@Rickysin what is the tonnage? How old is it? Which part of India you from? What are the room dimensions? May be you are having under-tonnage
ac(either in terms of room size or multiple heat sources).
Higher than necessary tonnage is suggested when you have multiple heat sources- walls receiving heat from many sides, roof. In your case the warm air from roof could more than overwhelm an under-tonnage ac.
Lack of cooling is primarily due to three reasons-
1. Lack of gas in the system- leakage, non vacuuming, corrosion.
2. Under tonnage- compressor struggling to remove the heat, hence the warm air coming back to evaporator, hence less cool air.
3. Compressor out in the open- it gets heat from both the sun and trying to cool your room. If it's too hot, it will start throttling just like what happens to processors in
laptops, mobiles.
Since your machine is not able to reach the set temperature so the compressor will never step-down to reduce the speed and hence that high pitched
noise.
Less gas-
Can you access your ODU? If yes, get a MECO clamp meter (I got this
Meco 27-auto Digital Clamp Meter, Red: Amazon.in: Industrial & Scientific)
and see the ampere reading. I am assuming you have 1.5 ton so it should be 7A, 800gms refrigerant under full load. If your ac on the meter shows less than 7A, then it indicates less gas in system. The more the difference, the lesser the gas.
Less gas could be due to non-vacuuming(hence gas escapes during installation. So you end up with less than 800 gms of refrigerant for 1.5 ton) or leakage somewhere. It's better to call their technician and let them deal with it. Refer YT on how to get ampere reading for AC. Very simple.
Under tonnage- nothing can be done here.
Compressor over heating- Try to give some shade. Have some plants nearby compressor so that it can suck in cool air from the side and the rear and hence perform an effective heat exchange.
You can also look for this, I was about to purchase this as it protects from heat and rain.
Guru Dust Proof/Water Proof Air Condition Outdoor Protection Cover with Length Adjustable Hooks | Color: Silver (1.5 Ton (48x24.5 Inches x6mm)) :
Amazon.in: Home & Kitchen
www.amazon.in
So what is the point of vacuuming?
Vacuuming as the name suggests is to remove all the impurities present in the system to ensure maximum cooling and long life.
I will give an example of automobile. The fuel pipe running from fuel tank to engine should have only and only fuel, no impurities. If impurities exist, then there is issue with engine. But it has an exhaust system wherein impurities can be discarded from the engine to ensure smooth functioning.
Coming to AC, the system should have only oil and refrigerant in the system for effective heat exchange. As you know, air has lots of impurities(oxygen, nitrogen, water vapour, gases, pollutants, dust etc). So vacuuming is needed to remove these impurities from the system. If no vacuuming done, then these impurities, after several compression-expansion cycles in the compressor, start reacting with oil and refrigerant in the system forming grease-like paste within the pipe. This paste not only allows incomplete heat transfer, but also starts to corrode the pipe from the inside leading to gas leakage, poor heat exchange and hence less cooling. Also, AC's are closed system, meaning there is no provision to throw out those impurities, hence they keep cycling in the system. That is why vacuuming is done during installation prior to running the AC or during gas topup.
Some companies are very strict with vacuuming. Mitsubishi clearly states warranty is void if no vacuuming done.
What is the recent trend- installation guys instead of vacuuming use the refrigerant to purge the air. While this works, it is at the cost of gas, meaning because of this your system now has less gas even before using the ac. So if you system came with 800 gms gas, due to this you could be running 200-300-400 gms less(don't know exact figure, need research). Less gas means less cooling. Also common sense dictates that a vacuuming process which takes atleast 30 mins cannot give same result as the above which is like a 1-2 second process.
We Indians as usual are very lazy and that includes these technicians too. Since they have to carry vacuum motor pump, they will make lot of excuses ki Sir zarori nahi hai, modern machine mein nahi chahiye blah blah. If you go through any AC manual(
LG since you have it), it is clearly mentioned in the steps to install ac.
To put it crudely, vacuuming is like a bacteria- very small, innocent from the outside. Once inside the system, it wreaks havoc.
My
Hitachi 1.2 ton went bad primarily due to lack of vacuuming(pipes corroded from inside and outside).
I had almost opted for
Voltas as suggested by igloo and
Mikrotik, but it doesn't have any protection for corrosion for IDU. And this is a must coz water droplets form inside the machine and causes corrosion. Offourse, its area specific too. Northern India have dry weather so corrosion is less of issue, in my case it is a deal breaker. So went for LG.
I hope this post helps you and others. Being well-informed ensures those technicians don't give bullshit reasons when they come to rectify your issue. LG support is very good so you can raise tickets multiple times until you get resolution. Option to raise it with CEO too.. that seriously scares the shi+ out of those technicians(personal experience).