Air conditioner Maintenance Tips


Sobirvs

Well-Known Member
Veteran
living in 1bhk and the ac is not doing very good cooling. It is alright i would say. Room really isn't too big and the ac is windows 1.5T... I told the caretaker but all he did was change the filters... what else i can do? I have to have a fan ON everytime , even then there is ok cooling. This is not just me, even my gf comes at my home every now and then and she told me the same thing.THis is getting frustrating. What can I do? it's not like there is no cooling.. but just not good enough cooling. any help?
 

Crazy_Eddy

Well-Known Member
Staff member
living in 1bhk and the ac is not doing very good cooling. It is alright i would say. Room really isn't too big and the ac is windows 1.5T... I told the caretaker but all he did was change the filters... what else i can do? I have to have a fan ON everytime , even then there is ok cooling. This is not just me, even my gf comes at my home every now and then and she told me the same thing.THis is getting frustrating. What can I do? it's not like there is no cooling.. but just not good enough cooling. any help?
- Is your AC sized correctly for the room?
- If the air filters have been changed, has the heat exchanger/evaporator in the IDU (the one with all the metal fins) been cleaned out? Air has to flow through a heat exchanger for it to be cooled.
- Similarly the heat exchanger/condenser in the ODU needs to be cleaned as well.
- Have the IDU fan blades been cleaned out? The fan blades are closely packed and can cause a drastic drop in air volume if clogged.
- Is the refrigerant gas pressure within spec?
- How old is the AC? Are the high-side / low-side pressures within spec i.e. the compressor is healthy?
 

vijaycool

Well-Known Member
Adept
Well nothing to report. The same AC is running as usual went with yearly cleaning routine as in the thread. There was an issue as soon as the compressor is switched on malfunction indicator begins to blink. The AC wont cutoff even after arriving at preset temp or even switchoff in remote. Have to physically turnoff the mcb to stop the compressor running. Gave the faulty board to an renowned repair guy and even after 10 days he couldnt able to fix. Scratching the head I started to search for possible solution with the IC number on the board. Its a Toshiba AC rebranded as Carrier. Got some tips on the internet and able to find the error code and turns to be indoor fan motor faulty but its running fine. Added few drops of engine oil to the bimetallic motor bearing, viola the error code issue is solved but motor is noisy..lol. I have to change it with another one now. But as of now even after 11 years it cools like a champ. ODU is the most silent among neighbors.
 

6pack

Well-Known Member
ex-Mod
Added few drops of engine oil to the bimetallic motor bearing,

Shouldn't you grease it instead of oiling it? I learnt by accident that any motor oil is made for high temps and at high temps that motor oil becomes very light and melts away grease in bearings. I had put castrol engine oil in ceiling fan bearings and every bit of grease left came off. It was flying off the fan. Like hot drops of oil or grease. Had to waste lot of time cleaning up the bearings with WD40 to remove all the left over engine oil and dust. I replaced it with white grease and no more creaky noise or rattling.

Edit: Never mind. I think my doubts are cleared after reading this link.

https://reliabilityweb.com/articles/entry/electric_motor_bearing_greasing_basics/
 
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vijaycool

Well-Known Member
Adept
Shouldn't you grease it instead of oiling it? I learnt by accident that any motor oil is made for high temps and at high temps that motor oil becomes very light and melts away grease in bearings. I had put castrol engine oil in ceiling fan bearings and every bit of grease left came off. It was flying off the fan. Like hot drops of oil or grease. Had to waste lot of time cleaning up the bearings with WD40 to remove all the left over engine oil and dust. I replaced it with white grease and no more creaky noise or rattling.

Edit: Never mind. I think my doubts are cleared after reading this link.

https://reliabilityweb.com/articles/entry/electric_motor_bearing_greasing_basics/
Bi metallic bearing does not have ball races inside. Its just a bronze bush riveted to the frame. All bi metallic bush needs to be lubricated with oil only. Further the motor is sealed , no way to open and do repairs. Ceiling Fan usually comes with ball bearings and it needs to be greased
 

Harald

New Member
Disciple
Always put a cover on the Air Conditioner when it is cold reason, Also make sure the Air Conditioner is plugged directly to the main supply. Don't give the remote control to kids. Also clean the outdoor unit every year to remove the dirt/
 

adder

Well-Known Member
Veteran
When installing a split system insist on vacuuming for atleast 20min, if leaving in coastal area which has high humidity ask them to do it with a 2 stage pump or increase the vacuuming time to 30min with single stage pump. These steps will prevent corrosion from within and in the long term potential for when they service it later, you hear Ac exploding only in countries like ours, when you vacuum it properly there is zero chance of explosion, hell even gas leak will not happen.

The installers will say no need to vacuum for short pipe length from indoor to outdoor unit, they will use the gas within the system to purge the air in lines but doing so will decrease the efficiency of the AC.
 

nRiTeCh

Well-Known Member
Veteran
When installing a split system insist on vacuuming for atleast 20min, if leaving in coastal area which has high humidity ask them to do it with a 2 stage pump or increase the vacuuming time to 30min with single stage pump. These steps will prevent corrosion from within and in the long term potential for when they service it later, you hear Ac exploding only in countries like ours, when you vacuum it properly there is zero chance of explosion, hell even gas leak will not happen.

The installers will say no need to vacuum for short pipe length from indoor to outdoor unit, they will use the gas within the system to purge the air in lines but doing so will decrease the efficiency of the AC.
What is vacuuming of AC?
Do they use some tool for it or simply vacuum cleaner thing.
Can we do it by our self at home?
 

adder

Well-Known Member
Veteran
What is vacuuming of AC?
Do they use some tool for it or simply vacuum cleaner thing.
Can we do it by our self at home?
So the Vacuum of ac means removing all the air inside the copper tubes going from the outdoor to indoor unit. This is done to remove the moisture in the air and any other impurities. We want only the refrigerant inside the copper tubes not anything else.

We cannot do this with a regular vacuum cleaner, we need a vacuum pump which works like a air compressor that you find in for tire inflation, except that instead of blowing air it sucks air.

This vacuuming most be done when installing the AC or when refrigerant is refilled in an event of a refrigerant leak and leaking is always 99% of the time due to poor installation.
 

adventureguy

Well-Known Member
Veteran
^ ****. I never knew about this vaccuming of pipes. two days back I got annual maintainance done on my ac and they checked the cooling and said no need to refill theres enough gas
 

nRiTeCh

Well-Known Member
Veteran
So the Vacuum of ac means removing all the air inside the copper tubes going from the outdoor to indoor unit. This is done to remove the moisture in the air and any other impurities. We want only the refrigerant inside the copper tubes not anything else.

We cannot do this with a regular vacuum cleaner, we need a vacuum pump which works like a air compressor that you find in for tire inflation, except that instead of blowing air it sucks air.

This vacuuming most be done when installing the AC or when refrigerant is refilled in an event of a refrigerant leak and leaking is always 99% of the time due to poor installation.
I see...Can this be done during a gas topup?
 

adder

Well-Known Member
Veteran
I see...Can this be done during a gas topup?
Yes but you have to pump down the refrigerant, meaning gas/refrigerant stays inside the outdoor unit and not in the copper tubes and indoor unit. Then you need to vacuum the copper tube lines and top up gas if necessary, If they didn't use a vacuum pump during the first install, chances are they would have use the refrigerant inside the outdoor unit compressor to purge the air out and the AC would have been working less efficient since day 1.
 

Tejas01

Well-Known Member
Adept
When installing a split system insist on vacuuming for atleast 20min, if leaving in coastal area which has high humidity ask them to do it with a 2 stage pump or increase the vacuuming time to 30min with single stage pump. These steps will prevent corrosion from within and in the long term potential for when they service it later, you hear Ac exploding only in countries like ours, when you vacuum it properly there is zero chance of explosion, hell even gas leak will not happen.

The installers will say no need to vacuum for short pipe length from indoor to outdoor unit, they will use the gas within the system to purge the air in lines but doing so will decrease the efficiency of the AC.
^^^ This!!! Very important point. Almost every article I have read, videos watched(foreign, not Indian) mentions to vacuum before letting the gas inside or during refill incase of topups. Point is mostly, people don't know about this, nor are the installation guys keen to do so(they have to carry additions vacuum pump machine). They will give lame excuses that no need to do so as mentioned by you.
I might have seen atleast 50 odd videos on AC installation in India and barely 1-2 videos showed doing vacuum(that too in one video, the customer was himself an ITI specialist and in another one the customer and service guys were friends ).
@adder How to insist on getting an AC vacuumed? I would be getting a new AC and I am pretty sure my insistence on vacuuming to the offline dealer or the technicians is going to fall on deaf ears(I am sure even the dealer won't know what is vacuuming of ac). Does the owner's manual by any chance mention vacuuming the AC? Atleast this point can be raised while installation in case they refuse to do it.
 

adder

Well-Known Member
Veteran
Yes owners manual does mention to vacuum, atleast in the models I have. The installers will not come with a vacuum pump this is certain for new installations. You just have to insist on them getting a vacuum pump. Typically they get those only on repair calls where gas has completely leaked, in those cases they vacuum it.

Take for example in my case even authorized daikin and Mitsibushi heavy industries dealers don't get a vacuum pump. Only after you insist and refuse to pay will they show up with a vacuum pump, atleast on the next day. Infact in the terms and conditions of warranty of the Mitsibushi it clearly mentions that warranty will be avoid if no vacuum is done.
 

letmein

Well-Known Member
Adept
Stupid question - is servicing of an AC required if the AC itself is working fine and cooling as expected? The normal cleaning has been done. This is a Hitachi 1.5 T split AC.
EDIT: Around ~2+ years old.
 
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adder

Well-Known Member
Veteran
Stupid question - is servicing of an AC required if the AC itself is working fine and cooling as expected? The normal cleaning has been done. This is a Hitachi 1.5 T split AC.
No. You do not need any servicing. Couple of things you can do yourself is clean the filters, vacuum the evaportor coil (ID) and use a blower on the condensor coil(OD).
You can also use stream of water on the outdoor unit coil, making sure to not put water on the fan motor.
Also check if the insulation on the copper tubes are in good shape.

If the liquid copper line, i.e smaller diameter tube in the outdoor unit has ice or frost formation, then it means its low on refrigerant. Only then do you require a service.
 

Tejas01

Well-Known Member
Adept
@adder So I got my AC installed today. Let me give a brief idea of what happened so you understand the situation.
So LG guys called, I insisted on getting vacuum pump(hencerforth pump), initially reluctant, but he did get it.
I think that despite getting the pump, he may have not vacuumed it. Here's why.
From the videos seen on the net, I have seen the vacuum pump is operated on electric. While he did attach the pump as seen in img 1, I did not hear any noise which a machine/pump makes.
So after reading manual(img 2), I understood that he did all the steps mentioned upto 3 and even upto 4 as the gauge reads 0 pressure. He did let it pump attached to the system a good 15-20 mins after taking pic so the pressure must have dropped to -30.
What what bothers me did he really vacuum the system without connecting to electrical socket. Or is that how pump operates during installation. Because as per the manual, he seems to have done all the steps. It would be really low of anyone to get the pump and not use it since he has done all the labour of getting the machine.
Anyway to rid away my concern?
He did mention while leaving that I am the first customer he has vacuumed and he mentioned the benefits. That further raises doubts whether did he knew how to vacuum in the first place.

Also, he did not use the rubber pads beneath the feet as in img 1. He told me it is used only when machine is on hard or flat surface like marble. It seemed strange coz all installation videos I recall setup those pads. Also the manual makes no mention of these pads. He did put the pads in his bag so they are not with me.
Should I be concerned?
 

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nitin_g3

Active Member
Disciple
@adder So I got my AC installed today. Let me give a brief idea of what happened so you understand the situation.
So LG guys called, I insisted on getting vacuum pump(hencerforth pump), initially reluctant, but he did get it.
I think that despite getting the pump, he may have not vacuumed it. Here's why.
From the videos seen on the net, I have seen the vacuum pump is operated on electric. While he did attach the pump as seen in img 1, I did not hear any noise which a machine/pump makes.
So after reading manual(img 2), I understood that he did all the steps mentioned upto 3 and even upto 4 as the gauge reads 0 pressure. He did let it pump attached to the system a good 15-20 mins after taking pic so the pressure must have dropped to -30.
What what bothers me did he really vacuum the system without connecting to electrical socket. Or is that how pump operates during installation. Because as per the manual, he seems to have done all the steps. It would be really low of anyone to get the pump and not use it since he has done all the labour of getting the machine.
Anyway to rid away my concern?
He did mention while leaving that I am the first customer he has vacuumed and he mentioned the benefits. That further raises doubts whether did he knew how to vacuum in the first place.

Also, he did not use the rubber pads beneath the feet as in img 1. He told me it is used only when machine is on hard or flat surface like marble. It seemed strange coz all installation videos I recall setup those pads. Also the manual makes no mention of these pads. He did put the pads in his bag so they are not with me.
Should I be concerned?
That's why I got the installation done by local expert. He knows that if anything goes wrong I'll be on him, so he does his best while installing. I didn't even know that vacuuming is required but he did it because it was a necessary step in the process.
 

adder

Well-Known Member
Veteran
@adder
So after reading manual(img 2), I understood that he did all the steps mentioned upto 3 and even upto 4 as the gauge reads 0 pressure. He did let it pump attached to the system a good 15-20 mins after taking pic so the pressure must have dropped to -30.
What what bothers me did he really vacuum the system without connecting to electrical socket.

Also, he did not use the rubber pads beneath the feet as in img 1. .
Should I be concerned?
He didn't vacuum, since according to you he didn't connect it to a electrical socket(unless he had super expensive cordless version with battery). Instead he uses the outdoor compressor to vacuum, i.e opening only one valve in the outdoor unit.
These kind of people should be fired on the spot, literally.

Rubber pads while it helps is not that relevant in inverter AC, because they don't jerk when the compressor switches On.
A fixed speed regular AC will jerk because it rotates to its max capacity in an instant, where as a inverter AC will start slowly, can take as much as a minute to reach full speed on start up.

You can still add a piece of rubber, like cut from a car mat. loosen one bolt at a time lift the outdoor unit, insert a small piece of rubber with holes made by blade or drill for the bolt to go through. I did this in my native place, since the installation was done without me.
 

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