Installing a Split
Air Conditioning System

    In Spain and other parts of Europe the summer of 2003 was the hottest in decades and many historical temperature records were broken. I live in a last floor apartment and it was unbearably hot so in the spring of 2004 I decided to look into the possibility of installing air conditioning in my apartment. They do not sell compact "window units" in Spain because they are not suitable for Spanish windows so a split system was the only choice. The problem is that they are expensive to begin with and the installation is also expensive. Normally, with installation included, you are looking at something like 700 to 900 euros. This was beyond my budget but in the spring I saw a system on sale for 199 euros and I thought I could install it myself.

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    I did it but it turned out to be quite a chore.

position diagram
position photo This photo was taken with my camera on the end of a broomstick and hanging over the side of the building.

    My terrace faces west and it would be an easy thing to hang the exterior unit on the wall of the terrace but it would be under the sun all afternoon, during the hours of most heat, which would make it less efficient and also, I did not want to have it there for esthetic reasons. It would be unlikely that the system would be running while somebody was sitting outside but the noise and heat would make it uncomfortable. I decided I wanted the exterior unit on the wall facing north (as shown in the above diagram) where it would be in the shade and out of the way. The problem was how to hang the unit there, 7 floors up from the street.
Standard brackets for AC units.

position diagram

My design for a support that projects into the wall.

Bottom of unit showing anchoring base.
Underside of exterior unit showing the supports with holes for anchoring bolts.
    Normally these units are placed on two brackets screwed into the wall like you can see in the picture on the left. From the terrace I could reach over the side and place one bracket but there was no way I could reach to place the far bracket. And, even if I could, once I had placed the unit on the brackets, how could I possibly reach around it to tighten the nuts and bolts on the far side?
    After much thinking I came up with an idea: I would build a frame which would not be screwed to the wall but would have two bars go directly into the wall so that I could make the holes from the inside and later insert the frame from the outside. Not strictly needed but I added a couple of legs which would rest on the ledge the building has there.
    The problem of bolting down the far side of the unit I resolved by designing a frame where the feet of the unit would slide in sideways under a couple of metal guides in the frame forming a channel. Once the near side was bolted in place the far side was also held down and could not slide out.
    The problem with this idea was that I either had to have the frame custom made, and that would cost quite a bit, negating any savings, or I would have to build it myself, but I did not have the necessary welding equipment. I spent some weeks turning all this in my head and considering the options. I thought maybe I should not have bought the system before I knew how I was going to install it but it was too late now. I was stuck with it and I might as well finish the installation. The problem with having a frame custom made, besides the expense, is that you need to get everything right the first time which is virtually impossible so I would end up making several trips back and forth to the shop and end up dealing with an exasperated shop owner who, once he was paid, would have little interest in making any changes. I thought if I could assemble the frame with nuts and bolts but I thought it would be too complicated and less reliable. So I started looking around for arc welding units. They cost about as much as having the frame made but I reasoned I would be investing in a useful tool. The heavy, transformer-based, units are getting much cheaper because the light-weight switching-electronics type are also coming down in price. I think the old transformer type will soon disappear as they cannot be made competitively and people would prefer the light electronics anyway.
    After much consideration I came across some transformer units on sale. There was a small one which went from 30 to 140 amps and, for very little more, a larger one which went (IIRC) from 50 or 60 to 180 or so. I considered buying the larger one as the price difference was negligible but I am glad I got the smaller one because I needed the lower amps for welding light materials. Arc welding unit
    The unit came with a mask, combination of wire brush & hammer and a few electrodes. It weighs 12 Kg (26 lbs). I had never welded before and I should have practiced on some scrap iron before attempting the real thing but, like a child with a new toy, I could not wait to get started. With clamps I secured the iron pieces to a piece of particle board which would hold them in place. I welded the four corners of the frame and released the clamps only to see the whole thing fall apart. I had welded nothing and the clumps were just slag which would not hold anything. The weather was already quite hot and I was sweating profusely. I should have started the project earlier in the year but now I needed to hurry up.
    I continued my attempts at welding and slowly my clumsy attempts began to succeed although only in the sense that I was depositing shapeless and ugly clumps of iron which were holding the part together. Then I had to do a lot of grinding to get rid of ugly and useless parts. I was taking a lot of time, effort and electrodes to do what a professional would do in minutes but, anyway, I was learning.
    Onr thing I discovered was that in the very bright sun I could see the parts and the electrode before I started welding and this made it so much easier.
Support frame beuing built
The support frame in the early stages of construction. I used some scrap metal from construction debris which explains some green paint on the iron.

Support frame being built

Here you can see how the supports of the AC unit slide under guides. The one on the left has already been covered by a piece which will prevent the unit from sliding further while the one on the right still has to be finished. I also placed a couple of metal stops to hold the unit securely in place.

Making the holes from the inside
I made the holes in the wall for the supports from the inside. It was uncomfortable work which took several days as I did it between some book shelves. Rather than remove the book shelves I removed just one row of books and taped some plastic to the wall to catch the debris. I drilled some pilot holes and then enlarged the hole by using a piece of rectangular iron tube like the one used to build the supporting frame and hitting it with a heavy hammer. Hard work.

Break through
Breaking through the wall. The copper pipe is jury-rigged along the ledge to take water to the terrace for watering the plants.

Hole in the wall for pipes and cables. I wanted the pipes and electrical cables to be recessed in the wall inside so, with hammer and chisel, I had to cut the necessary channel in the hard, solid brick, wall. At the lower left the channel gets deeper and finally goes into a hole which comes out on the other side of the wall. Also hard work which took a couple of days. Through this hole have to pass the two copper pipes for the refrigerant, the exhaust for condensation water, the power cable for the compressor and fan and the signal cables which carry different signals.

Wall channel for recessed pipes and cables.
Wall channel for recessed pipes and cables.
You can see the plastics taped to the wall.

Support frame in place
Although they were not in the initial design, by now I was enjoying the welding so much that I added a couple of legs to rest on the ledge and help support the weight. I also welded some bolts to the inside ends so I could put a nut and washer recessed into the wall which would prevent it from sliding out (not that there was any chance of that happening).

    I finished the welding and then painted the supporting frame with a couple coats of read lead paint and then some white oil based paint. I then installed it in place and it was ready to take the AC exterior unit which weighed 42 Kg (92 lb).
    Like any good sailor would do, I rigged a four part block and tackle hoist from the terrace that forms the roof of the building and another one from a post in my own terrace. A friend was supposed to help me but I couldn't wait for him and I proceeded on my own. The process went quite smoothly as I lifted the unit from the floor onto the ledge and then a bit more while I controlled the lateral movement with the horizontal line to the post. The unit slid into place relatively easily.

AC exterior unit in position.
The exterior unit already in position as seen from the street.
The hole for the pipes is marked by the arrow.

    Now I came upon a problem which I had not anticipated. Nominal sizes for plumbing threaded pipes and fixtures in Spain are in inches but the newer copper pipes for plumbing are sized in metric units. For some unfathomable reason, copper pipes used for air conditioning is sized in fractions of an inch. To connect the indoor and outdoor units I needed about 2.4 m (8') of two different sizes: ¼" for the liquid line and 3/8" for the gas line. I found that it was impossible to buy just a short length of these and I would need to buy an entire coil as they were only sold to professional installers. To make matters worse, the connections are of the flared type which require a special tool to do the flaring and this is a very expensive tool, not worth buying for one time use. As I was thinking about these things I began to think I might need to ask a professional to finish the job but finally I got lucky. I saw a commercial installation being done near where I live and I asked the guy in charge if he could sell me the two lengths of pipes I needed and flare them for me. For 10 euros I got the pipes with flaring and insulation included and some good advice about the final steps of the installation, as you will see. Some days you get lucky.

Flared connection
Copper tube with flared end.

I installed and connected the copper pipes and the electrical cables. pipes and cables in the wall
Insulated pipes and cables embedded in the wall.

Exterior unit connected and ready     When I calculated the length of the pipes I added a bit more for safety. Then the guy who cut them added a bit more for safety and I ended up with tubes which were too long. This was a greater problem that it may seem because I could not cut them without flaring again and they had to arrive at the valves at precisely the right angle. I resolved this problem by bending them in the shape of an S.
    Installation manuals said the flare nuts should be tightened to definite specs with a torque wrench but the installer told me he had not used one in his entire professional life so that gave me some confidence. His specs were "tight but not too tight".
    I also cut to size the electrical cables. After all the connections were done I wrapped the whole bundle with tape and I painted it white.

Exterior unit connected and ready as seen from the street
Exterior unit connected and ready as seen from the street

    Lastly I needed to evacuate the air in the system. Professionals use a vacuum pump and other tools for this operation but I could get around this requirement. I thought I knew how to do it and the advice of the guy who sold me the tubes gave me more confidence. The refrigerant comes pre-charged in the compressor housed in the exterior unit and it is the air in the pipes and the interior unit which need to be removed. This can be done by letting some refrigerant into that part of the system and then letting it out. As it blows out with force it will carry most of the air and humidity out with it. I did this operation twice and then opened the valves normally.
    I then started the system to test it and. . . it worked!

    It took me about six weeks of hard work but finally I could enjoy air conditioning in my apartment. Of course, this only guarantees the summer will be cooler than average and I could have saved myself the trouble.


    En esta página explico cómo instalé yo mismo un sistema de aire acondicionado tipo split, marca Telvisa, modelo AFCR122.

Telvisa AFCR122 specs especificaciones

  Esquema eléctrico de instalación Telvisa AFCR122 esquema schematic

Autor: Alfonso Gonzalez Vespa