Samsung AQV12VBAN low heating capacity

[Vasilis]

I use a Samsung AQV12VBAN for heating a 4 x 4 x 3.4 meters room ... (16 sq. meters).The aircon is installed at a good position / height so the air can be dispersed evenly inside the room.

i turn it on having an inside temperature of 12 degrees C and i can see the temperature reading on the a/c panel increasing quickly.It reaches 26 degrees in matter of minutes ...but the actual temperature inside the room is not even 18 degrees C . (measured by an accurate thermometer) . I know that hot air travels upwards but is this difference normal ?

With outside temperatures of around 10-12 degrees C , i cannot heat the room enough to feel warm despite what the panel says .Even when the panel reports a room temperature of 30 degrees C , the actual room temperature is around 20 C .

The house is old and it is not well insulated but i was under the impression that a modern 12.000 BTU inverter a/c would be sufficient for a 16 square meter room , especially when the outside temperature is around 8-10 degrees C .I have never felt hot enough inside my house despite what the AQV12VBAN says on its panel

Hot air is coming out of the unit but ,apparently , it is not hot enough. (?)

Do you think there is sth wrong with the unit ?

PS
I have two units installed in identical rooms and the situtation is the same in both of them

[back2space]

First of all a couple of things.

Does the temperature of the air on the unit read the same as your thermometer when you turn the system on, before it starts blowing warm air? If it does read the same then the thermister is working ok and you have a problem with warm air being pulled back into the unit.

The louvre should be pointing down towards the floor in heating mode, not across like it does in cooling. This is to force the warm air down towards the floor. The problem with wall units is that the warm air rises then the units sense warmer air at ceiling level and think its warmer than it really is. The only problem to resolve this is by placing the return air thermister outside the unit in the same place in the room you would put a room thermostat. Then the unit senses are temperature in the room rather than at the unit.

[Vasilis]

Thanks for the input.

When i turn on the a/c , the temperature difference between the panel reading and the pocket thermometer is 1-2 degrees C ...the a/c starts heating ,reporting a room temperature of 15 degrees ...in 10 minutes or so , it reads 26 degrees and then the rise of temperature is slower or nil (on the remote , i ask for 30 degrees C) .When the panel reports 26 degrees , the thermometer is showing 18 degrees or sth . Isn't this a big difference to be justified by the installation height of the a/c ?

Let's forget the readings etc ...with outside temps of 10-12 degrees C and provided that we operate the a/c with max heating settings , what would be the expected true temperature that a 12.000 btu inverter a/c should achieve in a 16 sq meter room ?

Furthermore , on the manual it says that ''... when outside temperatures are close to 0 degrees C , the heating capacity can drop up to 80-90% ''
So :
If i can't get warm enough (let's say a true mean temperature of 20-22 degrees) when the outside temp is around 10-12 degrees , then i assume that when the outside temp is around 0 degrees, the a/c will work for nothing ...so what's the story with the inverter technology being able to operate at very low (even below 0 degrees) temperatures ?

[nike123]

Clean your filters and, if necessary, wash indoor coil with adequate chemicals if they are dirty!
Then check again performance.

[nicolacozma]

Try to measure dT between return and supply air. If you can find also the capacity load of the compressor (operating frequency) this can help. You can also calculate the heating capacity of the unit. Q=m c dT. If this match the capacity table of the unit then the problem is not related to the unit.

[paul_h]

Filters clean?
louver pointed to blow air down and fan on high?

[Vasilis]

Filters are clean , the units are new (maybe 300 hours of operation in total)

I will give you an example :

I go to bed , set the a/c at 30 degrees C - high FAN , close all doors etc . I wake up after 7 hours and the panel displays a room temperature of 28-29 degrees.But i wake up covered in blankets

If the room temperature was in deed 28 degrees (believe me , here in Greece we know what heat is... ) , then i should wake up naked or sth.

The fact that ''heat rises to the ceiling'' would be a good explaination for the first 1-2 hours of operation.It is strange that a modern a/c cannot heat evenly (floor to ceiling) a room after 8-10-12 hours of operation at full capacity
At my previous house , i had a Fujitsu a/c 9.000btu non inverter that would turn a 12 sq meter room into an ''oven''

Anyway , i will call the Service company again ...units in warranty .

[sinewave]

Another leaky unit I reckon!


Should walk it no matter which way the louves are pointing and the filters are clean'ish!

[back2space]

I think 2 faults either the the return air sensor is faulty and reading wrong temperature or there is warm air cycling.

You havent answered whether the louvre is pointing to the floor and if you have the fan on high speed to force the air to the floor.

Sounds to me that hot air is short cycling back into the unit. I have had that problem with my units that are installed at floor height and return air sensor at floor height also, it was sucking warm air back into the unit and giving wrong readings to the outdoor unit so this meant outdoor unit was cycling off or runnign too fast.

[nike123]

Filters are clean , the units are new (maybe 300 hours of operation in total)

I will give you an example :

I go to bed , set the a/c at 30 degrees C - high FAN , close all doors etc . I wake up after 7 hours and the panel displays a room temperature of 28-29 degrees.But i wake up covered in blankets

If the room temperature was in deed 28 degrees (believe me , here in Greece we know what heat is... ) , then i should wake up naked or sth.

The fact that ''heat rises to the ceiling'' would be a good explaination for the first 1-2 hours of operation.It is strange that a modern a/c cannot heat evenly (floor to ceiling) a room after 8-10-12 hours of operation at full capacity
At my previous house , i had a Fujitsu a/c 9.000btu non inverter that would turn a 12 sq meter room into an ''oven''

Anyway , i will call the Service company again ...units in warranty .

Check temperature with some alcohol thermometer (or Hg) at same place where is indoor room thermistor placed (most likely at indoor coil air inlet) and compare with reading on display. If you have more than 2°C difference, thermistor or indoor PCB unit is faulty. If not, than you have hot air recycling for some reason.

[Vasilis]

You havent answered whether the louvre is pointing to the floor and if you have the fan on high speed to force the air to the floor.

Yeah , louvre is pointing to the floor and fan on HIGH setting.

Although i don't exactly understand what '' hot air recycling'' is , is there sth that can be done to avoid this ? Is there a solution to this problem ?

I will try to find an alcohol thermometer in order to verify again the difference (which is for sure more than 2 degrees C) ...

[back2space]

[quote=Vasilis;133145

Although i don't exactly understand what '' hot air recycling'' is ,
to avoid this ? Is there a solution to this problem ?
quote]

Hot air recycling is where the hot air exiting the unit is sucked back into the unit before it has had chance to circulate round the room, hence you get the unit thinking that it has reached its set point when the room temp is no where near the set point.

Make sure you use digital thermometer instead of other type as they are not accurate.

[Vasilis]

Still waiting for the Samsung Service to visit me ...

I verified the a/c panel temperature readings with a brand new Eliwell temperature controller and the difference is 8 degrees C ...so sth is definitely not right.

Does anyone here have experience with Samsung AQV12VBAN model in heating mode ?

Let's say we have an outside temperature of 7 degrees C and the AQV12VBAN is installed in a 16 sq meters room of an old house with ''poor'' insulation in windows. What would be a realistic , true indoor temperature the unit should achieve after 2-3 hours of operation (+/-2 degrees) ?

[airefresco]

To me it´s sounds like the unit is a bit too big for the room. A 2.5kW unit would be more suited to a room of that size. Assuming of course the room isn´t made out of glass or anything.

When you are taking the temperature readings, are you taking them at the inlet grille of the unit, or just the room temperature?

[superswill]

on these models the return air sensor(this is linked to the display on the front) can often became trapped under the case,as this needs to be remove to wire this model,i would check that the small black sensor is in it place and not trapped any where else,as you the lift the cover,behind the right hand filter there will be a holder for it to sit

also try holding the small on/off botton at the bottom right of the indoor for 5 seconds this will put the system into a forced cooling test run,displaying any faults on the LED display

[back2space]

I am thinking a sensor problem, either way even if its oversized for the room it shouldnt be a 8C difference no unit would let the room become overheated by 8C.

Deffo a sensor problem!

[airefresco]

Until it is confirmed that temperature was taken at the inlet grille of the unit, you can´t be sure the unit is reading 8ºc difference. The fan is on high, so the air will be moved around the room quite quickly. Try the fan on low and see if it still 8ºc different.

[back2space]

Ive had problems with air short cycling back into unit on heating mode.

This was confirmed and now rectified with remote sensors.

This was due to units being oversized to the room so airthrow was just too much but was bouncing off the wall opposite and coming back into the unit.

[Vasilis]

Another weird thing :

I put the a/c on HEAT mode , FAN high and selected temperature max 30 degrees C .

After abt 2 hours the unit ''reaches'' the selected temperature on the panel (30 degrees C)

At this point i pressed the TURBO HEAT button , the unit blings and goes into TURBO mode.Surprisingly , i see the temperature reading on the panel dropping fast from 30 degrees to 25 degrees !! Then , it starts climbing again...
Isn't this weird ?

I need to get warm without installing a sofa on the ceiling . My alternative temperature meter is reading 18 degrees on the ''sofa area'' when the unit (1,5 meters higher) is showing 28 degrees or more

In any case , many many thanks for your attention and assistance ...i want to see what the Service team will say abt this problem.

The refrigeration engineer that installed the units some months ago insisted that 12.000 BTU is the correct size for my rooms (i have two identical rooms with two identital a/c units) for the following reasons :

1) i rely solely on a/c for heating
2) the 16 sq m rooms have high ceilings
3) the inverter aircons can adjust their operation to the area they are installed at (so there is no matter of oversizing(?))
4) the 12.000 BTU would operate in a more ''relaxed'' way than the 9.000 btu model which would be marginal for my room/house

I trusted him since he had no profit from the whole thing (i bought the units myself and he just installed them)

[nike123]

[quote]

Another weird thing :

I put the a/c on HEAT mode , FAN high and selected temperature max 30 degrees C .

After abt 2 hours the unit ''reaches'' the selected temperature on the panel (30 degrees C)

At this point i pressed the TURBO HEAT button , the unit blings and goes into TURBO mode.Surprisingly , i see the temperature reading on the panel dropping fast from 30 degrees to 25 degrees !! Then , it starts climbing again...
Isn't this weird ?

Something is wrong with your air distribution or fan is operating erratically. That need attention of service engineer and measuring of air flow of indoor units against technical specifications.
Could be simple as fan motor capacitor.

Or indoor coil temperature sensor is faulty and gives higher temperature of indoor coil to PCB then it is really the case, and unit goes in overload protection mode.

[back2space]

Any update on this???

[momo]

How high are your ceilings and at what eight are the units hung? Check the location of the thermistor probe (black bulb sensor under grill), is it isolated in some way from the heat of the metal fins inside ? Samsung - musical, but made economic in a variety of ways (!)

[back2space]

YOu need to try to relocate the sensor outside of the unit!

Perhaps just poke the sensor through the grill so that its in the actual air supply.

What if you measure the temperature of the air going into the unit by putting your "alternative" temperature meter up on the ceiling to see if its really 28C up there?

[rude]

Maby take a picture of your room and a/c so we can see how it is positioned in the room?

[sinewave]

[quote=momo;137312]How high are your ceilings[quote]


Cut & paste from the OP's first post...........

I use a Samsung AQV12VBAN for heating a 4 x 4 x 3.4 meters room ... (16 sq. meters).The aircon is installed at a good position / height so the air can be dispersed evenly inside the room.

[Vasilis]

I haven't yet found a solution to my problem ...the Service is poor and they come when they like to.

This is the situation right now :

One of the two AQV12VBAN has a leaking condenser and is loosing *****.They told me that they will replace the outside unit (let's see when)

The other one ,that still has a low heating performance, it is in ''perfect condition''. It is not loosing ***** and the Volt measurements are ok (so the four-way bull**** is not faulty) .This is what they claim.

I wanted to ask : what else might be wrong with a machine giving a low heating capacity ? if ***** and 4-way switch is ok , then everything is ok ?

[back2space]

You need to show them the situation and the displaying showing 30C when the room isnt 30C.

Have you done as we have advised you and taken a temperature reading at the air intake grille?

I quote

"What if you measure the temperature of the air going into the unit by putting your "alternative" temperature meter up on the ceiling to see if its really 28C up there?"

You need to do this. If its 28C up there then the unit is working fine but your having problems getting the air down to floor level.

[Vasilis]

If its 28C up there then the unit is working fine but your having problems getting the air down to floor level....

...with the solution being what exactly ?

I have a 13.000 BTU (heat) inverter a/c from a pretty well known manufacturer / 6 months old ,installed in a 16 sq meter room of Athens ,Greece (not Alaska or anything) and all i require is a mean room temperature of 23-25 degrees

The whole issue is practical ...i don't care what the temperature on the ceiling is . Should or shouldn't the unit be capable to warm the room evenly , even after several hours of operation at full power ?

Why should i always have to set the unit at max 30 degrees in order to get a room temperature of 20 degrees ? Yesterday noon time , the outside temperature was 14 degrees so i tried to see what would happen if i set a temperature of 22 degrees on the a/c : pretty much the same situation

I will insist : isn't there anything else that might be wrong ? I mean : the whole check a ref. technician can do is to connect the manometers and a volt-meter on the outside unit ?

[back2space]

...with the solution being what exactly ?

The whole issue is practical ...i don't care what the temperature on the ceiling is . Should or shouldn't the unit be capable to warm the room evenly , even after several hours of operation at full power ?

Because we need to establish if the unit is thinking its reached temperature or if the ceiling area is reaching that temperature.

A number of different faults that there could be. If the unit is thinking its reached 28C when the ceiling area might not be 28C then this is a problem with the sensors.

If the ceiling area is at 28C then its a problem with the air getting down to floor level which I dont think would effect it that much by 28C, maybe a few degrees C warmer at ceiling level.

If this is the case then a ceiling fan would help get the air down to floor level.

But you must conduct this test before we can comment any further rather than saying you dont care what the temp is up there. But in actual fact you could because that could be your reason for the heating problem.

Have you also tried poking the sensor out of the front of the grille so that it reads the room temp? This has been asked twice now and you have not responded.

[Vasilis]

Look ...

First of all , i don't want to mess myself with sensors etc.Units are under warranty and i don't want to do sth wrong.

In regards to the actual temperature on the ceiling , i will go ahead and measure it right now ...I will use an Eliwell temperature meter (which is damn accurate)... although this is not covering my real problem :

Let's say that the sensor is working properly and the actual ceiling temperature is the one displayed on the panel ...What's the next step ? Making my house look like a circus with ceiling fans ? On the AQVBAN manual mentions nothing about ceiling temperature etc etc . It says ''ROOM'' temperature and this is what i am supposed to control by using the remote.

If there is in deed a sensor problem , then the technicians that came should check it out ...that's their job .Instead , they just said '' ***** is ok , volts are ok ...everything is ok''

Of course , it is quite possible that the unit itself is rubbish.

[back2space]

the temp you set on the remote is the room temp as your manual states. Where it gets the room temp is in the grille at ceiling height. So this is where your best checkin temp from. I do not think its a problem with air distribution but a sensor problem. And if the installers have not checked the return air sensor in the indoor unit then they cannot say it is operating properly. You say they have checked the out door unit but this is not the problem its your indoor unit that is saying its warmer than it is and this is why your room is not gettin warmer because of the false readings. Your temp reading at ceiling level will confirm this as its at the same height as the sensor inside the unit. Usually you will get slightly warmer ceiling area in any room as warm air rises you may have to compensate for this by setting the controller to 24c if you want 22c. But you shouldn't have to set to 30c to get 20c unless you have 20ft high ceilings which you don't!

[Vasilis]

Last night i measured the temperature high on the celing right next to the a/c inlet.Also took measurements at 1,5 meters above floor .I used a calibrated Eliwell 915/c.

-Temperature set on the remote : 30 degrees / max fan
-Initial temperature reported by Samsung : 15 degrees
Twenty minutes after commencement :
-Samsung panel : 28 degrees
-Eliwell reading at ceiling level (next to a/c inlet): 24deg
-Eliwell reading at 1,5 meters above floor : 19.8
-Eliwell reading outside the house : 14 degrees

[nike123]

Last night i measured the temperature high on the celing right next to the a/c inlet.Also took measurements at 1,5 meters above floor .I used a calibrated Eliwell 915/c.

-Temperature set on the remote : 30 degrees / max fan
-Initial temperature reported by Samsung : 15 degrees
Twenty minutes after commencement :
-Samsung panel : 28 degrees
-Eliwell reading at ceiling level (next to a/c inlet): 24deg
-Eliwell reading at 1,5 meters above floor : 19.8
-Eliwell reading outside the house : 14 degrees

It looks like Samsung reading is influenced by heat of heat exchanger (lack of air flow and/or placement of sensor to place where heat of exchanger is radiated to sensor) or temperature sensor is faulty.

Second, difference of 4K between 1,5m height and air conditioner height tells us that either some portion of heated air is recirculating, air speed is low and not directed to floor and/or unit is placed at to high position. Normal difference is about 2K

Usually air outlet should be placed between 2m and 2,5 m height.

Could you make photo of unit position on wall and photo of air sensor placement and post here?

Also you could place eliwell sensor on same place where unit sensor is, to check if he read OK?

[back2space]

-Initial temperature reported by Samsung : 15 degrees

What was the initial temperature on your Eliwell at ceiling height when samsung read 15 degrees? Was it also 15C?

If the reading is the same then your return air sensor in the unit is working correctly. If not could be two things wrong with sensor:

1. Sensor inside unit calibrated incorrectly inside air conditioner.
2. Sensor is touching something warm inside the unit (the hot coil) usually these are placed against the coil but should not be touching and this is effecting the temperature readout (4 degrees increase from ceiling height temperature)

And lastly you seem to be having big problem of getting the heat down to 1.5mtr height. With the fan on high speed as you state the air flap should be pointing down so if you stand under the unit you should feel the warm air blowing down at you.

Can you confirm if the flap moves down to the floor when you put the unit into heating mode. On cooling mode the unit will blow the cold air across the ceiling as cold air is naturally heavier than warm air which rises and stays at ceiling level. This is why in heating the unit must blow the hot air down to the floor.

If the unit is blowing to the floor then the unit is either undersized for the room or you have doors in the room open.

Report back with the answers.

You should be mentioning all the above to the installers and see what answer they come back at you with. They are in the same trade as ourselves.

[Vasilis]

Here attached is a room picture ...a square room with one door and two windows.I could not get a better picture but you can see the ceiling , floor , walls (i am taking the photo with my back on the forth wall -not apparent on the photo).

The unit is blowing air at full fan speed and in almost vertical direction at all times when in heat mode.

When i stand below the unit , i can feel hot air blowing from the unit but i don't know if it is hot enough (it is bearable for sure).

I cannot place the eliwell exactly where the a/c sensor is ...i will give it another shot now (and i will also check if the samsung panel and eliwell report the same temperature during start up)

Maybe the units are undersized ...maybe another brand of a/c would be better . But i have to exhaust all other possibilities before switching to another heat source.All technicians i spoke to ,agree that 12.000 BTU inverter should be more than enough for a 16 sq meters room.

[nike123]

Remove that curtain below and check for any difference in room temperature after 30 min.
Also if room height is 3,5m than indoor unit is placed to high (air outlet at cca 2,8m).
These two thing could explain temperature difference of 4K at 1,5m height and at ceiling level.

[Vasilis]

I took some measurements again :

A/C outlet to floor : 2,51 meters
Floor to ceiling : 3,20 meters exactly (for some reason i got this wrong in my first post).

Oh , many thanks again for your time and assistance !!

[back2space]

Remove that curtain below and check for any difference in room temperature after 30 min.
Also if room height is 3,5m than indoor unit is placed to high (air outlet at cca 2,8m).
These two thing could explain temperature difference of 4K at 1,5m height and at ceiling level.

When you took this picture was the unit turned off or on as the air flap looks to be horizontal it should be further down.

[back2space]

I took some measurements again :

A/C outlet to floor : 2,51 meters
Floor to ceiling : 3,20 meters exactly (for some reason i got this wrong in my first post).

Oh , many thanks again for your time and assistance !!

Can you do the temperature reading for us when the unit is first turned on etc with the other temperature device.

If you look under the filter cover too where the filter is look at the coil there should be like a black probe on a wire that is secured to the coil, check that this is not touching the coil directly at the end.

[Vasilis]

Just did that :

Eliwell at A/C start up : 14 degrees
Panel at start up : 16 degrees

The temperature probe of the a/c unit is in place (there is a designated plastic socket where it is tight fitted)

[back2space]

Ok so already there is a 2 degrees difference. There should be no difference at all.

Your sensor appears to be out of calibration

Now one thing to try to see if anything different happens. You can unclip the probe so it is loose, you wont damage it, you need to just poke this outside the front of the grille through the filter so it is away from the coil.

Repeat the test 10minutes later see if the temps have equalised.

I had to remove the probe from my unit to the front of the grille until I had a remote sensor fitted as the unit was sensing the colder temperature of the floor area. I have floor units mounted at floor height you see.

Either way you need to get the installers back out explain the problems of the temperature difference. also that the air is not getting heat down to lower parts of the room.

Either they have undersized it but a solution needs to be found.

[Vasilis]

Thanks back2space ...

I will try this tommorow morning (although the probe cable does not look long enough).

Anyway , the technicians are comning tomorrow to install the new outside unit of the other AQVBAN that was leaking *****.I will probably show them this thread

[back2space]

Make sure you explain exactly as we have said everything to you.

Show them what the unit is doing get them to spend time there, do not let them give you any rubbish excuses. I had problems recently with mine has taken me since August to get the probelm sorted only now has the installer believed there is a problem.

Do not let them give you bull$hit!

The sensor is faulty and the unit is not getting the air down to ground level. They probably need to check the air temperature coming out of the unit to see how hot it is.

[Vasilis]

Good morning ,

Last night i fell asleep with the eliwell next to me.

After 12 hours of continuous operation with the a/c set as follows :

30 degrees HEAT mode / full fan speed / air grille at vertical position .

I woke up and the samsung panel was reporting 30 degrees and the eliwell (placed next to my bed on a table) was reporting 22.2 degrees.

So the whole globe climate zones can be found in my house

[nike123]

Good morning ,

Last night i fell asleep with the eliwell next to me.

After 12 hours of continuous operation with the a/c set as follows :

30 degrees HEAT mode / full fan speed / air grille at vertical position .

I woke up and the samsung panel was reporting 30 degrees and the eliwell (placed next to my bed on a table) was reporting 22.2 degrees.

So the whole globe climate zones can be found in my house

Is it nice to sleep in space of 22°C temperature?
I would woke up groggy. To me, 16°C in winter is nice sleeping temperature.
You are big contributor to global warming of mother Earth

[Vasilis]

That's exactly my problem Nike (you are not off topic)

In few words , i cannot set the desired temperature on this unit . Last night , i set it to 30 degrees and i got 22 degrees on the bed area.

What should i do every night before i go to bed ? measure the outside temperature , calculate the difference between panel reading and actual temperature in bed height and set it accordingly ?

I would expect from the unit to set it at 22 degrees and get an anerage room temperature of 19 degrees ....but this is not the case

[back2space]

Vasilis... rather than keep repeating the same problem over and over again to the forum you need to take action and speak to the installers or the manufacturer.

[Vasilis]

Fingers crossed , i found out what the problem was ...i will run some tests myself but the solution lies on the answers above.Actually , both the actual cause and the cause of the cause are mentioned in this thread

I will let you know tomorrow for sure ...so far i managed to get the actual temperature up to 25 degrees at the rock bottom floor !! (with the samsung panel reporting 27 degrees which is what i always wanted)

I start to like my samsung machines again !!

[back2space]

Fingers crossed , i found out what the problem was ...i will run some tests myself but the solution lies on the answers above.Actually , both the actual cause and the cause of the cause are mentioned in this thread

I will let you know tomorrow for sure ...so far i managed to get the actual temperature up to 25 degrees at the rock bottom floor !! (with the samsung panel reporting 27 degrees which is what i always wanted)

I start to like my samsung machines again !!

Dont keep us in suspense like this! What was the problem with it? Was it the fact the flat wasnt pointing down far enough??? Or was it something else I mentioned?

Probably the air probe inside the unit touching something warm.

[Vasilis]

Dont keep us in suspense like this! What was the problem with it? Was it the fact the flat wasnt pointing down far enough??? Or was it something else I mentioned?

Probably the air probe inside the unit touching something warm.

It's not a matter of suspense ...i just wanted to make sure that this was the problem.

Here we go :

The whole problem was an installation one : both units were installed right above the curtain (stick) . The second one on the other room (not appearing in the photo above) is installed even closer to the curtain stick.

Nike(123) , you just did it !

If you see one of my posts above , you will see that when i gave the TURBO order with the remote , the temperature on the samsung panel was dropping fast.

So : when i was operating the units with the grille in almost vertical position (which is sth i always did) , the hot air was bounching on the curtains/curtain stick and returned back in the unit messing the performance and the samsung temperature sensor . When the unit is set at TURBO mode , the grille automatically turns to a 45-60 degrees angle (by design) , which explains why the samsung temperature reading was droping at turbo mode (the hot air was no longer returning back to the unit since there was no bounching on the curtain stick at this grille angle)

As soon as i dismantled completely the curtains and stick , the eliwell temperature reading has risen like crazy ...i could n't believe it !

The whole curtains obstruction was not obvious ...the vertical position of the grille is doing the right job but at this angle ,all this time, it had a negative impact on the operation of the units.

Of course , the curtains were installed before the a/c units so the installers didn't take this factor into consideration.

Many thanks to all of you ...for the advice and support and i apologize if i made you bored or anything