FAQ for Aircon (Servicing & Maintainence)

I have decided to do up a FAQ for issues that aircon units commonly face.
These are for units that are in operation for a period of time, not for newly installed units.

Q.  Why my indoor unit aka blower/fancoil leaking water?
A1. Can be caused by a blocked drainage pipe by jelly or dirt.
      The fancoil internal drain pan is dirty causing water not to discharge properly.

If the drainage pipe or internal dirty, a normal servicing will be sufficient to solve the issue.
They will use a vacuum cleaner to clear the clogged drainage pipe.

A2.  The fancoil coil is choked causing condensation or icing.
If the internal coil is choked, u have to do a chemical cleaning to solve the issue.
For chemical cleaning, the technician has to go to the outdoor unit aka compressor to some people to recover the gas in the system 1st, followed by dismantling the whole blower unit down.
They will then dismantle the fancoil apart and wash the parts with water & chemical.
After washing, they will fix back everything & do a air purge/vacuum & test run the system again.

A3. The system have gas shortage issue causing icing. 
Need to check the gas level & top up to required pressure.
Topping up of gas is not normal & will be explained further later.


Q.  Why my unit is not cooling the room down?
A1. The unit is dirty.
Need to service it.

A2. The system have gas shortage issue causing insufficient cooling. 
Need to check the gas level & top up to required pressure.
Topping up of gas is not normal & will be explained further later. 


A3. Outdoor unit might have a faulty part.
The outdoor unit have a few parts which plays an important part in supplying gas to the room.
Expansion valve : controls the amount of gas to each individual fancoil unit.
PCB: Controls the valve & other parts by sending signal to them via feedback from the indoor fancoil pcb.
Fan motor : Blows out the hot air generated by the compressor & coil.

A4. Indoor unit might have a faulty part.
Air sensor : senses the room temperature & sends signals to the outdoor pcb to tell the compressor to cut off/stop working when room temp set on yr remote is achieved.
Thermistor : Senses the gas temp in the copper coil & feedback to the pcb, similar to the sensor.
PCB : Brain/control unit of the indoor unit & communicate with the outdoor unit.

Q.  The indoor unit is noisy.
 A1. Can be caused by a noisy fan motor.
The fan motor spins the rotor to churn out the cool air. 
If the noise level decrease if u set the fan speed to lower, most likely its the fan motor causing the noise.
Need to replace the fan motor.

A2. Can be caused by a choked cooling coil/choked rotor.
U will hear some uneven airflow sound after u on the aircon for 10-15 mins.
As the coil/rotor is choked, air will not pass through smoothly which explains the uneven airflow sound. 
Need to do normal/chemical cleaning.

Q.  The outdoor unit aka compressor is noisy.
A1. Can be caused by a noisy fan motor.
Need to replace the fan motor.

A2. Can be cause by loose parts due to them rusting/corroding over time.
Certain metal parts holding the outdoor unit together might have corroded, causing noise during operation.
Can replace the parts or consider replacing the outdoor unit/whole system is system is deem unserviceable due to old age.

A3. Can be caused by a noisy compressor.
All compressors are covered by a 5 years warranty. However this warranty usually cover parts only & not the labour.
U need to engage the agent to come & replace for a fee.
Price ranges from $350-$500 to replace the compressor.

Q.  Operation light flashing.
A1. Different brands of aircon, when experiencing malfunction will have a blinking operation or timer light.
Need to get a technician to diagnose & narrow down the possible faults.

In my opinion, an aircon system when used daily > 6 hrs will have an average lifespan of 5-8 years.
Anything major repair that needs to be done after 8 years, do consider to have the whole system replaced to avoid further repairs.
When replacing the system, best to replace the piping together if possible to avoid any complications with the new system.


 




 

Control Wiring

Recently there are many cases of aircon wiring broken or faulty after a few years of installation.

This will lead to aircon not being able to function and owners have to replace their wiring from the blower to the compressor.

In some cases, the wiring is already hidden inside false ceiling or built in cabinets.

Imagine the trouble you need to go through just to replace the faulty wiring.

This is mostly caused by poor quality materials used during the initial installation.

Wiring is as important as the grade of copper piping used.

From the indoor units (Fancoil) to the outdoor unit (Compressor)

Min should be 3c40.

This means there are 3 cord of rubber enclosed wire, each with min 40 strands of copper wire inside.

If they use 4c40, means there is an extra cord for next time backup, in case one cord is faulty in future.

If they use 3c70, which means there are 70 strand of wire inside, this is even better but usually you have to top up a bit of $ for this upgrade as the material cost is higher.

The brand of the wire matters a lot.

Do try to avoid brands made in erm.... u all know. PR*.

Local brands like Keystone & Tai Sin are known to be reliable.

I will advise all owners to confirm the brand of the wiring used by your aircon installer before committing to the purchase.

If budget permits, do consider an upgrade to the 4 cord or 70 for long term usage.

NEA Energy Efficency Rating Scheme

As on 1st Sep 2013, some models of air-conditioners are being phased out as they fail to meet the min requirements set by NEA.
They are mostly non inverter single & multi split aircon equipment.
For non inverter, only Daikin multi model Ma56 (connectable up to 4 units) are allowed to be on sale.
Some inverter models failed to meet the min requirement too.
More details @ NEA Website.

Do note on this when considering your aircon purchase.

R22 gas phase out.

Many users are concerned about the availability of R22 gas.
R22 gas will be phased out in stages, by 2020, it will be reduced by 99.5%.
By 2030, there will be no more production of R22 gas.
Info taken from (http://www.epa.gov/ozone/title6/phaseout/hcfc.html)

It is still safe to purchase R22 gas equipment now assuming average lifespan of aircon units are between 5-7 years depending on usage.

However, many brands are no longer producing equipment using R22.
Only inverter multi system that uses R22 is Daikin.
Rest are using R410a. (To my knowledge)

So do not worry for now.
 

Btu Calculation

For most new HDB flats.
4 rooms.
Estimated btu for the bedrooms are 9k btu each.
Living will be 18k btu.

3 rooms
Estimated btu for the bedrooms are 9k btu each.
Living will be 12k/18k.

If you hack the master room and bedroom 2 into one room, i will suggest at least a 12k btu. but 18k will be more comfortable in terms of cooling.

Rough guide for calculation of btu.
Take your square area of the room multiply by a factor of 400-500.
400 for lower requirements/number of people in the area.
500 for higher requirements/number of people in the area.

Say a bedroom square area is 18 square metre.
18 x 450 (middle range) = 8100.
8100 nearest btu is 9k btu.

This formula is taking into account of a ceiling height of 2.5-3 metres.

The same formula can be used for pte apartments.
But for calculation of the living/dining area if the ceiling is of a higher height.
Maybe u can multiply by 600 instead of 500 to factor in the higher ceiling.

A ceiling fan may be useful too for faster distribution of the cold air.

 

2 trips installation

I have noticed many people asking abt 2 trips installation, especially for home owners whose house are undergoing renovations.

For aircon installation, we can break them up into 2 parts.
1. Running of piping, trunking.
2. Installation of equipment.


For 1 trip installation,
1. It will applies to those who are currently staying in the house 
2. Those who are replacing their current aircon unit.

If your house is undergoing renovation and u install your aircon in one trip.
The aircon installer will usually cover up the fancoil with a plastic sheet first.
There are some issues which i realised.
If the installation is done BEFORE the painting, then the wall behind the fancoil unit will not be painted and 5-7 years down the road , when you need to replace a new system, the wall will be of a different colour and you might need to touch up on the painting.

If the installation is done AFTER the painting, your trunking will not be painted. Trunking is usually glossy white in colour.
Unless your painter is willing to make 2 trips to touch up or you pay extra $ to the painter.

For 2 trips installation,
It is good as after the trunking is run, the painter will paint the trunking and the wall.
When the house renovations is almost done up, the installer will make a 2nd trip to install the equipment.
This requires coordination between the installer and your interior designer.
So sometimes house owner uses the aircon installer which the interior designer recommends as coordination works is easier.
Finding an aircon installer direct may be cheaper, however you may need to coordinate and spend some time going on site to discuss with the installer on the pipe routing.
If dealing through the designer, you can discuss the routing along with your other services, like electrical power point, ceiling etc.

Some companies provide 2 trips installation free, some will charge.
Market price will range from $50 - $150 for 2 trips installation.

Comparison between brands

Confused between what brand to choose during your aircon purchase?

I will do some comparison between different brands for inverter outdoor units.
I suggest getting an inverter unit if you use the aircon units daily for > 6-8 hrs.

I will compare the 3 brands outdoor units which i usually will recommend to my friends for aircon purchase.

Daikin inverter sys 3 R22 gas model :: 3MKD75DVM
Cooling Capacity
This unit has around 27k btu.

Noise Level 

Noise level for all inverter models, i feel that its quiet so no issues if the unit is working normally.
The rated db is 46.

Energy Consumption 
Max rated amp is 13.4 amp.
If unit is running @ part load, amp is around 6.5 amp.
Based on $0.2878 per kwh.
It will cost $0.43 per hr to run the outdoor unit @ part load. 

Mitsubishi Electric inverter sys 3 R410a gas model ::MXY-3A28VA
Cooling Capacity
This unit has around 27k btu.

Noise Level 

The rated db is 48.

Energy Consumption 
Amp stated is 8.5.
If unit is running @ part load, amp is around 6 amp.
Based on $0.2878 per kwh.
It will cost $0.39 per hr to run the outdoor unit @ part load. 

Panasonic inverter sys 3 R410a gas model ::CU-3S27MKZ
Cooling Capacity
This unit has around 27k btu.

Noise Level 
Unknown.
Energy Consumption 
Amp stated is 9.4amp.
If unit is running @ part load, amp is around 6 amp.
Based on $0.2878 per kwh.
It will cost $0.43 per hr to run the outdoor unit @ part load.

All information are taken from catalogue/information given by airconditioning technicians.  
Energy consumption is a rough estimate.