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Michael
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Category: Appliance
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B2200 air conditioner system whistling when AC switched on.

Customer Question

B2200 air conditioner system whistling when AC switched on. When DC is on without the AC no problem
I suspect a capacitor but which one.
the unit works and cools OK but this noise is there when it is stationery
Submitted: 11 months ago.
Category: Appliance
Expert:  Michael replied 11 months ago.

Hi , I am Tech Michael an expert in this field and I will be assisting you today. I am a Master Technician that's dedicated to giving you the best Answer possible.

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I am only credited for my time and expertise if you rate kindly.

How old is your AC unit?

Also does it sound like the whistling is coming from the fan Blower.

Thank you

Tech Michael

Customer: replied 11 months ago.
The unit is 2008the fan is not running when the sound arrives infact nouthing is running and the unit is in standby.If it is started up via the remote it works well and the sound can still be heard over the air con normal noiseIf the DC is on no noise it is only when the AC is on. I am an electrical engineer and the high pitched noise is not mechanical
no fans compressors or evaporators are running.John
Expert:  Michael replied 11 months ago.

Thank you for that information. Yes it may very well be the motor start capacitor or a relay on the control board making that sound. You will need to open this one up to be sure which part is causing this sound.

Usually The start cap near the motor is the fault, but I have heard that from electronic coils and failing relays.

Once you identify the squealing part, I can help you locate a replacement for it.

In any case, I will stick with you until this is complete.

Please rate my service kindly.

Also it is the only way I am credited for my time and expertise with you.

Once you rate, I will be notified and will add your question to my priority list so you can reach me anytime until this problem is solved.

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Thank you

Sincerely

Tech Michael

Customer: replied 11 months ago.
HiI have located the whistle. It iscomming from the internal temperature sensor board . A new one was fitted about 4 weeks ago
and the unit ran Ok. I diagnosed the fault from the flasing lights.What on this board could whistle. There must be a speaker somewhere to indicate the remote is being usedJohn
Expert:  Michael replied 11 months ago.

Hi, if the whistle is pretty loud it may be coming from a tiny peizo element used as a warning buzzer.

But this sound could really be coming from a failed coil,or a transformer etc.

If that board was just replaced then it seems it is defective and needs replacing once again. It shoudl still be fully covered under the warranty.

If not you could locate that whistling part and replace it if you have good electronic soldering skills. But I would return that board or have the tech who replaced it bring you a new one;-)

Please rate kindly at this time so I can remain with you.

Thank you John.

Tech Michael

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Customer: replied 11 months ago.
HiI know its this board as I have taken it out in the last 10 mins and fly wired it back into the system. As the unit is hanging in the air as I move it the noise moves with it.I have never used this site before and will try to rate as requestedJohn
Expert:  Michael replied 11 months ago.

Hi thanks John, that worked.

I suspect that board, but who replaced it and why?

Customer: replied 11 months ago.
HiI am a controls engineer and I am used to fault finding on large systems. The manual only has two indicator functions for fault and I had a single flashing light which suggested the internal temperature sensor as stated in the manual.I spoke to Dometic who gave me the part number and I changedThe fault went away but has just been replaced with this whistle.John
Expert:  Michael replied 11 months ago.

I see, was the whistle present as soon as you changed out the board?

Or did it develop sometime later?

Thanks John.

Tech Mike

Customer: replied 11 months ago.
MikeIt came about a week after the change The problem is I am a little deaf and my wife noticed it last week on holiday
I can hear it with my hearing aids in.Is the remote receiver electronics on this small board as I cannot see a decoder or receiver chip. It mat be the main board signaling the small board.John
Expert:  Michael replied 11 months ago.

Thanks John, yes thats possible but usually what ever board is making the sound thats the one with trouble. Also make sure you dont see that little peizo buzzer f there is one on the board. If not, Its probably just a defective board as you would be surprised how many parts I replace that defective right out of the box lol.

Tech Mike

Customer: replied 11 months ago.
HiNot sure what you mean by a pezio buzzer.Johnson
Expert:  Michael replied 11 months ago.

That would be a buzzer PBC mounted for a warning but I don't believe yours has one on the board fro that.

Yours dies have one that will chirp when you turn it on normally.

You simply have a defective new board is all.

Customer: replied 11 months ago.
Hiyes no warning sounder but it does chirp when the remote is used and the sounder is on the replaced board. I will request a replacment.Many thanks John
Expert:  Michael replied 11 months ago.

Sounds good John, let me know what happens when you replace the board again.

Thank you and have a great weekend!

Tech Michael

Customer: replied 11 months ago.
Hiboard changed but the chirper still whistles. I put my finger over the chirper and it is this that is making the noiseI took the batteries out of the remote to make sure it was not giving a signal but the problem goes onthere is only one board left in the system and that is the relay boardJohn

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