Why is my air conditioner making sounds?

[Shervan360]

TL;DR Summary

air conditioner strange sound

Hello,

I bought an air conditioner 24000 btu Inverter. ( for home). The indoor unit makes strange noises/sounds at night.

The pattern is as follows:
First, wind blowing and cooling are reduced to 80%. (Similar to fan mode)
After some minutes(About 3-4 minutes),
Then the sound (sound in the video) comes a few times and then everything returns to normal.
Wind blowing and cooling will be normal and will not be a problem.
No sound comes out of the outdoor unit.
Please watch the video.
thank you
https://youtu.be/Cj0R5KeF8m4

 

[Tom.G]

I can not say for sure but, the sound reminds me of vapor or gas bubbles in a fluid.

Maybe have the unit checked for a low amount of refrigerant or contamination / moisture in the system.

Please let us know what the fix is, we like to learn too!

Cheers,
Tom

 

[Shervan360]

I can not say for sure but, the sound reminds me of vapor or gas bubbles in a fluid.

Maybe have the unit checked for a low amount of refrigerant or contamination / moisture in the system.

Please let us know what the fix is, we like to learn too!

Cheers,
Tom

Thank you,
With the pressure gauge we checked the Gas and refrigerant is normal.
How can I know if there is moisture or air in system?

 

[Tom.G]

How can I know if there is moisture or air in system?

Moisture is the easy one, It generally freezes, the ice blocks refrigerant circulation, the system stops moving thermal energy. It can also overload the compressor causing it to shut down.

As for air, it has moisture in it which leads to blockage as above. That's why, when the coolant loop is opened, and also at initial installation, a vacuum pump is first used to evacuate the system before refrigerant is introduced. In both cases, a fresh dessicant is installed to absorb any remaining moisture.

OK, enough general background.

Household refrigerators often make similiar noises. I've gotten so used to them that I don't 'hear' them any more. If I recall correctly, the sound occurs shortly after the compressor shuts off... probably just some refrigerant boiling as the pressure equalizes on the High and Low pressure side of the compressor. Doesn't seem to be a problem for the refrigerator.

Since you seem to have a Heat Pump system that handles both heating and cooling, it could be a small leak in one of the change-over valves that switches between the heating and cooling cycles.

Unless it noticably progresses, my suggestion is 'Don't worry about it for now, but if it gets noticeably worse, have (a different) heat pump specialist look at it.'

Cheers,
Tom

 

[Shervan360]

Moisture is the easy one, It generally freezes, the ice blocks refrigerant circulation, the system stops moving thermal energy. It can also overload the compressor causing it to shut down.

As for air, it has moisture in it which leads to blockage as above. That's why, when the coolant loop is opened, and also at initial installation, a vacuum pump is first used to evacuate the system before refrigerant is introduced. In both cases, a fresh dessicant is installed to absorb any remaining moisture.

OK, enough general background.

Household refrigerators often make similiar noises. I've gotten so used to them that I don't 'hear' them any more. If I recall correctly, the sound occurs shortly after the compressor shuts off... probably just some refrigerant boiling as the pressure equalizes on the High and Low pressure side of the compressor. Doesn't seem to be a problem for the refrigerator.

Since you seem to have a Heat Pump system that handles both heating and cooling, it could be a small leak in one of the change-over valves that switches between the heating and cooling cycles.

Unless it noticably progresses, my suggestion is 'Don't worry about it for now, but if it gets noticeably worse, have (a different) heat pump specialist look at it.'

Cheers,
Tom

I greatly appreciate your time. Unfortunately, the installer didn't use a vacuum pump.

 

[Averagesupernova]

I greatly appreciate your time. Unfortunately, the installer didn't use a vacuum pump.

Then you are guaranteed the system will fail.

 

[Lnewqban]

The pattern is as follows:
First, wind blowing and cooling are reduced to 80%. (Similar to fan mode)
After some minutes(About 3-4 minutes),
Then the sound (sound in the video) comes a few times and then everything returns to normal.
Wind blowing and cooling will be normal and will not be a problem.

Could you explain the text in bold fonts a little further?

 

[Shervan360]

Could you explain the text in bold fonts a little further?

wind blowing = airflow speed/Fan speed

 

[Shervan360]

Then you are guaranteed the system will fail.

Do you think I should do a vacuum now? Of course, we have to empty all the gas and refill it.

 

[Averagesupernova]

Do you think I should do a vacuum now? Of course, we have to empty all the gas and refill it.

I am assuming you would take on this job of evacuating the system and refilling?

 

[Lnewqban]

wind blowing = airflow speed/Fan speed

I understand.
But what I was trying to ask was about the pattern that you have described:
1)Why the wind blowing and cooling are reduced to 80% at first?
2)How many times after 3-4 minutes) the sound (sound in the video) comes before all returns to normal.
3) Will wind blowing and cooling will be normal, and will not be a problem, at 80% airflow, or at 100%, or other?
Thanks.

 

[Shervan360]

I understand.
But what I was trying to ask was about the pattern that you have described:
1)Why the wind blowing and cooling are reduced to 80% at first?
2)How many times after 3-4 minutes) the sound (sound in the video) comes before all returns to normal.
3) Will wind blowing and cooling will be normal, and will not be a problem, at 80% airflow, or at 100%, or other?
Thanks.

1) I don't know. (Some people say that inverter ACs are like this.)
2) 3-4 times.
3) at 100% airflow and cooling.

 

[Lnewqban]

Again, thanks.
Do you know if an additional condensate pump has been installed inside the indoor unit?
Do you have more than one indoor unit in the same system?

https://www.greecomfort.com/assets/documents/archive/multi-revision-a/installation-manual.pdf
I have found this installation manual for your model, which indicates that:

"This unit has onboard diagnostics. Informational and error codes will be displayed on the LED display on the front panel of the indoor unit in place of the temperature display. The unit will provide informational codes to alert the user of special system operations. Informational codes are not signs of system malfunctions or failures. The following is a list of system informational codes and descriptions."

It also specifies a vacuum procedure prior to liberate the refrigerant factory charge contained in the condenser (outdoor) unit:

"The deep vacuum method requires a vacuum pump capable of pulling a vacuum of 500 microns and a vacuum gauge capable of accurately measuring this vacuum depth. The deep vacuum method is the most positive way of assuring a system is free of air and liquid water."

 

[Shervan360]

Again, thanks.
Do you know if an additional condensate pump has been installed inside the indoor unit?
Do you have more than one indoor unit in the same system?

https://www.greecomfort.com/assets/documents/archive/multi-revision-a/installation-manual.pdf
I have found this installation manual for your model, which indicates that:

"This unit has onboard diagnostics. Informational and error codes will be displayed on the LED display on the front panel of the indoor unit in place of the temperature display. The unit will provide informational codes to alert the user of special system operations. Informational codes are not signs of system malfunctions or failures. The following is a list of system informational codes and descriptions."

It also specifies a vacuum procedure prior to liberate the refrigerant factory charge contained in the condenser (outdoor) unit:

"The deep vacuum method requires a vacuum pump capable of pulling a vacuum of 500 microns and a vacuum gauge capable of accurately measuring this vacuum depth. The deep vacuum method is the most positive way of assuring a system is free of air and liquid water."

Thank you,

Do you know if an additional condensate pump has been installed inside the indoor unit?

I don't know, but I attached AC technical specifications. (PDF file)

Do you have more than one indoor unit in the same system?

One indoor unit.

Your link is not the manual of the AC, but I do not have any errors on the LED display.

 

[Lnewqban]

You are welcome.
The pump is an additional item that is sometimes installed inside the indoor unit by the installer in cases where natural drain of the condensate (water generated during cooling) is difficult to achieve.
Those are sometimes noisy when cycling.

 

[Shervan360]

You are welcome.
The pump is an additional item that is sometimes installed inside the indoor unit by the installer in cases where natural drain of the condensate (water generated during cooling) is difficult to achieve.
Those are sometimes noisy when cycling.

No, It is not installed.

 

[Lnewqban]

No, It is not installed.

Then, the noise could have two sources:
1) Air bubbles and humidity in refrigerant, as explained by @Tom.G above.
2) Mechanism moving the vent based on changes of the percentage of airflow.

I would not worry much about it, unless it interferes with your sleeping time.
Best!