3.17.2020

Repairing My Window AC In The Philippines

Repairing My Window AC In The Philippines





I have sixteen draft posts that I have been procrastinating on. I have been busy doing other things too.

I was able to finish painting the water tower:


And I began painting our family meeting house. This building has been a collaborative effort of several of us:


I completed the twenty steel mats used for the windows. These each received to layers of primer and two layers of topcoat (quick dry enamel). The wood trim also got a coat to help prevent it from being eaten by bugs. We intend to cover the cinder blocks with natural stone.

Disclaimer: I have no idea what I am doing. Follow these procedures at your own risk.

Getting back to the focus of this article, my hopes have been dashed for my little Sharp window AC that I talked about in the Appliance guide. It has failed and proven to be sub-par.

The problems began when I noticed the UPS for the laptop tripped several times in spurts. I thought this was a problem with the power from the power company. This went on for a few weeks before the AC suddenly started blowing no cold air. I learned that the thermostat partially failing was causing it to rapidly cycle the compressor on/off and this was tripping the UPS.



While I had the AC opened up I brushed against some of the copper tubing and it began to hiss. The tubing had become heavily corroded in little more than two years:




Within just a few minutes all of the refrigerant was gone and gone.

Turns out that this Sharp AC was cheap for a reason.

This was when I realized that boxing up and keeping my old Carrier had been a great idea. It had worked for seven years before I replaced it with the Sharp. I did not fix the Carrier because it was under-powered and I wanted something a little stronger. Having been boxed up for more than two years, the Carrier was now more than nine years old.

When these window ACs stop working right most of the time it is either the thermostat or the capacitor:

old Carrier thermostat
old Carrier capacitor
I checked with the only service shop around us and they wanted 2800PHP just to recharge the refrigerant for the Sharp. They charged 1000PHP for the thermostat labor not included. So that is more than 3800PHP before they add in the charge for replacing all of the corroded copper. 

I decided I was going to try and fix the Carrier on my own. 

I bought this awesome Newstar UT-380TRH multimeter for 1000PHP:


Since I am just a layman I have no idea if this unit is really good. I just know that it worked for my purpose.

After shorting each terminal to the common in order to discharge any charge that the capacitor might still be carrying I set out to test the capacitor from the old Carrier:


You may be able to make out that the capacitor is bulging on the top and bottom. This is supposedly a telltale sign of a failing capacitor.

If you watch the video closely you can see that when I first test the compressor terminal there is no response, but when I next test the fan terminal there is a small reaction. This is consistent with the actual behavior of the unit. The compressor would not cycle on by the fan worked albeit not very well.

I have no video of it, but I did test the Carrier's thermostat and it did check out ok.

I also decided to test the Sharp capacitor:



The topmost scale measure impedance. You will see that for both the fan and compressor the needle springs toward zero impedance and then slides back to infinite impedance indicating a good capacitor.

Next I tested the Sharp's thermostat:



I turn the temperature control to the "warmest" setting which should give me on open circuit/infinite impedance and that worked as expected, but when I turn it to the coldest setting it should close the circuit and make the needle move to the right. It fails to do this indicating a failed thermostat - which I already knew.

So now it was time to purchase a new capacitor for the old Carrier.

I used the Sharp's capacitor for this illustration because it is easier to read:




The capacitor has three terminals: the fan terminal, the common terminal and the herm terminal (for hermetically sealed compressor).

The specifications are also shown on the bottom. The ratings for the capacitor are in uF (micro-farad). 

I have been warned that I need to get a new capacitor with the exact same rating as the old one. The old Carrier capacitor was 15/1.5uF, but the shop only had a 15/2uF. I took a chance that installing a capacitor with a bit more umph for the fan terminal would not be a problem.

After one week the 9+ year old carrier is running like a champ and I feel like a genius.

Make sure that when you remove these parts that you take digital photos and label wires as needed so you can be certain to wire up the new part exactly as it needs to be:


I briefly looked into eventual self repair of the Sharp but it seems far too complicated for me to mess around with it. I have not looked into it, but it may not even be legal for me to refill the refrigerant. I will be boxing the unit up and maybe cannibalizing it for parts and trade in the future.

Remember, I have no idea what I am doing and I do not recommend that anyone should ever copy anything I have talked about in this article. I am just sharing my experience out here on the fringes of civilization.

If you have a word of advice or constructive criticism I would like to here it. Thanks.


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