33 minutes ago, lopburi3 said:

You are cleaning the outside unit when you clean the inside? 

Yes I clean outside unit as I mentioned earlier. I take of the cover and spray the coils with the garden hose. By the way the outside unit is in the shade. 

Yesterday I checked the dual capacitor from the outside unit with my multimeter. I set to the 1k ohm meter and during the test the pointer didn't show much movement. So today I found a new dual capacitor somewhere in Rama 2 Road. It's a bit hard to find this item. Mostly they have the single one. And also I couldn't get the same 40/1.5 uf they had 45/1.5 uf. But in the store they told me I can use t. It was 245 baht. So I installed the new 45/1.5 uf capacitor and I see some improvement. During the hot day it blows 11 celsius temp air from the cage fan. Before it was 17 celsius. 

Normally,  the capacitor used for the compressor is to help "start" the compressor and after a few seconds which gives the compressor enough time to get up to full speed a relay takes the capacitor out of the circuit.   However, some compressors will also utilize a smaller sized "run" capacitor which is in circuit all the time but this is not the normal. 

 

The fan in compressor unit also has a "run" capacitor....when they go bad the fan will either not start or run slowly.   Like when a cap in a floor/desk/ceiling fan goes bad....the fan will start slowly and/or run slowly....take a long time to get up to full speed.

 

When testing a capacitor with an ohmmeter it should read as an open/very high resistance after a very brief period of reading low resistance, BUT, this only means the capacitor is not shorted...the capacitor could still be bad....open.   To do a better test you really need a multimeter that also measures capacitance and the cap should read plus or minus approx 10% of it rating.   And ideally a voltage breakdown tester should be used to test the cap but that is specialized/costly test equipment.   

 

Regarding cleaning of the compressor fins you should spray the water on the fins from the inside which pushes dirt/gunk back out the way it tried to come in as the fan pulls air from the outside thru the fins and then past fan.  You still need to spray the outside of the fins also, but spraying from the inside is best.