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  1. #1
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    What you wanted to know about Air conditioning but were afraid to ask

    What sort of system should I buy?

    SPLIT SYSTEMS.
    The most common form is a split system with an indoor unit and an outdoor unit coupled together with two pipes and a communication and supply cable. They are simple systems and can be installed in less than a day. The indoor (cooling) coil is designed to do one room only so if you are thinking of getting a larger sized unit to do two rooms do not waste your money you will have one room at 21C and the other at 31C. If you wish to do more than one room you will need a multi head unit (one out door unit running two to four indoor units). These units have an inverter which varies the speed of the A/C compressor to suit the load from the indoor units. Advantages are One (albeit larger) electrical supply required for the outdoor unit. Disadvantages are one fault in the outdoor unit and all indoor units are out of service. A much more complex pipe run and therefore, has the potential for more leaks. Repairs out of warranty are more expensive. A large compressor is running a small load when only one indoor unit is required. They are made to recirculate room air and their is no allowance for fresh air.
    Single indoor unit systems for each room means only one smaller system runs per room cooling and will be cheaper to run. Breakdowns only affect one room. Out of warranty repairs are less complex and cheaper. One common problem of both is that indoor units need to be installed on outside walls so that the unit can naturally drain the condensate to outside. Units generally should be installed on the centre of the wall for even air flow. Units installed on inner walls will require a small water pump to drain the water through the ceiling space to outside or directly on to the roof. The filter should be cleaned once a month and the evaporator with a foam cleaner every twelve months at least. The outdoor unit should be installed on a wall out of direct sunlight with plenty of ventilation preferably away from soil and dust.

    DUCTED SYSTEMS
    Ducted systems are more commonly used in commercial buildings or larger houses where rooms are extremely large or multiple rooms are cooled at the same timeand are generally considered uneconomical in the smaller sizes. They are more expensive to install and maintain. Ducts are usually round flexible or rectangular sheet metal and insulated. They should be coated in tropical climates with a mould and fungus inhibitor which also helps with odour control. These systems can modulate a certain amount of fresh air into the building to prevent stale air. The fresh air can be set at a constant air quantity or can be modulated with a CO2 monitor for more efficient operation. The fresh air duct can also be modulated by temperature to take advantage of cooler night time temperatures in temperate areas allowing for less outdoor unit operation and greater efficiency gains (often referred to as an economiser). Ducted systems generally allow for more sophisticated air filtration and therefore can deliver a better overall indoor air quality than a standard split system. Air return will be required in each room either by ceiling return or appropriately sized door or wall vents. Where possible the ceiling space can be utilised as a return air plenum which saves money on running multiple return air ducts to each room. Each varying room load is controlled by an adjustable air volume damper and a separate room thermostat strategically located. More efficient systems have electronically controlled variable air volume dampers (VAVs) which help decrease energy costs. Zone control can be installed to isolate areas that are not being used. Supply air registers are round square or rectangular and are strategically place to prevent dead air pockets. Slot diffusers are often required above large glass areas with a high solar load. A higher amount of maintenance is required due to the ductwork, filtration and extra complexity and therefore higher maintenance costs.

  2. #2
    Days Work Done! Norton's Avatar
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    Quote Originally Posted by Hugh Cow View Post
    What sort of system should I buy?
    Split. Samsung.

  3. #3
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    ^^ Good idea if you like installing shite.

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    Thailand Expat cyrille's Avatar
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    The filter should be cleaned once a month and the evaporator with a foam cleaner every twelve months at least
    Christ, looks like the missus needs to get cracking.

    48 months worth

    (Mitsubishi EconoAir )

  5. #5
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    Maybe your local air is a tad more pristine. The above was meant for high pollution areas. Mitsus are quite popular in Oz. Mainly due to a fat Oz ex cricket captain.

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    Thailand Expat cyrille's Avatar
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    Quote Originally Posted by Hugh Cow View Post
    Maybe your local air is a tad more pristine.
    Chiang Mai.

    Cleaning the filters should be straightforward. Cleaning the evaporator looks like it could be a faff.

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    Nice one Hugh. I suspect most get their filters cleaned annually. Takes me back your comment on another thread where you said you always check the filters in your hotel rooms, which gave me a smile but actually i dread to think what most are hiding. Like the idea of trying to do it myself and will give it a go when next over, i rarely use ours and a fans seems to be enough most of the time.

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    Thailand Expat David48atTD's Avatar
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    I have (in the West) a Mitsus split system ... more then a decade old.

    Never re-gassed, never cleaned/replaced a filter. Is there a special place in Hell for me?

    Hail Mary

    Hail Mary

    Hail Mary

  9. #9
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    Quote Originally Posted by cyrille View Post
    Chiang Mai.

    Cleaning the filters should be straightforward. Cleaning the evaporator looks like it could be a faff.
    There is a foam spray that you can apply directly to the coil and the actual condensate on the operating cooling coil washes it away down the drip tray and drain line. It also cleans the two on its way out. Available from refrigeration and air conditioning wholesalers in Chiang Mai. There are other coil cleaners not foam. One if I remember is blue in a squirt bottle and does the same thing and is reasonably priced. You could call in the service agent and have it professionally cleaned if you have one you trust. In Bangkok it costs under 1000 baht all up as a price guide.
    Last edited by Hugh Cow; 28-05-2019 at 06:34 PM.

  10. #10
    Thailand Expat cyrille's Avatar
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    Thanks.
    I'll look into it on that modern day oracle youtube.

  11. #11
    lom
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    Quote Originally Posted by Hugh Cow View Post
    There is a foam spray that you can apply directly to the coil and the actual condensate on the operating cooling coil washes it away down the drip tray and drain line. It also cleans the two on its way out. Available from refrigeration and air conditioning wholesalers in Chiang Mai.
    It doesn't clean the fan though..
    Hot/dry season here has loads of fine sand dust in the air so I take out the filters every 2nd month and clean them. We have a guy coming every 6 month to high pressure water clean our indoor and outdoor units and refill gas if needed.
    400 baht per aircon twice a year saves more than so on the electric bill.
    May the bridges I burn light my way

  12. #12
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    Quote Originally Posted by lom View Post
    It doesn't clean the fan though..
    Hot/dry season here has loads of fine sand dust in the air so I take out the filters every 2nd month and clean them. We have a guy coming every 6 month to high pressure water clean our indoor and outdoor units and refill gas if needed.
    400 baht per aircon twice a year saves more than so on the electric bill.
    Not worth doing yourself at that price.

    Some people remove the fan barrel completely and clean it. In some brands they come out easily while in others they are a nightmare to remove. Unfortunately I cant tell you which is which as my experience tends to be only on large commercial systems.
    Last edited by Hugh Cow; 28-05-2019 at 07:55 PM.

  13. #13
    lom
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    Quote Originally Posted by Hugh Cow View Post
    Some people remove the fan barrel completely and clean it.
    Yes, that's what our guy does.

  14. #14
    Days Work Done! Norton's Avatar
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    Quote Originally Posted by lom View Post
    It doesn't clean the fan though..
    Hot/dry season here has loads of fine sand dust in the air so I take out the filters every 2nd month and clean them. We have a guy coming every 6 month to high pressure water clean our indoor and outdoor units and refill gas if needed.
    400 baht per aircon twice a year saves more than so on the electric bill.
    Do exact same here. Price 300 baht. Isaan a bit cheaper but plenty of fine dust so clean filters monthly. A 15 min job.

  15. #15
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    Quote Originally Posted by Hugh Cow View Post
    What sort of system should I buy?
    Daikin all the way

    lol...OK... its a personal choice. I did the research and there are one or two good and reliable brands. I got a deal.

    More important is specc'ing the right-sized unit for the room you are trying to cool. Undersize and it will labour continuously. Over sized and they will cool the room too quick, leaving the moisture in the air which will become clammy.

    The Daikin units i chose have the latest R-32 refrigerant, more economical in its cooling and with less effect to the environment and global warming. OK im not arround in 100 years to see the benefit of using low impact refrigerant , but nor was Humphry Repton to see the Park setting he laid out at the Henham Estate in Suffolk. I like to think im a bit responsible for he future.

    What also pulled me to the units i picked was... they are wi-fi linked meaning you can activate individual units remotely through the mobile if, say you are arriving back and the units are off.

    Hope this helps the debate...

  16. #16
    disturbance in the Turnip baldrick's Avatar
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    https://www.lazada.co.th/products/da...470388694.html

    how many cubic meters could I expect this to cool ? downstairs in a cement block house

    and if I installed heavy curtians to cut off some of the downstairs area to keep the size useful , is it likely to work ? - the loungeroom , kitchen and stairwell are all connected and open , so I wans thinking to just curtian off the lounge

    I expect it to be rather hot this summer

  17. #17
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    Another issue to consider for AC's is condensation. Had an issue last year where I thought I had a leak in the roof because I had water dripping through the daughters bedroom ceiling. Had a builder try everything to stop the lead but he never could. Turned out to be the AC copper pipes that are running through the roof were sweating with condensation from the humidity. All 6 split system units have the compressors mounted in banks of three on walls that are away from outdoor living areas. This means the copper pipes have been run a long way from the indoor units to the outdoor units. The installer used the common insulated wrapped on the pipes but this didnt insulate the cold pipes from the humid air, so just end up with water condensing and running along the pipes until it hits a low spot and drips onto the ceiling.

    The only remedy for this was to have all the wrapping on the pipes removed, pipes disconnected and proper black tubular insulation installed on each pipe independently. Big job that was labour intensive. I think each person that was up in the roof must have lost 5kg's each in sweat doing that job. After that no issue with dripping water.

    Keep this in mind if you have run pipes in your roof space.

  18. #18
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    Quote Originally Posted by Norton View Post
    Split. Samsung.
    Never again. Mine caught fire recently. Piece of shit.

  19. #19
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    Quote Originally Posted by baldrick View Post
    https://www.lazada.co.th/products/da...470388694.html

    how many cubic meters could I expect this to cool ? downstairs in a cement block house

    and if I installed heavy curtians to cut off some of the downstairs area to keep the size useful , is it likely to work ? - the loungeroom , kitchen and stairwell are all connected and open , so I wans thinking to just curtian off the lounge



    I expect it to be rather hot this summer
    That unit will do approx 34 sq metres. Remember air throw is important. If there is a very large area it may require 2 units to prevent dead spots. As stated previously they will only do one room with no partitions effectively. Some cool air will filter into the stairwell but the air will stratify and you will feel the heat as soon as you go up a few stairs. An extra fan will help but may not improve it that much. Send a room dimension diagram if you want a more specific answer.

  20. #20
    Your local I.Q. Monitor
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    Quote Originally Posted by skidley View Post
    Another issue to consider for AC's is condensation. Had an issue last year where I thought I had a leak in the roof because I had water dripping through the daughters bedroom ceiling. Had a builder try everything to stop the lead but he never could. Turned out to be the AC copper pipes that are running through the roof were sweating with condensation from the humidity. All 6 split system units have the compressors mounted in banks of three on walls that are away from outdoor living areas. This means the copper pipes have been run a long way from the indoor units to the outdoor units. The installer used the common insulated wrapped on the pipes but this didnt insulate the cold pipes from the humid air, so just end up with water condensing and running along the pipes until it hits a low spot and drips onto the ceiling.

    The only remedy for this was to have all the wrapping on the pipes removed, pipes disconnected and proper black tubular insulation installed on each pipe independently. Big job that was labour intensive. I think each person that was up in the roof must have lost 5kg's each in sweat doing that job. After that no issue with dripping water.

    Keep this in mind if you have run pipes in your roof space.
    Correct. Pre insulated pipe is used because it is much cheaper and less labour intensive.
    If in a roof space in the tropics a minimum 19mm pipe insulation should be used. It normally comes in 2 metre lengths so the joints should be sealed with contact adhesive and then wrapped with duct tape. The insulated pipe should be laid so that the insulation is not compressed, otherwise the insulation will be compromised. The insulated end of the pipe at the outside unit end should be sealed with a good silicon. When operating the cool pipe creates a low pressure air film between the pipe and insulation which draws outside humid air towards the colder indoor unit. Over time if this is not done, this humid air passing between the pipe and the insulation eventually saturates and will then drip onto the ceiling. The silicon helps prevent air ingress.

  21. #21
    Your local I.Q. Monitor
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    Quote Originally Posted by David48atTD View Post
    I have (in the West) a Mitsus split system ... more then a decade old.

    Never re-gassed, never cleaned/replaced a filter. Is there a special place in Hell for me?

    Hail Mary


    Hail Mary

    Hail Mary

    No but there is in the hospital. Just follow the COPD or Tuberculosis signs to the ward.

    BTW a squeaky clean filter is not the most efficient. As particles pass through the filter which has varying size holes for the air to pass, the large holes allow smaller particles to pass through. As these large holes get blocked by larger particles, the air is forced through the smaller holes gradually trapping finer particles until the air gets too restricted through the filter and the filter should then be cleaned or changed, as the airconditioners efficiency to cool has now dropped due to poor airflow.
    Last edited by Hugh Cow; 29-05-2019 at 12:21 PM.

  22. #22
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    I couldn't edit my post so just a little thing to remember.
    The more humid the weather the bigger the air conditioning heat load.

    The specific heat of one kg of dry air is approx 1 kilojoule per kg per C
    E.G If you want to cool 10 kg of dry air from 35C down to 20C it will take 1 X 10 x 15 = 150 kilojoules of heat to be removed.

    If that air contained 100 grams of water vapor per kilogram of air we would need to remove the water by condensing it on a cold coil. The energy or latent heat of condensation required is 2500 kilojoules per kilogram of water.
    Therefore: 100grams of water X 10kg of air X the energy to condense the vapour back to water at 2500 kilojoules per kilogram = 0.1 k/g water X 10 kg air X 2500 kj/kg (Latent heat of condensation) = 2500 kilojoules

    From the above you can see that as the humidity increases, the amount of water in the air increases and so the cooling load increases much more dramatically from the humidity (percentage/weight of water in the air) than just the increase in air temperature.
    Hope that wasn't too technical to get across the point. I did try to simplify it as much as possible.

    N.B. Joules are a unit of energy and Watts are a unit of energy over time, therefore 1 watt = 1 joule per second

  23. #23
    Days Work Done! Norton's Avatar
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    Quote Originally Posted by Humbert View Post
    Never again. Mine caught fire recently. Piece of shit.

    Never here but as Thai Dup says mostly a matter of personal choice. Daikin is quite good as well. Never heard of one catching fire. However, Daikin have been known to explode. Must be so. Saw it on the internet.

  24. #24
    Your local I.Q. Monitor
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    Quote Originally Posted by Norton View Post

    Never here but as Thai Dup says mostly a matter of personal choice. Daikin is quite good as well. Never heard of one catching fire. However, Daikin have been known to explode. Must be so. Saw it on the internet.
    Some refrigerants now used in airconditioners are flammable, with R32 in the lower classification of A2L. The upper and lower flammability limits are between 14% and 30% of air by volume. Therefore the unit should be sized such that any leak will be outside of this range in comparison to the room volume.

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    Does anybody know what this is ? it's leaking from 2 identical ACs , this thread inspired me to try and clean them properly.It's very sticky.


    on further inspection it looks like its something to do with the circuit board where the indicator lights are.Its some kind of jelly coating the circuit board which appears to be melting ? any ideas ?
    Attached Images Attached Images
    Last edited by parryhandy; 29-05-2019 at 01:49 PM.

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