Aircon stops cooling after 5mins, other aircon works fine.


  #1  
Old 05-06-14, 02:27 PM
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Aircon stops cooling after 5mins, other aircon works fine.

Hi, I'm a newbie at this and really need some help.

My outside unit is connected to two aircons in my house.
The issue is that one aircon works perfectly fine.
And the other aircon blows only cold air for 5 mins, then warm air all the way.

I researched that it can be capacitor problem or low on freon.
However, if these are so, why does my other aircon works fine?

I had checked that the fan on the outside unit works well for both aircons when turned on individually.
I have also washed the filters or fins of the whole outside unit so it is not dirty.
Using a RAS-M18UAX3 Toshiba Multi air conditioner outside unit.

I suspect that the unit has:
- Rusted filter dryer that leaks.
- two compressor for my two A/C,
and the compressor for the faulty one has a faulty capacitor.

Please help.
 

Last edited by zerealis; 05-06-14 at 04:25 PM.
  #2  
Old 05-06-14, 04:35 PM
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Rust on the filter drier is not a problem. Do you see any oil residue aroud the FD? Check to see if the FB has a restriction. Temp should be no more than 3* difference on each end.
 
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Old 05-06-14, 04:41 PM
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FD? I dont see any oil residue anywhere.
I believe my compressor is faulty or with faulty capacitor.
Because from the connectors to my aircons, I can feel that the one working is cold from touch.
And the one not working is not. So this means that it is a problem from the outside unit.

And because it starts off cold at first then warm, makes me believe that the capacitor is just dying out. Or the compressor works oddly.
 
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Old 05-06-14, 05:50 PM
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Doesn't sound like a capacitor problem to me. A bad cap would effect both indoor units.
 
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Old 05-06-14, 10:06 PM
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The specs and the service info are very confusing. From what I can tell....that unit uses one compressor..... not two.

These are very sophisticated inverter type units and are beyond most DIYer's knowledge for servicing.

Link to your service manual.
Toshiba heat pumps/uploads/pdf/residential/multi/SM_RAS-M18.PDF

If you go to page 79 it gives you a diagnostic routine you can run from the remote control.
 
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Old 05-07-14, 07:01 AM
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I see, but if there is one compressor only, this means that the compressor is fine because the other A/C works.
Then what are other possible reasons?
 
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Old 05-07-14, 08:40 AM
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Your Toshiba has a self diagnostics routine. Your first step would be to try that and see if there is a trouble code.
 
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Old 05-08-14, 11:27 AM
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I had performed the check. It beeped alot on the number 13 and not the rest.
But I could not find this check code on the figure of page 79 which could show what had happened.
Could you help to take a look please?

Is it suppose to be read as hex? Then it would be 0d?

"1. Check heat exchanger sensor.
2. When heat exchanger sensor is
normal, check P.C. board."

This means my heat exchanger on my indoor unit is faulty?
Can it be easily replaced or do you know if there are cables that could have disconnected it?

Because the guy came to wash/service my aircon, so he may have either unintentionally or intentionally affected the A/C, maybe pulling a cable or something?

Thanks
 

Last edited by zerealis; 05-08-14 at 12:26 PM.
 

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