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Old 15th June 2013, 19:00   #3166
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Post Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by R2D2 View Post
If you have supply quality issues (voltage spikes/sags) in your area it would be better to use one.
I do have a Voltage-Stabilizer, but the U4 error may be due to other 'unclean' supply, like frequency (not exactly 50hz) along with voltage spikes/sags, etc.

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Would be good if you can share your experience with their service.
Certainly! Will share my experiences here.

(Have also shared photos/info after my installation in this thread after 20-March-2012).
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Old 15th June 2013, 19:56   #3167
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by R2D2 View Post
....
The range is very wide - 170 to 265V and it does not need a stabiliser though I am using the one the was fitted to my old room AC.
....
I would suggest removing the stabilizer.
These cause more problems than they solve.
If the manufacturer says the voltage range is 170 to 265 volts, you can remove the stabilizer.
Stabilizers give sharp voltage spikes every time the voltage step is changed.
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Old 16th June 2013, 08:58   #3168
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by Aroy View Post
The upside of individual splits is that you control what is on and what is not. If in the 5500 sq. feet you need to cool only 1000 most of the time and that too at different levels, then individual splits are more economical.

In case of vrv/vrf you get a one big package. For 5500 square feet I think it will be in the range of 40+ tons. In general you would apportion the IDU as follows

. 4T units in living room and other large areas where a lot of people will be expected - living room, recreational rooms, gym etc
. 3T units large areas where less people are expected at a time - dining areas, home theater, kitchen
. 2T units in large bedrooms
. 1.5T units in smaller rooms
. 0.75-0.5T in toilets and stairwell

The calculation for tonnage depends on the maximum load, so if you expect that 3000 sq. feet with 50 persons are to be cooled to 20 degrees in peak summer you need around 30T, even though the IDU add up to 40-50 tons.

In my experience both the vendor and the user generally err in installing smaller sizes than needed. For integrated system as in your case use the following to arrive at a nominal sizing
. 1T for every 1200 cu.foot ~ 150 sq.feet
. 1T for every 5 persons
. 1T for every 3KW power consumed by appliances (lights, electronics, refrigerators, etc.)

VRF units are highly efficient in the 120% - 20% of rated capacity, so if you install a 35T unit you can go down as low as 7T at high efficiency and to 3T at lower efficiency. In case you use multiple units, then judicious layout will let you go down to 2T. You can consult the following document for further details.
http://www.daikinindia.com/pdf/VRV-Water%20Cooled.pdf

As the systems of this size are extremely expensive, your best bet is to discuss your requirement with Daikin, after studying the above document thoroughly. You will need to install
. ODU of sufficient size. Whether air cooled or water cooled depends on the space you have and the water supply quality at the site. Water cooled have better efficiency in larger units. You may also opt for multiple 10T units working in tandem.
. Location and sizing of the IDU
. The type of management system
. Piping scheme - number of branches
Hi,
Thanks Aroy for your valuable inputs.
I will be talking to Daikin,Mitsubishi & Hitachi for the same.
We are 6 members in the family & do you suggest we opt for vrv versus splits.I would be needing at least 14 to 16 units to cover the entire house & if I opt for the inverter models the costing would probably be much higher vis a vis the vrv.
Also would you be aware of the Maintainence cost involved on the vrv unit on an annual basis.

Thanks.
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Old 16th June 2013, 10:10   #3169
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by anupmathur View Post
I would suggest removing the stabilizer.
These cause more problems than they solve. If the manufacturer says the voltage range is 170 to 265 volts, you can remove the stabilizer.
Stabilizers give sharp voltage spikes every time the voltage step is changed.
You have a point about the spikes but I am using this stabiliser (a V Guard unit, one of the decent brands) so it doesn't turn into electronic junk. It is only about 1.5 years old and still under warranty.

It has served pretty well so far. If it begins to misbehave then it will be taken off.

@Aroy - Thanks for your inputs on AC sizing. It is really useful information.
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Old 16th June 2013, 10:47   #3170
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by R2D2 View Post
.... I am using this stabiliser (a V Guard unit, one of the decent brands) so it doesn't turn into electronic junk. ....
Could you please post the model number?
All stepped stabilizers will give voltage spikes. I'd like to see how this one avoids them.
And, as we all know, spikes = un-clean supply.
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Old 16th June 2013, 10:54   #3171
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Originally Posted by anupmathur View Post

Could you please post the model number?
All stepped stabilizers will give voltage spikes. I'd like to see how this one avoids them.
And, as we all know, spikes = un-clean supply.
I don't believe I said that this particular stabiliser avoids any voltage spikes when shifting from 1 xfr winding to the other.

The model is VG400. I am curious to know how you will determine this as the manufacturer does not provide more than the most basic of technical information. This is not a servo stabiliser so it must be a stepper IMO.

Last edited by R2D2 : 16th June 2013 at 10:57.
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Old 16th June 2013, 11:13   #3172
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Default Re: Which home/office AC (air conditioner) to buy ?

Till date all my AC run without stabilizers, excepting the Daikin Inverter, where the stabilizer was put by the installer (will tolerate it for one year and thane take it out). The reason I have done away with automatic stabilisers is that all the problems with AC were due to stabilsers, and once they were taken out the AC behaved.

Another thing I noticed is that the stabilizer was consuming 3A over and above that consumed by the AC. At one time I had a 5KVA servo stabilizer which never gave any of these problems.

Unless the voltage stabilizer is a servo motor type, it uses relays to select the correct taps in an auto transformer. An improperly designed circuit would result in voltage spikes every time it changed the tap.

A dangerous situation develops if after consistent low voltage, say 180V the mains returns to 240V (happens when the massive load creating low voltage is taken off the grid). Before the stabiliser can react you would be getting (230/180)*240 = 320V, and that would do much more damage to the electronics than consistent low/high voltage.
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Old 16th June 2013, 11:20   #3173
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by Aroy View Post
Till date all my AC run without stabilizers, excepting the Daikin Inverter, where the stabilizer was put by the installer (will tolerate it for one year and thane take it out). The reason I have done away with automatic stabilisers is that all the problems with AC were due to stabilsers, and once they were taken out the AC behaved.

Another thing I noticed is that the stabilizer was consuming 3A over and above that consumed by the AC. At one time I had a 5KVA servo stabilizer which never gave any of these problems.

Unless the voltage stabilizer is a servo motor type, it uses relays to select the correct taps in an auto transformer. An improperly designed circuit would result in voltage spikes every time it changed the tap.

A dangerous situation develops if after consistent low voltage, say 180V the mains returns to 240V (happens when the massive load creating low voltage is taken off the grid). Before the stabiliser can react you would be getting (230/180)*240 = 320V, and that would do much more damage to the electronics than consistent low/high voltage.
+1 to what you & anupmathur have posted. Thanks for your inputs once again.

Of course the Daikin dealer suggests fitting a stab but that may be due to commercial considerations rather than preserving the longevity of the appliance.

AC installation instructions also mention that a stabiliser is not required because the AC cuts off should there will wild swings in the voltage. The safe voltage for this model (R32 1.8T Inverter split) is 170-265V which is a pretty wide range.

Fortunately we don't have too many power issues in my residential area. I'll be removing the stabiliser shortly.
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Old 16th June 2013, 12:46   #3174
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Default Re: Which home/office AC (air conditioner) to buy ?

Quote:
Originally Posted by R2D2 View Post
...
The model is VG400. I am curious to know how you will determine this as the manufacturer does not provide more than the most basic of technical information. ...
Any product that does not provide more than the most basic specifications is suspect, in my book.

You are right that this stabilizer will also suffer from the problem of spikes in the output voltage since it is relay based.

I discarded all such stabilizers a few years ago and have fitted voltage guards from Sollatek: http://www.flipkart.com/sollatek-a-c...mdk6rysgaujbwh
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Old 16th June 2013, 13:47   #3175
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Default Re: Which home/office AC (air conditioner) to buy ?

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Originally Posted by anupmathur View Post
Any product that does not provide more than the most basic specifications is suspect, in my book.
+1 Fully agree, they obviously don't have much to impress anybody with even a bit of technical knowledge.

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Originally Posted by anupmathur View Post
I discarded all such stabilizers a few years ago and have fitted voltage guards from Sollatek: http://www.flipkart.com/sollatek-a-c...mdk6rysgaujbwh
Thanks for this tip.

Did a bit of reading on Sollatek. I will seriously consider switching over to these products for my electrical appliances.
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Old 16th June 2013, 14:13   #3176
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Default Re: Which home/office AC (air conditioner) to buy ?

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...
Thanks for this tip.
....
You're welcome!

Here's another: If the Maker's manual does not say it in writing that a voltage stabilizer is mandatory for warranty to be honoured it should be clear why 'dealers' are so insistent on one being fitted!
I am surprised that manufacturers of appliances have not specifically stated that warranty would be void if a typical after market voltage stabilizer is used!

The 'protection' built into most of the appliances/gadgets we buy is superior to what the likes of V-Guard are ever going to offer! A visit to their 'manufacturing facility' would be an eye opener!
Bluebird and Logicstat are probably the only stabilizers that are anywhere close to being honest to goodness products. And, anyway, I don't advise using these either!

Samsung, for one, is a company that is clearly writing on their fridges and TVs that a voltage stabilizer is NOT needed. A good start.
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Old 16th June 2013, 16:27   #3177
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Default Re: Which home/office AC (air conditioner) to buy ?

@anupmathur - I used to repair consumer electronics as a hobby in my younger days. Once one of the current V Guard stabilisers is 'retired' I'll take it apart to check the quality of components including the PCB, XFR etc.

It would be interesting to see what these guys use. These units are pretty light weight and I am not expecting anything but El-Cheapo components.
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Old 19th June 2013, 19:25   #3178
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Post Daikin Complaint

Daikin complaint was attended today (Model:FTKD60FVM 1.8T Inverter 15 months old).

Complaint was:
1) Intermittent 'whoosh' fan-noise in IDU
2) Low Cooling
3) Horizontal-Vanes not working

I had raised a service-call on Daikin's web-site and also contacted the installer.
Response was prompt, I received a call from the installer and an email & SMS from Daikin.
This time they sent a senior guy along with the original installer.

This senior took apart the IDU fan, etc quickly (He was trained well).
Then they cleaned the bits and pieces with shampoo thoroughly.
The ODU was cleaned with (low pressure) water jet.
Overall they did a very good job of cleaning.
He insisted that the noise was due to dirt and will vanish after cleaning.

Unfortunately after assembling the noise may have increased!
They then called someone senior in Daikin (maybe in Chennai/Bangalore).
One question I overheard was: were the lines vacuumed during installation. I immediately butted in: No!

I had reported on this thread (March-2012) that vacuuming was not done to remove the moisture in the lines during installation.

Now this could be the problem, the idiot-installer insisted it was not necessary when he did the install.

Now this senior person suggested: Let us open the lines and again refill with gas (R22) after vacuuming along with thorough water wash of the IDU components. The cost may be upto Rs.2,000.

But what if the problem is not solved even after I spend this?
And I am out of warranty (compressor itself is covered for 5 years).
Anyway the installer was at fault, so they should bear the cost after admitting their mistake?

I am yet to decide and have asked for one to two days to decide.

I want to maintain friendly terms with the service guys, after all I have already invested Rs.53,000+ and need them to maintain this for at-least 4 more years.

One good gesture I got was: I was not charged Rs.500 for this cleaning-service yet, I was told that I can pay after they solve the problem.

Still have faith in Daikin!
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Old 19th June 2013, 20:32   #3179
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Default Re: Daikin Complaint

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I had reported on this thread (March-2012) that vacuuming was not done to remove the moisture in the lines during installation. Now this could be the problem, the idiot-installer insisted it was not necessary when he did the install. Still have faith in Daikin!
Thanks for the update. I had the same experience - the installer did not vacuum the system despite the installation instructions clearly mentioning that it is required.

I guess it means having to lug around extra equipment (the tools, vac pump, etc) and in a country with a "Chalta Hai' attitude to most things, the installer gave what could be an essential step, a skip.

Now I am only a bit conversant about air-conditioning and refrigeration equipment and their innards, but the new ODU runs very silently, there's a slight sloshinhg sound much like sound of water running thru pipes (ODU side). The manual says this sound is normal. Hopefully its not the sound of moisture in the system. Can someone please confirm?

Your feedback has me concerned. To preserve its mechanical longevity I may call Daikin to send a technician to vacuum the system even if I have to pay extra for a gas top up. This unit cost me over 60K including installation charges and I'm not about to risk the new <2 week old AC because of some installer's apparently incorrect advice.

PS - my experience with Daikin's service staff is positive. They came over and did a wet cleaning service of the older Daikin machine about a month back. It was a good job which I really appreciated. In stark contrast with my experience with Carrier.

Last edited by R2D2 : 19th June 2013 at 20:38.
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Old 20th June 2013, 14:17   #3180
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Default Re: Which home/office AC (air conditioner) to buy ?

Hi guys,

I am looking for a 1.5 Ton AC for a 200 sq feet home theater room. As it is not going to be used every day, I am not looking at a very high-end model. Anything appropriate? Budget is as less as possible :-) Should not be too noisy.
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