Inverter Air Con.

[AsiaCheese]

Sounds to me as if the control electronics are out to lunch. There's no good reason why the compressor should turn itself off unless the target temperature is reached (and held for a while). The "techies" in Thailand - even the ones from manufacturers - tend to have a pretty dubious technical background (professionally qualified? not really...) and pull the first available rabbit out of the hat - you need more BTUs.

When I bought a new inverter aircon a few months ago, I did my own BTU research on the web. It looked to me as if in Australia, you fairly often see 300 BTU/sq.m. as a reference, while some go up to 600 BTU/sq.m. There isn't a single number for every situation - too many factors influence it, like good/bad insulation, window vs. wall area, top floor (additional heat thru roof), outside walls, sun exposure vs. having neighbors on 3 sides etc. etc. The biggest factor [in Thailand] is the shop wanting to sell you a very large unit: it's the same margin on cheaper and pricier units...

I have one outside facing wall (all glass, lousy insulation), a badly insulating entrance door and the top floor bonus-malus, with around 35 sq.m. actual room area. Before, I had a 12k BTU (!!!) unit for 7 years, until the copper tubes in the compressor developed small holes where the gas evaporated (living on a beach can make things go boom). I use the aircon mostly at night, at 26-28°C setting. That worked fine, even with the "underpowered" old solution while it was still alive. When I replaced it with a Panasonic Inverter setup, the [farang] installer said 24k at least. I objected and said that I have no desire to go to 18°C... I ended up with an 18k BTU unit, which does a great job, has cut my electricity bill considerably so far, keeps a pleasant humidity level in the room (which is more important than the actual temperature), the compressor stays mostly at fairly low revs and occasionally turns itself off altogether (not so much now in the very-hot season, but when outside temps are between 30-35°C). According to the sq.m. x 600 calculation, I should have 21k BTU.

I've heard many times that too many BTU will cool the room too quickly, not leaving enough time to dehydrate the air, which from a physics point makes good sense. IMHO, the only "risk" of being slightly on the low side is that the compressor will spin more often and at higher revs, costing you a bit more electricity. The short version of a long rant: if your compressor turns off while it should be running, there's a fault in the electronic control system.

[alfredmarks50]

Hi, there are several settings under mode( on the remote) your unit could be set to dry instead of cool

try setting 21 C , cool and keep the airco running, if the compressor stops you have a problem in the system, the cooling tubes might be partly blocked.

The guys who installed my airco could not find this same problem and a qualified engineer from the factory came and changed a coil. Works fine now.

I use a 18K for 45sqm room. good luck

[CGW]

If your 18k unit is undersized for the room, it will run the external unit constantly in a vain attempt to attain your temperature setting. I don't think it's undersized, but beware of windows, walls and roofs exposed to the sun (solar gain). Double glazed windows are not protection from sunlight. Same, but to a lesser extent, for walls and roofs.

I do think that your selected room temp is a little unrealistic. With an outside temp in the high 30s, the most you should try to achieve is a reduction of 10c. For example say around 26 or 27c. But that is a "by the way" and of no importance to your current problem.

Your experts probably have little or no experience, other than a new installation so try this .... Firstly, put new good quality batteries in the remote control. Weak batteries will send the wrong signal to the wall unit. Secondly, check the electrical cable used and the quality of the connections made. An aircon should have a single unjoined cable direct to the distribution board and with its own breaker. Thirdly, now you need to check the gas in the system for pressure / content. The best plan for that is to drain and replace, making sure that the gas is exactly as detailed by the manufacturer. Before you do that a rough sort of test for the gas is to feel the pipes just as they enter the outside unit. One should be very cold to the touch, the other should be around the ambient temperature. If both of the pipes feel cold it may suggest that too much gas or pressure or the wrong gas has been mixed with the shipped unit. If the new batteries and cabling seem ok, I feel sure that both of your pipes will feel cold.

Very helpful reply, I too would expect the unit to constantly run to try and attain my (unrealistic!) temp expectation.

I also have my doubts about the "experts" there is a lot more to Inverter AC than the normal type they are familiar with, are they given training? probably not.

I will go through your checklist and seee what I can come up with.

Thanks

Your manual that came with your airconditioner will in the specifications setting have an operaing range. I will give a maximum number of degrees below ambient it can cool. Check you have not exceeded that.

Just checked manual rating is for 8c differential, which during the day with the temp in the high thirties would not be attainable, but the AC is only run at night when the temp is below 30c so 23c should be possible.

Thanks

[Brian Robson]

Scotty's engineering Law

A good engineer always keeps 20% in reserve!

Applies to AC capacities too

[CGW]

Sounds to me as if the control electronics are out to lunch. There's no good reason why the compressor should turn itself off unless the target temperature is reached (and held for a while). The "techies" in Thailand - even the ones from manufacturers - tend to have a pretty dubious technical background (professionally qualified? not really...) and pull the first available rabbit out of the hat - you need more BTUs.

Agreed! thats why I am dubious of their findings!

[Anthony5]

Measure the temperature the indoor unit blows. At full power setting it should blow about 7° air after running for about 30 minutes.

[ToddinChonburi]

Do not run on AUTO make sure you use the 1 or 2 fan setting. I have a 15000 BTU and I run on low setting and has no problem cooling 40 sqm

My old place had a Mitsi 18,000 and it turned the place into an ice box with the patio facing west.

[Pib]

Measure the temperature the indoor unit blows. At full power setting it should blow about 7° air after running for about 30 minutes.

That might be pretty aggressive for many A/Cs if it's around 30C or higher outside during the day, but I'm sure some can do it. At night that 7C may be reachable for a higher percentage. And I based that on personal measurements over the years by measuring the temperature just inside the A/C vent outlet 50-55F for an A/C when it hot outside during the day...means it's operating fine...better than that and it doing excellent. And just to note, although the air might be very cold at that measurement point, if the roller fan and/or filters are dirty there significantly less air being blown into the room which would make a person think it's not cooling very well.

http://inspectapedia.com/aircond/Air_Conditioner_Temperatures.php

Temperature leaving the air handler's evaporator coil: similar to above, measure the supply air temperature at a hole or crack in the supply plenum above (or "downstream from) the evaporator coil. It should be around 55 degF. Some experts argue that this is the only accurate way to examine the cooling system and that measuring temperatures across the evaporator coil is unreliable.

[shaurene]

In New Zealand we work on 1kw per 7-8 sqr mt but the hot temps here you should work on 5 Sqr mt per kW.

You have room 35 sqr mt so you need 6kw unit. 18,000 btu is 5.2 kW so you are a little bit to small Mate and it does make a difference.

[purple123]

A standard room usually consume around 100 to 125 watts per sqm. However, to test the unit put it on high fan, cooling mode and drop the unit to 18 and test the evaporator incoming and outgoing air. It should have around a 11 degree differential.

G

[purple123]

Furthermore, you say the unit is an inverter- can y confirm what is cycling off. The condenser fan motor or the compressor?

G

[jacko45k]

My Daikin has a 'magic eye' which says something about raising the set temperature if no movement is detected in the room for a set time.

Of course I turn it off and run it in straight cool mode,

If you have set the unit definitely to cool, with no energy saving features enabled, set to say 22-24 deg C, and the compressor is shutting down while the room is still warm, check there is no icing up, and air is flowing well over the thermometer, normally located where the air is taken back into the wall unit. Ensure filters are clean too. It may seem silly but ensure chilled air isn't being taken directly back by the unit... ie direct it down and away. Other than that I suspect a faulty control unit.

[Pomthai]

Inverter units contrary to popular belief and what many local tech will admit too, are a very different beast to the old traditional cycle on, cycle off units.

From my experience and coupled with the OPs description. I would guess that the unit is overcharged with refrigerant. From a fresh start, I'm guessing

the compressor runs, labors and cuts out due to overheating or high pressure cut out switch.

Ideally to correctly charge an Inverter unit if its not factory charged, is the weigh the refrigerant into the system. It will say on the outside unit (CDU) how many grams and this will be based upon the standard piping length supplied. More refrigerant will need to be added if the pipe work is significantly longer than normal and the installation guide will have a calculation for this.

You can determine if it is overcharged by measuring the current draw and comparing that to what the details on the CDU say. If its over the rated amperage, then its overcharged assuming there are no other failed components like stuck fans etc.

[carlyai]

As I said I realise 18k is minimal for a room this size, but given AC is not run in the day and insulation and windows are about as good as you can get in Thailand I though/hoped it would be ok, as Pib states salesmen will always oversell BTU which leads to extra running costs/less efficiency.

Mitsubishi have sent 2 experts to look at "problem" they both state AC too small for room, after performing some lenghy tests, - I can accept that! but why isn't the compressor running all the time? rather than ramping down to a sleep mode, if the compressor was screaming all the time AC was running I would happily accept that it was too small. This AC was one of five (MSY-GK???) that were fitted at the same time, the others have been no problem.

MichaelJohn, I have reread manual and can only see what I posted re: 2 deg in cool modeno other option?

Cheers

I have Daikin inverter aircons and they also stop completely at one point.

Inverter aircons will have variable speeds, thereby regulating the current they use, but at one point they do completely stop .

Edit to add:

An inverter aircon slows down when it almost reaches the set temperature, but stops completely when it reaches the set temperature, then starts again slowly when the temperature rises above thea set temperature.

http://www.refrigeration-engineer.com/forums/showthread.php?40129-Panasonic-Inverter-Compressor-Stops

Sorry I can't help on this, but, I'd like to ask the guy with the Daikin inverTER questions.

Did the guy who put your Daikin inverTER air cons in put in an earth rod with every invertER?

I had 3 put in recently and the install guy insisted, really insisted, he put in 3 earth rods, as he said inverters need earth rods, but he never puts them in normal aircons.

He said because they are inverTER they have to have earth rods, or they will get damaged.

I think his Daikin trainers have told him this.

The very learned people, who I believe, on this forum say 'not true'..

And Aussie land says only one earth rod per house.

So you got earth rods per Daikin or not?

[Pib]

Does you residence have 3-wire wiring? That is, includes the safety ground wire.

Many Thai residences/building only have 2-wire wiring--no safety ground...so, maybe the Daikin guy is just adding the earth ground when the residence is only a 2-wire residence.

[chang1]

I am a refrigeration engineer so hopefully I can help you out. Although Without checking the A/C myself a true diagnosis is nearly impossible which is why you are getting so many different suggestions.

The relevant facts I am looking at or assuming are

1 - Brand new air con

2 - Installed to normal poor Thai standards with minimal equipment

3 - Undersized

4 - Compressor stopping and restarting before reaching set temp.

5 - Room insulated and well sealed

6 - power supply is suitable

7 - No fault codes shown

8 - other A/Cs all work fine

9 - good airflow around indoor and outdoor units

10 - Unskilled "experts" sent by manufacturer

In short I think it is short of gas.

This will cause part of the evaporator to get too cold and start to ice up. The evaporator sensor will then tell the compressor to slow down or even stop. Take a look at table 3 on page 5 of the pdf harry linked to in post #30.

This can easily be checked as billphillips suggested in post #27 by feeling the pipes on the outside unit but I disagree with him about what you should feel. There are 2 insulated copper pipes which go to valves on the outside of the unit probably behind a cover. The smaller pipe is the going to the evaporator and the larger is the suction pipe coming from the evaporator. Old A/Cs have the restrictor in the evaporator so the small pipe would be warm or just above ambient and the suction would be cold and sweating (have condensation were not insulated). However modern A/Cs have the restrictor in the outside unit so BOTH pipes should be cold and sweating.

If you see that the small pipe is a lot colder or even has ice on it and the other is not sweating it is most likely short of gas.

I had air con fitted at our house in Thailand this year and saw how poor the installer was - hardly surprising as it was fitted for free. As he did not have a vacuum pump (or almost any tools) he used some of the gas to clear the air out of the evaporator and pipes. I then insisted he went and borrowed a vac pump and did it properly. This he did but half hearted and as he did not have any gas to top up the system I also now have a system short of gas but not too bad.

As billphillips says I also recommend taking out the gas, vacuuming the complete system and recharging it with the correct weight of fresh gas. Make sure it is the correct gas - probably R410a as the wrong gas can also give this problem (and others). The gas type and weight will be on the outside units label. Good luck in finding someone with the correct gear and skills to use it. More likely they will just top up the gas which is near impossible to get right with an inverter A/C but they should still get it working.

[Pib]

One more recommendation for the OP since he had several of the Mitsubishi's installed which probably have identical/very similar remote controls and since some of his problem description implied to me the A/C seemed to reach desired temp in some cases. Since the remote is what a person uses to set the A/C to whatever mode (i.e, I Feel Good Mode, Sleep Mode, Timer Mode, Cool Mode, etc) maybe the wrong settings are being used or the remote is bad.

Maybe take a remote from one of the other Mitsubishi A/Cs that is cooling properly, use that remote control to turn off the problem child A/C for a few seconds and the use that remote to turn it back on again. When turned on the mode settings in that remote will be transmitted to the A/C setting it to the mode which was allowing the other A/C to work/cool properly....maybe the problem child A/C will start working properly also.

[MartinL]

Not directly relevant to the OP but, I hope, useful background information.

I wouldn't build a well-insulated house in Thailand and this is why:-

In a "normal" Thai concrete/brick house of pillars & single-layer brick/block walls, the walls are very thin & quite lightweight - they have a low thermal capacity. As a result, they heat-up quickly when the sun is on them and the heat is transferred to the room quite quickly, heating-up the room. As a consequence of this construction, when the sun goes down, the walls lose heat quickly and heat begins to be transferred from the room to outdoors. If your room is at 35C (as my bedroom frequently is when the sun goes down) and outdoors is less than that, the room loses heat to the exterior. Besides the air temperature in the room, there's also the radiant heat emitted from a hot building structure which adds to the uncomfortable sensation of heat. While any normal thermometer will tell you the air temperature, it can't tell you the effect of radiant heat emission from walls, which can be significant. In building services engineering, we use a combination of air & radiant temperatures as our working temperature rather than just air temperature.

Part of the problem with a well-insulated building is that it doesn't PREVENT heat getting into a room, as is commonly thought, it just delays the process - a property known as thermal lag. It also prevents a room losing heat to the outdoor environment as quickly as a lighter, less well-insulated structure. Because the well-insulated building structure transmits heat to the room more slowly, the peak temperature in the room might occur at, say, 9pm rather that 6pm, just when you might be thinking about turning-in.

To achieve a good room temperature, your a/c must not only cool the air but also attempt to cool the building structure too. In a lightweight building much of the cooling of the structure occurs naturally by rapid transfer of heat from structure --> outdoors, leaving less work for the a/c to do. The well-insulated building & its later peak temperature will mean your a/c must work harder or be switched on much earlier.

Orientation of a room is important - have your bedrooms on the east or north side of a building if possible, so that the impact of the sun on the building is reduced. A north-facing room gets little soar radiation while an east-facing room receives sunlight in the early part of the day and has the remainder of the day to cool down. Although you might think otherwise, a south-facing room is better than west-facing because the sun is almost directly overhead and the roof space act as a buffer between outdoors & the room and absorbs a lot of the heat gain due to solar radiation.

Hope this makes some sense - it's an attempt at a very simple explanation of complex building thermal dynamics.

[luk AJ]

Can you check where the temperature probe is located? If it is close to the cooling pipe or close to air outlet the airco will "think" set temperature is reached and will shut down.

[Anthony5]

Measure the temperature the indoor unit blows. At full power setting it should blow about 7° air after running for about 30 minutes.

That might be pretty aggressive for many A/Cs if it's around 30C or higher outside during the day, but I'm sure some can do it. At night that 7C may be reachable for a higher percentage. And I based that on personal measurements over the years by measuring the temperature just inside the A/C vent outlet 50-55F for an A/C when it hot outside during the day...means it's operating fine...better than that and it doing excellent. And just to note, although the air might be very cold at that measurement point, if the roller fan and/or filters are dirty there significantly less air being blown into the room which would make a person think it's not cooling very well.

http://inspectapedia.com/aircond/Air_Conditioner_Temperatures.php

Temperature leaving the air handler's evaporator coil: similar to above, measure the supply air temperature at a hole or crack in the supply plenum above (or "downstream from) the evaporator coil. It should be around 55 degF. Some experts argue that this is the only accurate way to examine the cooling system and that measuring temperatures across the evaporator coil is unreliable.

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

[Anthony5]

As I said I realise 18k is minimal for a room this size, but given AC is not run in the day and insulation and windows are about as good as you can get in Thailand I though/hoped it would be ok, as Pib states salesmen will always oversell BTU which leads to extra running costs/less efficiency.

Mitsubishi have sent 2 experts to look at "problem" they both state AC too small for room, after performing some lenghy tests, - I can accept that! but why isn't the compressor running all the time? rather than ramping down to a sleep mode, if the compressor was screaming all the time AC was running I would happily accept that it was too small. This AC was one of five (MSY-GK???) that were fitted at the same time, the others have been no problem.

MichaelJohn, I have reread manual and can only see what I posted re: 2 deg in cool modeno other option?

Cheers

I have Daikin inverter aircons and they also stop completely at one point.

Inverter aircons will have variable speeds, thereby regulating the current they use, but at one point they do completely stop .

Edit to add:

An inverter aircon slows down when it almost reaches the set temperature, but stops completely when it reaches the set temperature, then starts again slowly when the temperature rises above thea set temperature.

http://www.refrigeration-engineer.com/forums/showthread.php?40129-Panasonic-Inverter-Compressor-Stops

Sorry I can't help on this, but, I'd like to ask the guy with the Daikin inverTER questions.

Did the guy who put your Daikin inverTER air cons in put in an earth rod with every invertER?

I had 3 put in recently and the install guy insisted, really insisted, he put in 3 earth rods, as he said inverters need earth rods, but he never puts them in normal aircons.

He said because they are inverTER they have to have earth rods, or they will get damaged.

I think his Daikin trainers have told him this.

The very learned people, who I believe, on this forum say 'not true'..

And Aussie land says only one earth rod per house.

So you got earth rods per Daikin or not?

No my aircons don't have an earth rod, but every aircon has his dedicated breaker which are behind an RCBO ( safety cut ) and of course the breaker box is properly earthed.

I have had the whole Daikin technical team here, from the local Daikin technician to the general technical manager and the Japanese CEO, to solve an issue and never was something mentioned about an earth rod.

[Naam]

Measure the temperature the indoor unit blows. At full power setting it should blow about 7° air after running for about 30 minutes.

That might be pretty aggressive for many A/Cs if it's around 30C or higher outside during the day, but I'm sure some can do it. At night that 7C may be reachable for a higher percentage. And I based that on personal measurements over the years by measuring the temperature just inside the A/C vent outlet 50-55F for an A/C when it hot outside during the day...means it's operating fine...better than that and it doing excellent. And just to note, although the air might be very cold at that measurement point, if the roller fan and/or filters are dirty there significantly less air being blown into the room which would make a person think it's not cooling very well.

http://inspectapedia.com/aircond/Air_Conditioner_Temperatures.php

Temperature leaving the air handler's evaporator coil: similar to above, measure the supply air temperature at a hole or crack in the supply plenum above (or "downstream from) the evaporator coil. It should be around 55 degF. Some experts argue that this is the only accurate way to examine the cooling system and that measuring temperatures across the evaporator coil is unreliable.

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

this temperature depends on the prevailing room temperature and can vary a lot. no 12k unit has an outlet airflow of 7ºC when switched on in a room which warmed up to 28 or 30ºC.

[Anthony5]

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

this temperature depends on the prevailing room temperature and can vary a lot. no 12k unit has an outlet airflow of 7ºC when switched on in a room which warmed up to 28 or 30ºC.

Will you agree and offer apologies if I take the test and post a picture of the thermometer?

If I don't get the 7°C or thereabout I will offer the same.

[thailandforumaddict]

I am also disappointed by daikin inverter, is this system too new and makes problems ?

[billphillips]

I just thought of something and it may have some value or not. It will cost you nothing other than a few minutes of your time so it's possibly worth a try.

Turn off the aircon at the main switch and remove the batteries from the remote at the same time. Wait a few minutes and switch back on and replace the batteries. Both items should do a "re-boot" from the embedded memory. It's worth a try!

I thought that the posters suggestion of using an alternate remote was a good idea, the wall unit will only do what the remote tells it to. Wrong message = wrong action.

[RBOP]

I'm using an 18K Inverter (Toshiba) in my 35sq.m bedroom and cools it just fine. But note, Inverters take much longer to cool a room compared to non-inverters. When I turn on the aircon if room temperature is say 30C it will take about 2 or 3 hours to get it down to 22C.

By the way, my Toshiba is about 5 years old and rattles and hums quite annoyingly. How old is your Mitsu and how's the noise level? I'm thinking of getting the Mitsu SuperInverter 18K.

[Pib]

Measure the temperature the indoor unit blows. At full power setting it should blow about 7° air after running for about 30 minutes.

That might be pretty aggressive for many A/Cs if it's around 30C or higher outside during the day, but I'm sure some can do it. At night that 7C may be reachable for a higher percentage. And I based that on personal measurements over the years by measuring the temperature just inside the A/C vent outlet 50-55F for an A/C when it hot outside during the day...means it's operating fine...better than that and it doing excellent. And just to note, although the air might be very cold at that measurement point, if the roller fan and/or filters are dirty there significantly less air being blown into the room which would make a person think it's not cooling very well.

http://inspectapedia.com/aircond/Air_Conditioner_Temperatures.php

Temperature leaving the air handler's evaporator coil: similar to above, measure the supply air temperature at a hole or crack in the supply plenum above (or "downstream from) the evaporator coil. It should be around 55 degF. Some experts argue that this is the only accurate way to examine the cooling system and that measuring temperatures across the evaporator coil is unreliable.

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

Not saying your particular A/C can't achieve 7C...like I said I'm sure some A/Cs can achieve that, but I don't think that is the standard everyone should expect to achieve with their A/C. Many A/Cs will not achieve that even when brand new. I did a temperature measurement on all of my 7 York A/Cs within a few weeks of them being installed so I could get a reference temp so I would have something to go off of in the future. Done a few vent measurements of neighbor A/Cs when they thought they were having home cooling problems. In Hawaii, I drill a small hole in my central air plenum chamber right after the air exits the cooling fins to get my reference measurement. Did a similar thing at another Hawaii home with central A/C. 50-55F/10-13C is what I always got...a few times down to almost 45F/7C on a cool day/night when you didn't really need A/C. Even auto A/Cs put out approx the same 50-55F temp when siding a wire temp probe a couple inches into the vent on a hot day....down around 45F/7C on a cool day/at night. The goal is to basically do the temp measurement as close as possible to the evaporator air output to minimize errors. All of these personal measurements over the years match up with references on the web. You'll also see general rule of thumb of expect to see 35-40F temp differential between the outdoor temp and home/car A/C vent output temp. But don't expect to see your car A/C blowing below freezing vent air if using it during the winter in Alaska because the design of the A/C shouldn't allow that.

Edited May 24, 2015 by Pib

[chang1]

Measure the temperature the indoor unit blows. At full power setting it should blow about 7° air after running for about 30 minutes.

That might be pretty aggressive for many A/Cs if it's around 30C or higher outside during the day, but I'm sure some can do it. At night that 7C may be reachable for a higher percentage. And I based that on personal measurements over the years by measuring the temperature just inside the A/C vent outlet 50-55F for an A/C when it hot outside during the day...means it's operating fine...better than that and it doing excellent. And just to note, although the air might be very cold at that measurement point, if the roller fan and/or filters are dirty there significantly less air being blown into the room which would make a person think it's not cooling very well.

http://inspectapedia.com/aircond/Air_Conditioner_Temperatures.php

Temperature leaving the air handler's evaporator coil: similar to above, measure the supply air temperature at a hole or crack in the supply plenum above (or "downstream from) the evaporator coil. It should be around 55 degF. Some experts argue that this is the only accurate way to examine the cooling system and that measuring temperatures across the evaporator coil is unreliable.

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

I may not be an expert but I have no idea why anyone, yet alone an expert, would say that a 55 deg F air off temp is the only accurate way to examine an A/C. There are many variables that would change the air off temp. so by itself it tells you nothing. If the room is at 55 deg F then it does not even need to have the compressor running to pass that inspection! Across the coil temps are way more useful but only as an indication. Inverter A/Cs ramp the compressor speed up and down so these temps will constantly be changing.

Outlet temp will vary depending on cooling capacity and airflow so if the compressor is at full speed and the evaporator fan on low speed or super quiet then 7 deg C is possible especially if the filter and/or evaporator are dirty.

"I am also disappointed by daikin inverter, is this system too new and makes problems ?"

Inverter A/Cs have been around for a long time but not so long for domestic use. If installed and maintained correctly they are excellent. However Thailand does not have the expertise to work on them so you can end up with problems that would not occur with the non inverter types. They are far more complicated and parts such as the inverter PCB are very expensive.

"I'm using an 18K Inverter (Toshiba) in my 35sq.m bedroom and cools it just fine. But note, Inverters take much longer to cool a room compared to non-inverters. When I turn on the aircon if room temperature is say 30C it will take about 2 or 3 hours to get it down to 22C"

Inverter A/Cs will cool just as well as non inverter A/Cs if they are rated the same (ie same BTUs) but will slow down as they approach the set point.

I have gone with an inverter system in my house but I will not let another cowboy near it if at all possible. On my next trip to Thailand I will have to correct the mistakes/short cuts the installer made -

No earth fitted even after asking for it

Inter link wires twisted together and taped to extend them

Drain has no fall even after pointing out before the holes were drilled that he was trying to make it run 100mm uphill!

Drain hose extended with ribbed pipe so will block easily

Short of gas

Like a lot of people I bought it knowing it is "undersized" but as it is for a bedroom and will not have to go below 24 deg C it will do the job and keep the bills down.

Edited May 24, 2015 by chang1

[Anthony5]

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

this temperature depends on the prevailing room temperature and can vary a lot. no 12k unit has an outlet airflow of 7ºC when switched on in a room which warmed up to 28 or 30ºC.

What is my prize Naam?

[bankruatsteve]

As it says in the link you post Some experts argue, some can argue about everything but I doubt that if it should be 55 degF that it will be double or half that figure if the move the thermometer a bit. I know that my 12000 Btu Daikin inverter units blow 7 degree Celsius in front of the outlet of the indoor unit

this temperature depends on the prevailing room temperature and can vary a lot. no 12k unit has an outlet airflow of 7ºC when switched on in a room which warmed up to 28 or 30ºC.

Will you agree and offer apologies if I take the test and post a picture of the thermometer?

If I don't get the 7°C or thereabout I will offer the same.

Don't know about Naam, but I'll take the bet. I don't think so.