[Mortis]

Originally Posted by thanixravindran

I get this wind blowing noise only when the filters are clogged in my AC (rarely if I miss my regular cleaning) and after regular cleaning, this goes away. Does this happen on all the modes? You mentioned it is not in blower but what is blower mode - Is it the fan mode you are referring or something else?

Not related to the problem, but curious what bleach you are using and how do you do the bleach wash? Can we do it ourselves or is it by AC service person?

My filters and everything else is clean. Yet the sound still comes, even if I remove the filters and keep the flap open.
Blower mode mentioned is wrt the quoted post which mentioned that some ACs have some "natural wind" type blower feature and yes blower and fan are interchangeable in this case though usually the indoor one is called the blower and outdoor one is referred to as fan due to their differences in shape and operation.

I'm using Clorox bleach diluted 50-50 and pouring it over the last couple of inches of the cooling fan to clean and unclog the drain channel. To clean the coils it's better to use a dedicated AC foam cleaner, even the car one will do

[dsr001]

Need a split AC for home with single ODU (outdoor unit) and 3 IDU (indoor units).

Any suggestions for brand and any idea what could be the cost of purchase + installation?

I tried searching online but could not get reliable info at all

[H_Dogg72]

Originally Posted by suzuki san

Hi Guys,

I am absolutely amazed reading posts here where people set the temperature to 24, 26 and even 28C. I don't know what I am doing wrong but my A.C's are always set at 20C with the fan on one setting less than full. That's the way it stays the whole night! Timer!! What's that? This is in Bombay & Goa. It's exactly the same in my car as well. 20C is my comfort zone temperature.
I am really surprised that even guys living in Kerala and Chennai are setting their room A.C's at 26 - 28C.
Is the A.C being used as a dehumidifier? If so, why not just buy a de-humidifier which is much cheaper than any A.C.
I just don't see the point or am I missing something?

Regards,
SS

Originally Posted by Gansan

When the ambient temperature is in the high thirties or forties, if you set the temperature at 20, your display will show 20 but your room will never reach 20, and the compressor will run the whole day without cutting off.

The norm is to set it 23-27 degrees to feel comfortable. Believe me, when the ambient temperature is 33 degrees, even 28 will feel comfortable.

There is no way to control the temperature of the chilled air coming out of the Ac. It will be a constant 18 c. What we are doing is setting the thermostat at a desired temperature, so the compressor cuts off when room air matches it. If we set it 12 degrees below ambient temperature, that is never going to be reached, however long the Ac runs.

Was interesting to read this discussion. It is a personal preference and this is what I get in Delhi heat in my room with an almost 15 year old Samsung Split AC. Two different temperature sensors it is for this reason I dislike how the climate control goes only to 18 in my car before low, unlike the GTI which goes to 16.

An over sized AC will get you as cold as you want.

[Ravi Parwan]

Wow, did not know we had such a long thread on Air Conditioners!

A couple of points from my side, hopefully this will answer some of the questions raised above.

An inverter AC is highly dependent on the PCB and yes, the consensus is that they go bad in 4-5 years and cost a bomb to replace. I had two Daikin ACs conk out due to PCB failure and wiped out all the perceived savings from the lower running costs over last 5 years in one go.

However, the benefit of the inverter AC is not just in the lower running costs. The beauty of the inverter AC is its adaptability. A normal AC will switch on the compressor and run full tilt towards the set temperature. Your car AC gives out air at around 4-5 degree celsius at the grill!! Similarly a window AC or a split AC will give you air at around 5-6 degree celsius (at the grill) when on full load. That air mixes with the hotter air in the room/ car to give you air of around 24-25 degrees. So you feel cold when the conditioner is running for long and hot when it is cycled off, after reaching the set temperature.

This is where the inverter AC will outshine. An inverter AC, similar to a non inverter AC will run full tilt to cool the room at 5-6 degree output initially. However, as soon as the sensor indicates that the room is nearing the desired temperature, it will reduce the compressor speed, so your AC will be giving out air at around 12-13 degree celsius. ( No AC can/ should give you air at 18- 24 degree, if it is, get it checked). Now, based on the room conditions, the AC will continue to run at between 12-16 degrees to keep the room temperature constant at the set temperature ( 25 degrees in my case).

In case you have set the AC at a much lower temperature (<20 degree) the AC will continue to run at lower grill temperature and try to cool the room. The reason for the increased energy bills in such as case are due to the constant heat loss from the room that the air conditioner is fighting against. Otherwise, the refrigerator which is a similar machine (with lower thermostat settings and different refrigerant etc) works its magic with only 100-150 W!!

I spent almost 25K on getting my Daikin ACs repaired last year. Half of it was due to a refrigerant leak as the evaporator had developed a leak. This year another 4-5 K is expected as another PCB failure is suspected. However the comfort of an inverter AC is such that I have again opted for an inverter AC from Panasonic for my home. I just hope that I don't need to use the 5 year PCB warranty on this one...

[vijaysrk]

Originally Posted by dsr001

Need a split AC for home with single ODU (outdoor unit) and 3 IDU (indoor units).

Any suggestions for brand and any idea what could be the cost of purchase + installation?

I tried searching online but could not get reliable info at all

What you need a VRV system, but do you really have a use case for it? VRV systems are good for office environments where the duty cycle of operation of the multiple IDUs tend to be high.

For homes, it might just be cheaper (initial cost wise) and easier to go for individual units.
Another issue with VRV systems is that you have a single point of failure in the form of the ODU. With multiple independent units, you have some redundancy as well, if that makes sense.

[sandeepmohan]

Originally Posted by Ravi Parwan

An inverter AC is highly dependent on the PCB and yes, the consensus is that they go bad in 4-5 years and cost a bomb to replace.

Unless a proper diagnosis is done, the general consensus will always be that Inverter AC's have a higher failure rate.

All electronics have pcb's. It will be a specific component or part on the pcb that fails. Not the entire pcb itself. Our AC technicians are not really bothered or qualified to identify what exactly has failed on the pcb. Something on the pcb packed up and the usual answer will be to change to entire pcb. If you take that same pcb to a qualified electronics technician that can do component level repair, it will be clear what is failing.

For the dealer, replacing the pcb is the easy way out to fix the problem. The customer does not have to wait too long either and we are willing to pay whatever it costs. Its business for them too.

I hope you don't run into this problem again. If you do, don't hand over the pcb to them. Identify a qualified technician and get them to diagnose the pcb board step by step.

[Ravi Parwan]

Originally Posted by sandeepmohan

For the dealer, replacing the pcb is the easy way out to fix the problem. The customer does not have to wait too long either and we are willing to pay whatever it costs. Its business for them too.
.

This is precisely what happened with me the first time around. They changed the PCB as well as the fan motor. I took that PCB to a repair person after identifying that the fan capacitor was swollen and probably faulty. Got that changed and used that PCB in the other AC. That AC is running properly so far. Touchwood

Originally Posted by sandeepmohan

I hope you don't run into this problem again. If you do, don't hand over the pcb to them. Identify a qualified technician and get them to diagnose the pcb board step by step.

Unfortunately, that has happened already. I am done with the official dealer/ service team and have asked a local electrician to help me out. still looking for a competent technician in Faridabad who can help me without breaking the bank.

[Aroy]

Originally Posted by sagarpadaki

The LG split(non inverter) is behaving weird. It is not respecting the set temperature and is cooling beyond the set temperature by a big margin. I set the temperature at 29 and the compressor stops once the room is cooled to 24 degrees(As read by the bed side thermometer). It kicks back in when the temperature rises to 28. This is causing lot of discomfort late in the night when the compressor kicks in and we are frozen to the bone!

I understand the cooling is not linear and the hysteresis is involved. But I was expecting the difference to be around 2 degrees. Not 5 degrees!

Any suggestions on how to fix this problem. Thanks in advance

The hysteresis is due to the temperature sensor. It is either dirty or has moved away from the cooling coil. If it is just hanging in the air, it will sense the air temperature and not exit temperature.

FIX
. Locate the sensor, in most AC's it is clipped on to the evaporator coil (front side for window AC).
. Clean the sensor if dirty and clip it on to the coil.

If this still does not work the either the sensor or the MB needs looking into.

[thanixravindran]

Originally Posted by sandeepmohan

All electronics have pcb's. It will be a specific component or part on the pcb that fails. Not the entire pcb itself.

Originally Posted by Ravi Parwan

I took that PCB to a repair person after identifying that the fan capacitor was swollen and probably faulty. Got that changed and used that PCB in the other AC. That AC is running properly so far.

Yes, this is true in most cases. On the AC PCBs, the IDU will have a PCB which does all the sensing and control, drain motor control, indoor fan, slat angle control all needed for Indoor operation. ODU earlier used to have PCB that takes the power line and control the motor driving the compressor as well the fan to dissipate the heat (This is the reason earlier you can interchange IDU or ODU locally. But later manufacturers have added communications with IDU for some ACs and it become a pair coded in software ).

In inverter AC, this ODU PCB has to do the power inversion for variable speed control with IGBTs (insulated Gate Bipolar Transistors) as well another micro controller controlling it. During inversion there is a quite a bit of heat produced for which dissipation needed. Heat sink is done through copper area in the PCB itself or external metal plate heat sink is provided depending on design.

So most failures that are attributed in Inverter ACs are due to this heat dissipation issue. In local service technician parlance, it is called 'Power board' failure. If a thermal melt down happens on the IGBT, sometimes it may melt the PCB copper pad (in which it sits) itself and generally that PCB is not recoverable. If there are component failures, it can be recovered and resoldered except micro controllers which you need to get with the software.

[H_Dogg72]

Warranty is the way to go with inverter AC and expect lifecycle of warranty period only.

[dsr001]

Originally Posted by vijaysrk

What you need a VRV system, but do you really have a use case for it? VRV systems are good for office environments where the duty cycle of operation of the multiple IDUs tend to be high.

For homes, it might just be cheaper (initial cost wise) and easier to go for individual units.
Another issue with VRV systems is that you have a single point of failure in the form of the ODU. With multiple independent units, you have some redundancy as well, if that makes sense.

Thanks.

At my home, we have space for just 1 ODU, due to various reasons. Hence the ask.

Can you suggest some brand/provider as well.

[sagarpadaki]

Originally Posted by Aroy

The hysteresis is due to the temperature sensor. It is either dirty or has moved away from the cooling coil. If it is just hanging in the air, it will sense the air temperature and not exit temperature.

FIX
. Locate the sensor, in most AC's it is clipped on to the evaporator coil (front side for window AC).
. Clean the sensor if dirty and clip it on to the coil.

If this still does not work the either the sensor or the MB needs looking into.

I think I remember seeing something clipped onto the cooling coil fins when I last removed the IDU cover to clean the filters. It might be the temperature sensor. I will try cleaning the sensor with IPA and see if it addresses the problem

[Ottomatic]

Do check if fresh air intake window is opened. It will draw air from outside. May be outside smell entering. It's just a thought as many window air conditioners have this fresh air intake small window.

[vijaysrk]

Originally Posted by dsr001

Thanks.

At my home, we have space for just 1 ODU, due to various reasons. Hence the ask.

Can you suggest some brand/provider as well.

Daikin seems to have a VRV offering for residential applications, others likely do, too.
This is the Daikin VRV products page:
https://www.vrvhome.com/

[satchit_bhp]

I bought a General 1 Ton Inverter AC, they also provide 5 years warranty on PCB and 10 years on the compressor.

Originally Posted by kiranknair

Very good on behalf of Mitsubishi to give 5 years warranty on PCB. PCB on inverter ACs (2 of them I guess) cost a bomb to replace. And PCBs can go kaput, especially in areas prone to voltage fluctuations without stabilizers. The whole reason I went for Panasonic inverter over LG and Daikin where the extended warranty on PCB.