gently while it waits for the feedback signal to become strong enough. Once the signal is clear, the board switches to normal sensorless running.

If the feedback never appears, or appears garbled, the board cannot complete this handover. That is why F28 most often shows up within moments of the compressor trying to start.

When does F28 usually appear?

The timing of the code offers a strong hint about its cause. Owners are often the only ones who see that timing, so it is worth paying attention.

• Right at start up, with the compressor humming then stopping.
• After the system has been switched off for a long period.
• On cold mornings when the system has sat unused overnight.
• Shortly after a storm, blackout or electrical work.
• Randomly during running, which is less common for this code.

A fault at start up points towards the start routine, the windings or liquid inside the compressor. A fault during running points more towards the board or an intermittent connection. Either way, record what you saw before calling.

What causes the Haier F28 error code?

F28 sits where electronics and mechanics meet, so causes come from both sides. Here is a summary before each one is explained.

The detection circuit on the outdoor board

The board contains a measuring circuit that reads the feedback from the windings. Surges, moisture and heat can damage that circuit. When it fails, the board receives poor information even though the compressor is fine.

Loose or damaged terminals

The three compressor wires connect at a terminal block on top of the compressor. Vibration and heat cycles can loosen them over time. A poor connection distorts the feedback signal and confuses the board.

Burnt terminals also tell a story. They show that heat built up at the joint, often because the connection was weak for a while. Replacing the damaged terminals and wiring is essential before testing further.

Winding damage

If one winding has partly failed, the feedback becomes uneven. The board then sees a signal that does not match any sensible rotor position. Winding damage usually means the compressor needs replacing.

Liquid in the compressor

After a long idle period in cool weather, refrigerant can settle as liquid inside the compressor. At start up, the compressor then has to push liquid rather than gas. That heavy load can stop the rotor from following the start routine.

This cause is more likely when the charge is too high or the system sits unused for weeks. A technician will review the charge if the fault keeps happening on cold starts.

A stiff or seized compressor

Wear inside the compressor can make the rotor hard to turn. In that case, the start routine applies current but the rotor barely moves. Without movement, no feedback appears, so the board reports F28.

What should you do when F28 appears?

Owners cannot repair any part of this fault. Still, a calm first response protects the system and gives the technician better information. Try the following once.

1. Switch the system off using the remote.
2. Note the time, the outside temperature and how long the unit had been off before this start.
3. Switch off the air conditioning circuit at the switchboard and leave it off for several minutes.
4. Restore power and wait a few minutes before starting again.
5. Stand near the outdoor unit and listen during the next start.
6. If you hear a hum followed by silence and F28 returns, switch off and book a technician.

Avoid repeated attempts to start the system. Each attempt pushes current through a motor that is not turning, which adds heat and stress. One reset is enough to rule out a passing glitch.

How does a technician diagnose F28?

A technician works from safe electrical checks towards mechanical ones. The goal is to find out whether the compressor or the board is at fault before ordering parts. A sound process looks like this.

1. Confirm the indoor code and count 19 flashes on the outdoor LED1.
2. Isolate power and allow the board capacitors to discharge, then confirm with a meter.
3. Inspect the compressor terminals for looseness, discolouration or melting.
4. Measure each winding resistance and compare the three readings.
5. Test the windings for insulation leakage to the compressor body.
6. Check the system charge and the crankcase conditions if cold starts are involved.
7. Observe a start attempt with suitable meters to see whether the rotor turns.
8. Test or replace the outdoor board only once the compressor checks out.

What does a clean compressor result tell us?

If the windings read evenly, show no leakage and the compressor turns, the motor is probably healthy. Attention then moves to the board and its detection circuit. This is often the better outcome, because a board swap is less involved than a compressor change.

Why test insulation as well as resistance?

A winding can show the right resistance yet still leak current to the metal shell. That leakage distorts the feedback and can trip safety devices. An insulation test catches this hidden fault, so it is a standard part of any careful compressor check.

What does a failed compressor result tell us?

Uneven windings, leakage or a seized rotor confirm a compressor problem. In that case, the board may be fine, although some technicians check it carefully too. A failed compressor can occasionally damage the drive on its way out.

What repairs are involved?

The repair depends on which side of the fault is to blame. Typical outcomes include the following.

• Replacing burnt terminals and the leads to the drive board.
• Correcting an overcharged system and checking for the reason it happened.
• Replacing the outdoor board when its detection circuit has failed.
• Replacing the compressor when windings or mechanics have failed.

Compressor replacement involves recovering refrigerant, brazing, pressure testing, evacuating and recharging. In Australia, that work needs a licensed refrigeration technician. Because of the size of the job, it is sensible to ask about the overall condition of the system first. Our page on Haier compressor repair explains what that process involves.

Can F28 be confused with other codes?

Yes, because several codes describe a compressor that refuses to run smoothly. They often appear together in the fault history. Here is how they differ.

• F28 points to the board failing to detect the rotor position.
• F11 points to the compressor running outside its normal range, sometimes called losing synchronism.
• F27 points to the compressor being blocked.
• F2 points to the compressor drawing too much current.

A blocked compressor can easily trigger F28 as well, since a rotor that cannot turn produces no feedback. Therefore, a technician reads the complete history rather than acting on one code alone. The Haier F27 error code guide covers the blocked compressor fault in more detail.

Does cold weather affect F28?

Cold weather can play a part through liquid refrigerant. When the outdoor unit sits idle in the cold, refrigerant tends to migrate to the coldest place in the system. Often that place is the compressor shell.

When you then start heating on a frosty morning, the compressor faces a heavier first load. A healthy system copes, but a marginal one may struggle through the start routine. As a result, F28 can appear more often in winter on systems with an existing weakness.

If your fault history shows F28 mostly on cold starts, mention it clearly. Then ask whether the charge is correct for your model. It is also worth asking about any standby feature that helps with cold starts. Your owner manual is also worth checking before you change how you power the unit.

What does an F28 start sound like?

Sound is one of the few clues an owner can safely gather. A healthy start usually begins with the outdoor fan, followed by a soft rising hum as the compressor speeds up. Within a short time, the sound settles into a steady drone.

During an F28 start, the pattern often changes. You may hear the fan begin, then a brief buzz or hum from the compressor with no rise in pitch. After that, everything goes quiet and the code appears indoors.

Some owners also hear a faint click as the board gives up and switches off the drive. Describe these sounds as plainly as you can when you book. They help the technician decide whether the rotor turned at all.

How can you reduce the risk of F28?

No owner habit can stop a board component from ageing. However, several steps lower the strain on the compressor and its connections.

• Keep the outdoor unit clear of leaves, plants and stored items.
• Book regular servicing so terminals, wiring and the charge are checked.
• Avoid switching the system on and off many times in quick succession.
• Have any refrigerant top up done properly, with the leak found and fixed first.
• Consider surge protection if your area often has storms.

A correct refrigerant charge deserves special mention. An overfilled system makes liquid problems at start up more likely, while a leaking one stresses the compressor in other ways. Getting the charge right protects the rotor, the windings and the drive together.

Is the F28 fault covered by warranty?

Haier offers a five year parts and labour warranty for systems professionally installed in Australian homes. A failed board or compressor within that period is generally covered under those terms. Check your paperwork for the exact conditions.

Damage from storms, poor installation or a neglected outdoor unit may not be included. When you book, have the purchase date, installer details and both model numbers ready. You can find the model number by following the steps in our Haier model number guide.

Questions to ask your technician

Asking a few good questions helps you understand the outcome and plan ahead. Most technicians are happy to explain what they found.

• Which tests did the compressor pass or fail?
• Was there any sign of heat damage at the terminals?
• Is the refrigerant charge correct for this model?
• Could the supply voltage have contributed to the fault?
• How does the age and condition of the system affect the choice of repair?

The answers help you decide whether to go ahead with a major repair. They also tell you whether anything else needs attention to stop the fault returning.

Summing up the Haier F28 error code

The Haier F28 error code means the outdoor board cannot detect where the compressor rotor sits. Without that information, the compressor cannot start or run smoothly, so the system stops. The outdoor LED1 flashes 19 times to confirm the fault.

Causes include a failed detection circuit, loose terminals, winding damage, liquid refrigerant and a stiff compressor. Try one power reset, note the timing and listen to the outdoor unit. Then leave the testing to a licensed technician, who can prove whether the board or the compressor is at fault.

Haier F28 error questions