Fujitsu heat pump noise

I have found that with my Fujitsu Halcyon, it needs to be disconnected from the mains at the breaker for 2 hours to properly reset. Use that time to clean the filters in the wall unit. The clicking you hear is self testing of relays.

When was the last time that it was cleaned? Describe the noise.

That is most likely the unit overheating and trying to cool itself off. Check any filters that are on it to be sure they are clean.

does the ac continue to make the noise even in fan only mode or is only in cooling mode. If only in cooling then it could be a gas related problem or blocked coil.

If it happens in heat it must happen in cooling. The indoor unit has nothing to do with if it's heating or cooling. You likely have 2 moving parts in the machine, the blower wheel and the swing fins. Turn swing option off, eliminate that. You get the rest...

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Why does my heat pump ice up in Winter?
Heat pumps naturally ice-up in the winter. It is normal for the entire coil to be covered in a white frost and even light ice, during cold weather conditions. However, it is bad for the entire unit to be encased in ice. This indicates ductless heat pump problems which should be addressed quickly to save energy and avoid serious damage to your ductless unit. These systems should periodically go into a defrost cycle. This keeps the unit running efficiently. If the coils are blocked by ice, proper heat transfer between the coil and the outside air will not occur.
How does the defrost mode work?
When the mini split heat pump goes into defrost, the reversing valve inside of the outdoor unit is energized, switching the system from heat to the air conditioning mode. The outdoor coil becomes the hot, the indoor coil becomes cold, and both - the outdoor and indoor fans shut off. This allows the outdoor coil to melt accumulated ice. When the built-in micro-computer analyzes that all ice have been melted, the heat pump heating system goes back to heating mode.
A cloud of water vapor may be seen rising over the outdoor unit and a "whoosh" sound can be heard as the refrigerant reverses direction. The entire process usually takes up to 10 minutes (depending on conditions).
How often does the system goes into defrost mode?
Ductless mini-split heat pumps have different ways of determining when to go into defrost. The built-in microcomputer determines outdoor temperature, refrigerant pressures, and several other factors. In colder temperatures the system will go into defrost more often than in warmer.
If a ductless mini split heat pump is severely iced-up in the winter it is possible that it isn't defrosting (though there could be many other causes). Let the manufacturer certified technician check your system

I have same problem like yours to my newly installed Fujitsu multi-split system (the first time use since system installed 1 week ago). I rang the electrician who did the installation; he said it must be the units themselves nothing to do with electricity.

Okay, then I rang Fujitsu and their local service agent. They suggested me to switch off C/B for an hour to reset the units. I followed the instruction but the indoor units still did not respond to remote control...

It simply looks like no power supply to indoor units (they are hard-wired to the outdoor unit). So I used a multi-meter to test the power terminals of indoor units (Danger! If you have no idea about this, don't even try! ): it seemed no power supply even C/B is on. I turned to the isolator which next to the outdoor unit. The isolator was making arcing noise when I switched it on and off. The indoor units suddenly turned on for few minutes then died again.

So I figured out the problem is that crooked isolator. I called the unhappy electrician to replace the isolator. End story....

I hope my experience will help you a little bit.

This unit comes with a remote control (optional wall mounted wired thermostat available) as a standard feature. This unit is precharged with the environment friendly R-410a refrigerant. No additional refrigerant is needed if the line set is 49 feet in lenght or shorter. In addition to its very high 20 SEER efficiency rating, the 15RLQ is only 31 in. long which makes it the smallest Mini-Split System in its category through out the industry.
This category of equipment is ideal for smaller spaces where spot cooling is required. Several models in this category are ENERGY STAR Certified, meaning they save you money on your utility bill. Residential applications including sunrooms and additions are made easier with these air conditioners and heat pumps. Do you have a warm spot in your home? Fujitsu mini-splits can provide extra cooling capacity for those hard to cool areas. Commercially, their small size makes them ideal for small offices, providing individual temperature control.
Fujitsu's I.A.Q. Systems provide residential and commercial property owners an innovative solution for clean, temperature-controlled indoor air. The Halcyon IAQ systems deliver powerful heating and cooling, are designed for ease of use and maintenance, and feature an unobtrusive design which can be integrated easily into any decor. The Halcyon IAQ systems filter dust, pollen and odor making them the perfect addition to any home!
Standard Features

• Wireless Remote Control
• Plasma Filter
• Sleep Timer
• 24 Hour Timer
• Dry Mode
• Auto Louver: Up/Down
• Auto Mode
• Quiet Mode
• Auto Restart/Rest
• Auto Changeover
• Low Ambient
• Cold Prevention

Warranty All Fujitsu ductless mini-split air conditioners and heat pumps come with a 2 year parts and 6 year compressor warranty.
Important: All installations must be performed or supervised by a certified HVAC technician in order for the warranty to be valid.

Check the disconnect switch and make sure that both the fuses are good and not shot. If one is shot then the system wont work. There are two fuse. Also be careful due to you will be working around 210 volts

the outdoor unit is totally dead or only to the heat mode?if it is to the heat mode propably must check the refrigirator.if it is too the cool mode the plate has problem.if is multi check the outdoor plate in other occasion check the indoor plate.