My brand new AC compressor was frequently turning off. The room was not cool enough. And I learned from it.

Air conditioners suffer from a problem called "Short cycling" when the compressor frequently turns itself off. I recently bought another split type air conditioner and it had this problem from the very beginning. This post will be a big one. And I will explain from my experience and learning about warranty services, HVAC system and common Air conditioner problems.

It began when i saw a discount offer for Inverter Air conditioner. My bedroom AC was a three year old non inverter AC, and I was really happy with it. So i thought: let's buy a new one and install it in the bedroom. And use the bedroom AC in my work room.

My previous AC was moved and new one was installed. The next day, I went to my hometown to celebrate Eid so I could not test any of the two installations. When i returned, i faced problem in both of my air conditioners. The previous one started leaking water like a faucet. And the new one wasn't cooling the room enough.

I tried to find the root cause of water leak and stumbled upon the following list.

Water can leak from AC for these reasons:

If the filters are dirty:

The most common reason for a water leak. but I always clean the filters every two months, so it was the first thing to rule out.

If the AC is low on coolant:

Air conditioners use a coolant gas like refrigerators. My AC uses the more eco friendly R410A variant and requires approximately one litre of it. The outdoor unit is mounted with the outside wall, and I need to be Spiderman in order to reach there and check (which I am not). I found another (less reliable but still works) way to verify existence of gas. I turned on the AC, carefully observed the outdoor unit, once it starts buzzing (indicates running compressor and the outdoor unit fan also turns on) I checked if the AC is blowing cold air (which it was) and then checked water drain pipe for water, and there was water. So gas problem was also ruled out.

If the indoor unit is tilted:

Usually Air conditioners need to be properly levelled or very slightly tilted to the side with the drainage line. I had a level tester (aka water level), I used it to check the level and the tilt was right.

If the water drainage line is clogged:

The water drainage pipe might get clogged with continuous use and that can cause it to drip water in the room. I took the water output pipe and blowed in it (no pun intended). The idea is to look out for resistance. I blowed really hard 😋 and there was no resistance. My wife was observing if the air reaches the air conditioner and it was (if you open the cover of the AC, you will be able to feel the blow 😋)

The water drainage pipe is damaged:

if the water output hose pipe is damaged, it can leak. It was very unlikely in this case, as the AC was recently installed. The indoor unit needs to be detached from the wall bracket and the pipe needs to be checked (not a one person game). And to my surprise, I found out that it was the case. The installer pushed the indoor unit too hard in the bracket. The pipe was punctured. Some duct tape helped fix it.

So, my old AC was fixed. But the new AC was not cooling the room enough. It barely reached 26 degree. I called in warranty support, and the next day there was a technician at my door. And like any other technician in our country, he thought I did something wrong. Instead of inspecting the AC, he asked me if I set the temperature correctly. Then started counting the tiles of the room and said, the room is bigger than the AC capacity. I could not sleep the last night, so I got extremely angry, but I told him politely to come to my other room and showed him my old AC which had the same cooling capacity (18000 BTU AKA 1.5 ton) and told him it was there for two years in the same room. And if my old AC can cool the room, why a brand new AC with the same cooling capacity can't do it? The guy finally agreed and observed the AC for half an hour.The compressor was turning off after every 8-9 minute.  

By that time, I already ruled out low coolant, he verified it. He thought it's the indoor unit control circuit. He replaced it, but no luck.

He also checked if my AC was getting the right AC voltage and measured how many amps it was drawing from the mains. Which was ~5 amps with compressor on that combined with the voltage (p=VA) was 1200 watt which was fine for the particular AC (approx measurement, it can vary for other things)

He went away and came back next day with a new outdoor unit. He installed it but still the problem was there.

I was already loosing patience and the technician who already came to my home five times, was losing hope too. He took the whole unit with him to check in in the workshop. He came back after two days. Installed the AC confidently. But the problem was still there. He was shocked. He said they tested the AC for a whole day and it worked fine there. At that point, I was getting very impatient. I told him: brother please arrange a bed for me in your workshop, I want a good sleep. The guy was sorry and said he will come back the next day and if he fails, he will give me a completely new unit.

He came back the next day, went to the outside unit, and changed the condenser sensor position. Modern air conditioners have too many sensors. Condenser sensors sense overheating of the condenser and turns off the compressor if necessary. There are two mounting places for the sensor and by default, it is installed between the compressor and the condenser. The guys who installed the outdoor unit, did not keep enough room for the condenser to breath naturally. That's why even if the condenser was not that hot, the sensor was heating up.

The problem was finally fixed. And I could sleep again. But this incident taught me a lot. Here are my learnings:

1. I have grown a bad habit of sleeping in Air conditioned room and change in temperature interrupts my sleep. I need to work on it.

2. If I was not confident enough about my problem, I might have gone for the bigger AC and spend unnecessary money.

3. International BTU vs square ft. Chart does not apply for Bangladesh. We usually need double the recommended capacity.

4. In any work, consistency is the key.

I am really happy about the service from that Technician (Faruk Bhai) and his reluctant effort.

Quick Update: The Air conditioner is still bad. I had to opt-in for a replacement.