You’ve spent a fortune renovating your house and after many years when the air conditioners are old. You’ll like to simply replace the air conditioners while keeping all the pipes. But, the pipes are leaking, and you wondered what had gone wrong?

Pipe leakage is often caused by acid build up within the gas system or damage to the flare joints. If it is damage to the flare joints, it is still not so bad. Technicians can simply cut away the damage joint and weld/braze a new copper pipe to replace the damaged section. But if it is due to corrosion caused by acid build up, replacement of the pipes is inevitable.     

This is probably the history why your pipes are leaking: Full dismantling of fan coil for chemical cleaning without ensuring joints are not damaged resulting in future gas leak.

The compressor uses a large part of the returning suction gas to cool the compressor down. But when a system runs out of gas, there’s little cold returning gas to cool the compressor down. This will overheat the compressor.

When a compressor overheats, it will trigger an overload relay to shut down the compressor. The compressor will only spring back into action after it has cooled down, it can take 1-2 hours for that to happen. So you get a technician to come in and he top up the gas for you, not knowing where it was leaking from. And this continued for a long time until your compressor finally fails. But before the compressor fails, a series of events could have unfolded:

Removing of overload relay in order to force run a compressor

When a compressor overheats, it will trigger an overload relay to shut down the compressor. The end result is that the air conditioner no longer produces cold air. If at this moment, a technician bypass this overload relay in order to force- run the compressor, it will cause the compressor to overheat above 150’C.

When the temperature of the compressor rise above 150’C, the compressor oil will fully disintegrate. Meaning, this will cause enormous wear and tear to the compressor, and causing the dryer filters to be choked. The compressor becomes very hot and inefficient and starts to damage the electrical components like starters and magnetic contactors, even condenser PCB boards.

If the temperature of the compressor further exceeds 250’C, the R22 gas will break down and produce acid in the
presence of water moisture (when you fully dismantle the fan blower and wash with large amount of water). The acid will slowly corrode the copper pipes, resulting in leakage at places least likely to occur; at the connecting pipes, which is possibly tucked away from sight; above the false ceiling, inside walls or behind cabinets. This will be a home owner’s worst nightmare.

Now that you know….

During new system installation, insist and be around to witness proper vacuuming of the copper pipes to remove excess air and water moisture. When all is done properly, the technician will release the valve in the condenser to fill the system with the pre-packed liquefied gas. This is a “critically charge”, a calculated amount of gas, do not over-charge it. Then make sure that all nuts are properly tightened.

Do not top up the gas unnecessarily! After few years of usage, the fan coil will be dirty and thus not capable of fully evaporating the liquefied gas, pressure will be low. But this does not mean there is a gas leak. Conduct a proper chemical cleaning will restore the aircon to factory condition once again.

Do bear in mind that gas needs no recharging. Many cheap refrigerant in the market may not be clean nor moisture free. Contaminating your otherwise perfectly clean system may shave off a few useful years off your aircon. This explains why some aircon that were not serviced regularly outlast regularly serviced aircon (with gas charging).