[Aroy]

Originally Posted by devarshi84

The Hitachi Star 2.2 tonne with scroll compressor I got installed is an awesome unit. Cools the Hall in less than 5 mins.

But it make quite some noise along with the external unit. Is it ok to expect noise from a 2.2? None of the other units make noise but are around 1 tonne in range.

PS: I am talking about the collective noise of both the indoor and outdoor units but excluding the sound of airflow.

Neither should be making a lot of noise.

Call the installer and check if they have removed the "transport restraints", or the fans are striking some where. After my Hitachi window AC lost some gas, I replaced it with Summer Cool series last week. The installer forgot to remove the transport restraint (a block of wood) and it made a lot of noise on starting. When he removed it the AC became super quiet.

As the indoor unit has only a fan, it should be whisper quiet, else the fan or a bit of plastic is vibrating and making the noise.

The Outdoor unit should be quieter than window AC (as heard from outside).

[Thad E Ginathom]

Our local engineer is very good; the only problem is getting him here without a piece of rope!

So it's self-help time.

I took the cover off our Samsung 1-ton (bedroom; the most important AC we have) and cleared the dust off the fan with a paintbrush.

Having done this, it made a high-pitched noise like one of those insects. I located a small label on the fan that had become almost detached and removed it. By the way, I also noticed some small pieces of metal: I suppose these fans must be balanced like car wheels?

Having done this, after a few days the remote failed to work. The sensor/switch/led board was very dirty and probably not positioned correctly. Cleaned and repositioned.

All is now working, giving good draught, and quiet.

Of course, as a beginner, one fixes one problem, unknowingly causing another, but one learns. I have no wish, however, to take the disassembly experience any further, as this would involve disturbing the cooling coil.

[devarshi84]

Originally Posted by Aroy

Neither should be making a lot of noise.

Call the installer and check if they have removed the "transport restraints", or the fans are striking some where. After my Hitachi window AC lost some gas, I replaced it with Summer Cool series last week. The installer forgot to remove the transport restraint (a block of wood) and it made a lot of noise on starting. When he removed it the AC became super quiet.

As the indoor unit has only a fan, it should be whisper quiet, else the fan or a bit of plastic is vibrating and making the noise.

The Outdoor unit should be quieter than window AC (as heard from outside).

The indoor unit is definitely quieter than a window unit. The external unit has been installed after a 5 feet passage near the kitchen. And the outer unit makes enough noise for the person working in the kitchen to be irritated by it.

The installer says it is fine. Should I shoot an e-mail to Hitachi?

[Thad E Ginathom]

Originally Posted by Thad E Ginathom

All is now working, giving good draught, and quiet.

FAIL.

The insect noise has come back. It is intermittent, and sometimes stops with a thump. Could it be a fan bearing?

[Aroy]

Originally Posted by devarshi84

The indoor unit is definitely quieter than a window unit. The external unit has been installed after a 5 feet passage near the kitchen. And the outer unit makes enough noise for the person working in the kitchen to be irritated by it.

The installer says it is fine. Should I shoot an e-mail to Hitachi?

1. The indoor unit should be quieter than in indoor part of the window AC. In fact there should be only the noise of air flow and nothing else.

2. The outdoor unit should be as much or less than the window Ac from outside. If it is making an irritating noise then the fan may be touching the frame.

If possible check a few split unit outdoor units around your house in the locality. If your unit is making more noise than others, then there is some thing wrong.

Any way please call the Hitachi Helpline, as well as shoot an e-mail to them ASAP.

[Guite]

I have a problem with my Daikin split AC bought about 2.5 years back. I am not sure if this problem is particular to me or not. I would appreciate if other Daikin users as well as knowlegable members can share their insight, please.

In the indoor unit there is a long cylindrical thing with metal strips which seems to circulate air by centrifugal action. Previous years, after prolonged usage of say two months the indoor unit would make whoosing sound. Its not a continous sound, its rather like natural wind - whoos... quite... whoos whoos.. The intensity of this noise is proportionate to fan speed. Till last year Daikin technicians would come, clean the unit and then its quite as normal. BTW you would be surprised at how much dirt sticks to those metal strips. Must be air pollution and dusty environment.

However this year its different. Responding to noise complaint the company technicians came and cleaned today but the noise has not vanished. Infact its worse. Later they volunteered that problem is due to PCB. I did not take them up on that. Will pursue further with Daikin.

So I am soliciting fellow members opinion here.

[Torqy]

Originally Posted by Torqy

I'm on the lookout for a 1.5T Split A/C for my office space. 22ft X 19ft. Its not on top floor. There are no windows. Its a sound proofed room.
I know the tonnage might not be enough. But i'm planning to run it for sometime and see if its enough. This thread tells me Daikin is the best.....but a bit over the budget.

Any Voltas / Blue Star users here? What's your opinion on these brands?

-- Torqy

I'd appreciate if any Voltas / Blue Star users here could post their comments. Thanks.

-- Torqy

[Thad E Ginathom]

In the indoor unit there is a long cylindrical thing with metal strips which seems to circulate air by centrifugal action.

Guite, for want of a better word (there's probably a technical one) lets call that long cylindrical thing a "fan," even though it looks nothing like the thing with blades which that word brings to mind. I guess there's just more than one kind of fan.

(err... impeller? I don't know)

The build up of dirt on those blades leads to serious loss of efficiency. On one of my ACs, a few months ago, it was shifting so little air that the cooling coil/fins started to ice up.

That lack of draught is where I started fiddling with my bedroom AC, and now I have this insect noise like holding a small, stiff paper against the fan. Not a whoosh, though.

[khoj]

Originally Posted by Thad E Ginathom

Guite, for want of a better word (there's probably a technical one) lets call that long cylindrical thing a "fan," even though it looks nothing like the thing with blades which that word brings to mind. I guess there's just more than one kind of fan.

(err... impeller? I don't know)

Yes TEG you are correct that is indeed a cross flow fan and there are quite a few different type of fans.

Originally Posted by Thad E Ginathom

The build up of dirt on those blades leads to serious loss of efficiency. On one of my ACs, a few months ago, it was shifting so little air that the cooling coil/fins started to ice up.

That lack of draught is where I started fiddling with my bedroom AC, and now I have this insect noise like holding a small, stiff paper against the fan. Not a whoosh, though.

The insect like noise say a humming or a droning could be due to a cut bushing in the fan. If it is more like a fast click then it could be two things touching when one should be.

@guite,

The whoosh sound usually comes at the start of a cooling cycle when a fresh lot of compressed gas expands in the coil, it can be quite noisy the level varying from machine to machine. It settles down once the initial burst of gas has gone through. A whoosh set in by the fan would have to be air cutting noise but then that would be continuous at a given speed. It would be interesting to find out as to what does the pcb has to do with this. Were these guys actual technicians or apprentices who were sent in to be fillers.

@Torqy

Get a Whirlpool.

[HotChillyPepper]

Originally Posted by devarshi84

The Hitachi Star 2.2 tonne with scroll compressor I got installed is an awesome unit. Cools the Hall in less than 5 mins.

But it make quite some noise alongwith the external unit. Is it ok to expect noise from a 2.2? None of the other units make noise but are around 1 tonne in range.

PS: I am talking about the collective noise of both the indoor and outdoor units but excluding the sound of airflow.

My brother had installed the same unit but didn't notice any noise issues. The unit is very powerful and cools the whole hall in less than 5 mins.

[devarshi84]

Yes, the unit is much more powerful than most 2star ac's in the market and expensive too. I could've decided on a smaller unit. :P It chills(not cooling but chilling) in 5-10mins which is the fastest I have seen to date.

I have not been able to do much since I am away from home for sometime. But I did complain to the company and they are sending a team to check it out tomorrow.

PS: Comparing Voltas, Daikin, Videocon and Hitachi, I would say Hitachi's company response has been the fastest. Will post what happens.

[Guite]

Originally Posted by khoj

@guite,
The whoosh sound usually comes at the start of a cooling cycle when a fresh lot of compressed gas expands in the coil, it can be quite noisy the level varying from machine to machine. It settles down once the initial burst of gas has gone through. A whoosh set in by the fan would have to be air cutting noise but then that would be continuous at a given speed. It would be interesting to find out as to what does the pcb has to do with this. Were these guys actual technicians or apprentices who were sent in to be fillers.

I wasn't at home when the service took place. So I am not able to judge their capability. They responded to a noise complaint. They cleaned the unit. The noise has not subsided. Then they blame the pcb. That does not sound like engineers to me. I am not even sure whether they checked the pcb or did any diagnostics. Anyway I am glad you concur that pcb fault is unlikely cause.

[Aroy]

Originally Posted by Guite

I wasn't at home when the service took place. So I am not able to judge their capability. They responded to a noise complaint. They cleaned the unit. The noise has not subsided. Then they blame the pcb. That does not sound like engineers to me. I am not even sure whether they checked the pcb or did any diagnostics. Anyway I am glad you concur that pcb fault is unlikely cause.

For the fan to be silent, there has to be near zero turbulence in the air throw, notice the difference between the tent house pedestal fans and a well designed cooler fan. For similar air throw the former makes much more noise than the latter.

Your sound may be due to fan working improperly. For getting a large air flow with very little noise (lower turbulence!), the fan has to be designed properly and rotational velocity controlled to give optimum air flow without excessive turbulence (which is where the noise is generated).

I am speculating
- the fan may have a DC/servo motor which is controlled by the PCB in question, regulating rotational velocity, like a helicopter rotor to get the maximum air flow with minimum turbulence. If the PCB is faulty the fan would be rotating at a constant velocity to produce the "whoosh" noise, as in a normal AC. As you have noted that when there is dirt accumulating on the fan it is no longer silent - the controller has not taken the increase in mass of the rotor into account! If my diagnosis is correct, then the dirtier the fan blades get, the louder the noise.

[Aroy]

For those who are searching for portable cooling solutions

Suiden Products | Industrial Portablel Portable Air Conditioners Spot Coolers for industry

These seem to be AC and not water coolers.

[Thad E Ginathom]

the dirtier the fan blades get, the louder the noise.

That is my experience.

Add also, "the less air gets shifted"