Air Conditioning Units not cold

[Nereus]

Anyone recommend a reputable Air Con service tech?

From this forum: http://hhbd.net/hua-hin-property-land.htm

Nut Air Service Ltd
Air Conditioning, Electrical, Plumbing, Reticulation Systems
189 Moo 2 Wangpong Mob: 089 259 7692

He speaks excellent English, so if he stuffs it up you can tell him! And then tell him that following that, you will report him to me.

[advocate]

What you are calling the "discharge" is the condensation water drain, and yes, they do get blocked up.
The "discharge" is the high pressure piping connected to the load side of the compressor.[/quote]

Thanks, I don't mind admitting I don't know a lot about AC. Actually it's kinda obvious.

I do recall though that our units weren't cooling as well when the drains were clogged. Did not need any freon, just flushed out the drains.

[chaspul]

You will know if a condensate drain is blocked as it will "rain" inside your house.
Happened regular in Saudi due to the dust storms.
Company introduced a monthly servicing policy as due to poor house design (new build) the unit in the living room had too shallow a run off and ended in a soakaway drain. Sometimes had to call maintenance before the monthly service as AC running all the time due to 50-55C temperatures.

Its not mould its "mud", dust and skin particles, if blocked the only way to shift it is to put air pressure into the pipe. AC mechs use their freon tank to do this, I have adapted an American walk around air resevoir, the type that can be used to pump up car tyres.

I clean the filters regular here but they seem very clean, do not use much AC anyway. A sevicing policy should be determined on your usage and air conditions. Filters are easy to inspect and clean and an indication can be determined by dust build up on counter tops, which will be worse if you are living near a new build development, or pollen in the air.

However, been noticing over the past few months that the bed room unit, LG 3 years old, had bugun rattling on start up and run down.

As stated don't use it a lot, but maybe fan bearings are wearing out?
Decide to investigate, stripping all of the air directional louvers out to access the fan.
What I found amazed me, the fan a full length rolling type was almost completely blocked and in places the "mud" had increased the diameter by about 1.5 to 2 mm.
Not realy suprising I though as its plastic and the rotation will create static, attracting dust.

Took more than an hour to clean using a 1" paint bush and then a second pass along the whole length washing it with plain water, do not use detergent as this helps dust to stick, all in all a messy job.

Switched power on again, same rattle, turned out that the plastic moulding that runs the length of the unit and forms the condesate trough had warped slightly. Easily fixed with a couple of wooden wedges.

Now I have a AC unit that dosn't rattle and the room gets cold amazingly quickly.

Chas

[Bernard]

Chaspul, thank you for that. One of my units "rained" in the apartment which is what first alerted me to them maybe needing a service.

[chaspul]

Seems to be mysteries about AC units and refrigeration. Looked both up on Google but fairly complicated descriptions for the layman. Will try to explainin in simple terms, so as to assist in diagnosing what may be wrong, apologies if you know already.

Both your fridge and AC work on the same basic principle, a liquid is heated, turns into gas, the hot gas is cooled and returns to a liquid to start the cycle again.
My first fridge used an electric element to heat the liquid (ammonia) and gas heated fridges were also available.

Most will have a split level AC, so called because this process is split between inside and out. Window units have all the same components in one box and can be more noisy.

Your outside unit contains a reservoir of liquid refrigerant, also a compressor (more efficient than heating element)which through compression heats the liquid turning it to gas.

The hot gas then runs through cooling coils on the inside unit condensing the gas back into a liquid, thus creating a cold surface. This is helped by the fins surrounding the coils.

The liquid returns to the outside unit which also has a fan to extract the heat to atmosphere. The cycle starts again.

In a fridge the cooling fins or condensing plate are in an enclosed box. An AC unit uses a fan to draw air past the cooling fins through the filter and project it into the room.

The cooling process produces condensation (water from the air) to form on the outside of the fins which drips into a trough and through gravity drains to the outside. This does not affect the working or temperature of the AC even if the drain is blocked. It can be likened to the puddle of water that forms on your beer mat.
In a fridge this condensate returns via a pipe to sit on top of the hot compressor where it evaporates.

To test if AC is in need of major service;
1. Check to see if the compressor outside is working, you can hear it.
2. Remove inside unit filters and clean.
3. Are the fins getting cold? If yes you have a refrigerant cycle. Very unusual to need refrigerant liquid.
4. Are the fins clean? if no this will not allow efficient condensing of the liquid.
5. Is the fan clean? See my previous post. The fan is meant to draw room air through the filter. past the cooling fins and project it into the room. Due to design tolerances the fan also takes some unfiltered air from the room and can become clogged.
6. At The same time check condesate drain for blockage by introducing water to the trough. This can be awkward, I use a 5ml syringe (supplied with HP ink refills) filled with water several times. If blocked you will need air pressure to clear.

Not all of these problems will be picked up if the AC mech only "Cleans the filters and clears the condensate drain" and the freon rarely requires topping up unless you have a leak.

Hope this helps to sort the mysteries of AC, I know it is generalised but some may find it helpful.

Chas

[Dannie Boy]

Seems to be mysteries about AC units and refrigeration. Looked both up on Google but fairly complicated descriptions for the layman. Will try to explainin in simple terms, so as to assist in diagnosing what may be wrong, apologies if you know already.

Both your fridge and AC work on the same basic principle, a liquid is heated, turns into gas, the hot gas is cooled and returns to a liquid to start the cycle again.
My first fridge used an electric element to heat the liquid (ammonia) and gas heated fridges were also available.

Most will have a split level AC, so called because this process is split between inside and out. Window units have all the same components in one box and can be more noisy.

Your outside unit contains a reservoir of liquid refrigerant, also a compressor (more efficient than heating element)which through compression heats the liquid turning it to gas.

The hot gas then runs through cooling coils on the inside unit condensing the gas back into a liquid, thus creating a cold surface. This is helped by the fins surrounding the coils.

The liquid returns to the outside unit which also has a fan to extract the heat to atmosphere. The cycle starts again.

In a fridge the cooling fins or condensing plate are in an enclosed box. An AC unit uses a fan to draw air past the cooling fins through the filter and project it into the room.

The cooling process produces condensation (water from the air) to form on the outside of the fins which drips into a trough and through gravity drains to the outside. This does not affect the working or temperature of the AC even if the drain is blocked. It can be likened to the puddle of water that forms on your beer mat.
In a fridge this condensate returns via a pipe to sit on top of the hot compressor where it evaporates.

To test if AC is in need of major service;
1. Check to see if the compressor outside is working, you can hear it.
2. Remove inside unit filters and clean.
3. Are the fins getting cold? If yes you have a refrigerant cycle. Very unusual to need refrigerant liquid.
4. Are the fins clean? if no this will not allow efficient condensing of the liquid.
5. Is the fan clean? See my previous post. The fan is meant to draw room air through the filter. past the cooling fins and project it into the room. Due to design tolerances the fan also takes some unfiltered air from the room and can become clogged.
6. At The same time check condesate drain for blockage by introducing water to the trough. This can be awkward, I use a 5ml syringe (supplied with HP ink refills) filled with water several times. If blocked you will need air pressure to clear.

Not all of these problems will be picked up if the AC mech only "Cleans the filters and clears the condensate drain" and the freon rarely requires topping up unless you have a leak.

Hope this helps to sort the mysteries of AC, I know it is generalised but some may find it helpful.

Chas

As a layman, I found this very helpful and reasonably straight forward, such that I will give it a go myself when the first service is due!!

[Nereus]

100% marks for effort chaspul, but you miss a couple of very important points. I would also point out here that the old adage of "a little bit of knowledge is dangerous", is very relevant!

There are high pressures contained in any air con / refrigeration system, and although it may not be a problem just cleaning parts of it, if you are tempted to try and do any more without proper training, you run a very real risk of injury, or worse. The equipment also operates on mains voltage and will have no compunction about electrocuting you if you do not know what you are doing.

There is nothing wrong with anyone having an interest in how stuff works, but do yourself, and your family, a favour and leave fixing stuff like this to people who are qualified and experienced.

[Big Boy]

As stated earlier, it cost us just 350 Baht to have 2 units serviced. At those prices (less than one Baht per day), it just isn't worth the effort.

[chaspul]

My Point BB is are they actually servicing your units or just ripping you off? Cleaning the filters and condensate drain may not solve everyones problems. 350 Baht for two units, how long and how often are they with you and how deep do they go? Is this just another contract scam?

Nereus Thanks for the 100% YES I did forget to add the dreaded H & S Warnings.
H&S comes as second nature to me, sometimes one forgets to pass it on.

I do have a lot of Knowledge about HVAC and only passed on the simple things people can do to check or inspect theirs. Read the post more carefully.

Health and Safety Warning

My units have a remote isolation switch, if yours are hard wired (not agood thing) do not attempt cleaning them yourself without throwing a breaker, if you have one.

Also do not attempt to break into the refrigerant system. In none of my previous posts have I ever advocated this and it would need a mech with his gas bottles to do this.

All of my points are still valid and despite Nereus critique are simple and easy to carry out.

Health and Safety Warning

DO NOT FALL OFF THE LADDER.

Chas

[Big Boy]

My Point BB is are they actually servicing your units or just ripping you off? Cleaning the filters and condensate drain may not solve everyones problems. 350 Baht for two units, how long and how often are they with you and how deep do they go? Is this just another contract scam?

I don't think I was ripped off. The second unit was cheaper because they told us that it did not need a full service. The 2 guys took about an hour, and stripped the units down, and did what was required. The unit that was giving problems is like new again.

Surely, if it was a scam, they would have charged the full 250 Baht for each unit.

We don't have any contract with them, they just recommend we call them back in about another 6 months - no pressure.

[Nereus]

I am not going to be drawn into a mud sling contest with you, or any body else, but some of your posting is just plain wrong, regardless of your comment that it is just a general outline. If you are going to give advice it is better to quote facts, not something that you have gleaned from the Internet.

Your outside unit contains a reservoir of liquid refrigerant, also a compressor (more efficient than heating element)which through compression heats the liquid turning it to gas.

It is not possible to compress a liquid, simple. The compressor draws gas, not liquid, and compresses it to a higher pressure, which causes it to heat. Try pumping up a bicycle tyre (or is that tire?), with a hand pump and note how hot it gets.

The hot gas then runs through cooling coils on the inside unit condensing the gas back into a liquid, thus creating a cold surface. This is helped by the fins surrounding the coils.

No again. The "hot" gas is released into the evaporator, via a device called an expansion valve, which causes the gas to expand, lose pressure, and return to the liquid state. The expansion valve is probably the most important part of a system, and various types, including capillary tubes, are used. The fins surrounding the coils are there to provide a larger cold area for the circulating air to pass over, not "help" the gas expand.

The liquid returns to the outside unit which also has a fan to extract the heat to atmosphere. The cycle starts again.

The liquid is condensed, hence the name condensing unit, back into a gas by passing through the fan cooled tubular coils of the condenser. Most small house sized condensing units do not have a "reservoir", or more correctly, a "liquid receiver", the capacity of the condenser itself being sufficient.

Also do not attempt to break into the refrigerant system. In none of my previous posts have I ever advocated this and it would need a mech with his gas bottles to do this.

You do not have to "break into" the system to risk being exposed to high pressure. Just ask the "knowledgeable" DIY person that is now blind because he ruptured a soft aluminium tube with a sharp object while trying to "clean" it.

I do have a lot of Knowledge about HVAC .....................

Is that right? from your description obviously not.

Read the post more carefully.

I do not need to be told by you, or anybody else, how to read, I have been doing it for the last 65 years, and yes, a lot of it in the Middle East!

Like I wrote at the start, 100% for effort, but sadly let down by your assumed actual knowledge.

[chaspul]

Nereus

For not wanting to sling mud you always seem to do pretty well.

You obviosly have been reading the internet for your facts, where as I had formal Instruction and much practical experience both on airliners, cars and domestic units.

Not doubting your reading ability just your understanding of my reply to the OP which was stated as only a brief outline. Contrary to your reply I am not completely wrong, a little knowledge may help people understand how basic things work.

As stated I only went on the Internet to find out what information is available and found much of the information, although correct would be confusing for someone who is just asking "Why is my AC unit not cold" which is the subject of this thread.

All your informed information is correct but irrelevant to the layman, I only consider that a brief principle in how it works relevant, after all If something is drasticly wrong I would call in a AC mech, he has the correct tools.

I have only suggested attacking the units with a 1" paintbrush.

My LG units (as most ACs) all contain exposed copper pipes which will not be harmed by said paintbrush only a complete moron "handy man" would try to clean with a sharp object, who was he?

In fact I can only remember seeing Aluminium used in an exposed pressure system once, it was on the bursting disc in a VC10 aircraft fridge pack. Where the rest of the pipeing was stainless steel, it runs at much higher pressure than a domestic unit.

My advice still stands.

Not trying to do a Thai AC mech out of a lively hood just trying to be helpful. Is cleaning classed as work?

Chas

[Big Boy]

Is cleaning classed as work?

I often use that one to (unsuccessfully) try to get out of general housework

[chopsticks]

For sure you can clean and maintain yourself. As previously mentioned tesco lotus sell an aerosol cleaner to do a thorough job.

[bonnielass]

BB

Can you send me PM with the telephone number and name of who you got to clean your A/Cs.
Think mine need a bit of an overhaul.

thx

BL