Aircon Fault Symptoms

Aircon unit is Blinking Light

<!-- -->There are a few common scenario that will cause your air conditioning unit to switch off automatically:

  1. Aircon Unit is blinking light – This means there is an error in your AC system 
  2. Aircon Unit switch on, run for awhile and switch off automatically – This means your gas pipe thermistor might be faulty 
  3. Aircon Unit is overheated and cause the compressor to switch off – This means your outdoor unit is fully choke with dirt and cause it to overheat

<!-- -->

Aircon is leaking water

<!-- -->If your air-conditioning system is leaking water, it could be cause by a few scenario,

Your aircon system has been in use for a few years,

  1. Drain pipe is choke with jelly and dirt thus causing back flow of condensate and dripping out of your aircon unit
  2. The indoor unit is so dirty that it chokes up the internal drain line and cause the blower to spit water out of your aircon unit
  3. There is icing forming on your indoor unit, causing water to drip. This is cause by low pressure of the system which has a possibility of gas leaking

Your aircon system is new and only has been in operation for a few months,

  1. There is insufficient gradient on your drain pipe, your installer might have install it wrongly.
  2. Your drain pipe is connected wrongly
  3. Your drain pipe has crack and causes a leak
  4. The drain pipe is not insulated and causes condensation at the bottom of your Indoor Unit

 <!-- -->

Aircon Pipe Leaking Gas

<!-- -->Most aircon leak are not easily detected as small pin needle leak will take a long time before you noticed it. Freon gas is odourless and is poisonous when you inhale in big quantity, it is always important to prevent it before it could get worst.

Below are the following symptoms you should take note.

  1. Loss of cooling power, you start to feel that your aircon is getting warmer day by day
  2. All your aircon indoor unit are not blowing out cold air
  3. Your coils are freezing and it causes water condensation which leaks from your indoor unit
  4. You have been topping up gas regularly because your aircon contractor told you that is normal. This is a false statement.
  5. If visual inspection is possible along the pipe routing, be sure to look out for stains as these are signs of a leak
  6. Lastly if the leaks is big, hear out for whistling sounds if any

Hoot smart monitoring device could also prevent this from happening. Contact us to find out more how you can implement this for your home and keep yourself safe!<!-- -->

Aircon Not Blowing Cold Air

<!-- -->When your aircon unit is not blowing out cold air, there might be a few causes.

  1. Weak airflow cause by dirty coil and blower that cannot generate enough cool air from the indoor unit
  2. If all aircon unit are not blowing out cold air, the compressor might be faulty or there is leak in your system
  3. If only one of your aircon unit is not cold, outdoor FCU thermistor sensor/expansion valve might be faulty.

No matter the cause, get it repaired by a professional aircon contractor to prevent worse aircon problems. Click on the whatsapp icon now to contact us!<!-- -->

Aircon Installation

Aircon Installation with Stainless Steel bracket for older HDB

<!-- -->For Home Owners who stayed in older HDB estate, they are required to find certified registered BCA contractor to install the stainless steel bracket. Hoot engages BCA trained installer for air-conditioner works. Please contact us for more information.

 <!-- -->

Recommended Thickness for Copper Pipe

<!-- -->There are 2 types of offering in the market

  • Gauge 22 or SWG22 which is 0.71mm thick
  • Gauge 23 or SWG23 which is 0.61mm thick

There are different grading and standard given to different pipe diameter of the copper pipes. The household air-conditioning system usually operate at a maximum of 330psi. The standard design of pipe thickness is 1.5 times the maximum pressure however the above specification marginally meets the requirement. But, the aircon system come with a high pressure sensor that cut off the system when there is a high operating pressure.

Thus using both SWG 22(0.71mm) or SWG 23 (0.61mm) is acceptable in market norms. We will definitely go for thicker copper pipe whenever possible.<!-- -->

Insulation Thickness for Copper Pipe

<!-- -->As a engineer, we can calculate the required thickness required for copper pipe insulation.

Assuming standard Air conditioning operation with an ambient temperature of 27 degree Celsius & 77% RH in the room, the requirement for insulation thickness would be minimally 10.5 mm to 12.6 mm for various copper pipe sizes. This translate to 1/2 inch thick insulation which is the current market practice.

So its not free upgrade of material from 3/8 inch to 1/2 inch, it should be standard offer for all AC models.


P.S. If you are in cold country with humidity that is lower, you can use 3/8 inch insulation. Singapore weather is just too hot! So overseas branded insulation doesn’t mean its suitable for Singapore climate. =)<!-- -->

Why is my pipe trunking so big?

<!-- -->Due to the market trend of offering upgraded material with 1/2″ thick insulation and 16mm Drain pipe with 1/4″ insulation. The trunking size for system 4 are usually 2 sets of 4″ by 3″ trunking. (Refer to picture on the right). So if contractors are offering you material with 3/8″ thick insulation and 13mm Drain pipe with 1/4″ insulation, you will notice that it is 2 inch shorter (Refer to picture on the left). Anything smaller than this means contractor are squeezing the material into the trunking which will cause condensation issue. Insulation should be lightly packed and not squeeze to ensure best performance of the insulation.

<!-- -->

Reuse of existing piping for replacement of aircon system

<!-- -->Aircon suppliers have all come out to say that the pipe can be reuse under certain conditions,

  1. Check condition of pipe by holding pressure for minimally 48 hours
  2. Flush clean the pipe to remove any dirt and contaminants.
  3. Engage professional contractor to perform the above

The recommendations are done mostly by people who have concealed piping in their walls, usually for those who stayed in condominiums. Replacing new piping will be costly as it require hacking and patching of the walls. Though they agree to the above and if you are planning to stay another 10-20 years in your estate. It is best recommend to replace a new set of piping. This can be done by laying it on the wall and covering it with trunking. Most of them would think is hideous but believe me, you will not even notice it after 1 month anyway.<!-- -->

Insulation Installation Guideline

<!-- -->Piping Insulation should always be individual. Only at the connection of the FCU is combine into 1 due to insufficient space at the back of the FCU.<!-- -->


Why is my aircon producing a foul smell?

<!-- -->There are two types of symptoms why your aircon is producing a foul smell.

  1. Air Con that smells like “smelly sweat” coming out the first 10 minutes but disappear after that
    • The condensation on the coil are not dripping off to the drain pan. The condensate sticks on to the coil and during the next round of operation thus causing the “smelly swear” smell

Solution: Turn on the mold proof function of your AC device, if you do not have this function, manually turn it on to FAN mode and let it run for 20 minutes to clear off any excess condensate. This helps to get rid of the smell. 

  1. Air Con that constantly producing a smelly smell (This usually happen after a long period of time)
    • There is a scent freshener in the room and during aircon operation, it get mixed in with the indoor unit and this get stuck on the coil
    • The drain pipe is choke with dirt or located near a place with pollutant or odour that is producing a foul smell, the air get sucks in and circulate into the room

Solution: You need to find the source of the problem first before performing a chemical wash as this will only temporarily remove the smell that get stuck on the coil. It will come back to you again after awhile. <!-- -->

Extended warranty? What you need to know before buying it

<!-- -->Extended warranty in the market have 2 types, please understand fully the terms and condition before going ahead.

  1. Warranty by Supplier/Manufacturer 
    • Usually covers all parts, labour and transports for the whole system.
    • Usually no hidden condition unless otherwise stated.
  2. Warranty by Retailer/Contractors
    • Usually cover parts but not labour fee and transportation fee.
      • Labour Fee: $80-$100/day
      • Transportation Fee: $50-$60/day
    • If cover everything, usually will request you to do servicing 4 times a year directly from them.

Always ask clearly if parts, labour, transport is covered in the extended warranty. Request for detailed black and white contract from them to protect yourself.

 <!-- -->

Why is my aircon not feeling cold?

<!-- -->There are multiple reasons and when your air con would not feel cold. Lets look into a few scenario.

  • When you recently purchase your NEW air-conditioner but you are feeling not cold enough 
    1. It could be undersize where your capacity is insufficient to meet the cooling load of your room
    2. It could be insufficient refrigerant that cause insufficient cooling to your room
    3. If you recently change from a non-inverter aircon to an inverter aircon, you might feel the cooling difference as non-inverter aircon runs at 100%
  • When only 1 of your aircon unit has been doing a good job but suddenly dies on you (The other indoor units are working properly)
    1. The thermostat sensor is faulty and giving a wrong signal back to your aircon system
    2. The aircon unit has not been service for a long period of time, it could possibly be choke with dirt and dust.
  • When all your air-con is not feeling cold
    1. The compressor has break down – check if the compressor is running by listening to it at the outdoor unit
    2. There is a leak in your piping and cause insufficient refrigerant gas to cool down the room
    3. Outdoor unit fan motor faulty
    4. Outdoor unit PCB faulty

 <!-- -->

Which is more efficient? Turn on 1 FCU or turning on 2 FCU in 1 system.

<!-- -->If you have 2 sets of A Scenario running, you will consume 1.18kW at the start vs B Scenario which consume about 1.28kW. However, in A Scenario, the minimum power consumption will be 0.9kW vs B scenario which is only 0.6kW

Most of the time, the unit will run lower than rated power consumption in the evening and night-time, thus Scenario B in the long run will have better cost savings!<!-- -->

Aircon Servicing

Why is my Indoor unit noisy?

<!-- -->There are a few possibility of the causes,

  1. Misalignment of fan motor, causing loud noise
    • Require general servicing to clean up indoor unit and grease motor
  2. Producing “hu hu hu” sound, this is cause by dirty coil that is choke.
    • Require chemical wash to purge out all dust and dirt in between the coils
  3. Crackling Sound cause by possibility of Expansion and Contraction of cooling coil
    •  Sound usually goes away after 15 mins of operation
  4. The blower sound at high fan speed is loud and affecting my sleep
    • Set to lowest fan mode to enjoy a quieter peaceful sleep.

<!-- -->

Why is my aircon leaking water?

<!-- -->There are a few reasons that why your aircon might be leaking,

  1. The gradient of the drain pipe is insufficient, thus causing water to flow slowly or even causing the water to get stagnant along the pipe. This will cause jelly to build up and then later cause a back flow of condensate out from your indoor unit.
  2. Your indoor unit is not tilted slightly to allow water from the drain pan to flow out to the drain pipe. In the long run when your drain pan is stuck with jelly and dirt, it will cause a overflow from your indoor unit.

If you experience this problems frequently, the only way is to get servicing done regularly to keep the drain pan and drain pipe clean so as to allow water to flow out smoothly. You may also use a clear choke tablet and place it in your drain pan so this would allow it to prevent forming of jelly.<!-- -->

Suction and Discharge pressure of Multi Split Aircon

<!-- -->

A normal operating range of aircon suction pressure ranges from 80PSI to 138psi. The discharge pressure ranges from 280PSI to 330PSI.<!-- -->

Aircon Repair

Why is my aircon coil icing?

<!-- -->If this happen, it has a high probability that your system has insufficient refrigerant. This causes the refrigerant gas temperature to drop below sub-zero. Contact us to perform a check on your system as there is possibility of leakage in your system and need rectification.<!-- -->

There is leak in your piping, what should you do?

<!-- -->This is the biggest headache that everyone faces, practically it is too costly to even fixed it.

  • Troubleshooting by holding 24-48 hours pressure to see where the leak is (Cost factor $500-$800 for 3-4 days job)
    • If there is a leak in the condenser unit,
      1. There is possibility that you may change the condensing unit if still available ($1500-$2200 to replace outdoor unit)
      2. There is possibility that you may repair the leak ($200-$300)
    • If there is a leak in the piping, it might seems not economical as you would need to dismantle the trunking covers to check where exactly the leak is. Not forgetting if you have false ceiling, you might need to hack it to check it. No contractors will go down this road.

There isn’t much you can do if your piping are concealed, at this point of time, is only to replace the whole system which has much more economical sense. So always go for experience contractors who has a lower chance of making such mistake.


 <!-- -->