Losing Charge When Uninstalling Split Air Conditioner

When moving residences I had an experienced air conditioner installer remove my Whirlpool split (ductless) air conditioner. It sat unused for about a month and then a different person installed it in the new house. This person told me that the unit needed refrigerant because the original refrigerant was lost when the unit was removed from the old residence.

I'm trying to determine whether he's full of it and just wants to charge me more $$ for additional refrigerant or whether it would have been easy (and therefore likely) for the original guy to screw up and let the refrigerant escape.

Any advice on how easy/difficult it would be for the "uninstaller" to make a mistake which caused all of the refrigerant to escape the system?

As an aside, I live in Morocco and while both of these individuals are experienced with installing and uninstalling these units, they are not "certified" etc.

 

It depends upon what the "uninstaller" did. If he simply closed the refrigerant outlet valve and then ran the unit until it stopped on high head pressure he may have left a significant amount of refrigerant in the evaporator and suction piping that was lost when he uncoupled the piping. If he used a "recovery machine" then most of the refrigerant would have been removed to the recovery tank of the recovery machine. If the original installation had used a longer line set (the copper tubing connecting both units) then additional refrigerant would have been added at the initial installation.

At any rate, it is highly unlikely that the entire original refrigerant charge was contained in the condensing unit and therefore re-installation would necessarily require additional refrigerant, maybe a small amount, maybe a complete new charge.

 

Thanks Furd.

One reason I thought perhaps the "installer" was dishonest was that he charged me 300 dirham (about $35) for a refrigerant charge at the time he installed it but when I went to use it a couple of weeks later, it didn't blow cold air. When he came to look at it, he said there "wasn't enough" refrigerant but that for another 200 dirham, he would add more refrigerant and then everything would be fine.

Does that make any sense?

 

You can't just put a certain amount it like you can an empty system on a car. It has to take in the length of the line set, how much may have been left in the system, temperatures, etc. A true tech would know all this and hook his gauge set up and fill according to operating parameters.

$35? Wow...that could easily run $300 here in the States, depending on the type of refrigerant..

 

As Gunguy mentions you can't just connect a tank of refrigerant and guess at how long to let it flow into the system. Well, you CAN with certain systems if you are also measuring the various temperatures and pressures but this would be uncommon on any residential A/C system installed in about the last thirty years or so. Most residential A/C systems are critical as to their refrigerant charge. Depending upon the type of refrigerant and the actual amount added the price you paid could be extremely low to completely reasonable.

There also could be leaks in the new installation allowing the refrigerant to leak out. A competent installer would first pressurize a new installation with dry nitrogen and monitor the pressure drop, which should be zero over the course of several hours making allowances for ambient temperature changes. Next he/she would dump the nitrogen and use a vacuum pump to draw the system down to near a perfect vacuum and again allow a period of time to see if the vacuum decreased significantly which would either signify a leak or an excess of moisture in the system.

After the installer is assured there are no leaks they would then introduce the measured refrigerant charge, an amount calculated according to the total internal volume of the system. At this point checking the various temperatures, including ambient temperature and dew point temperatures along with pressure in different parts of the system, the refrigerant charge would be "adjusted" for optimal performance by adding or removing minute amounts. All of this requires several pieces of specialized equipment and it cannot be done without the specialized equipment along with training on how to use the equipment.

 

Thank you so much for the information. I'm sure the installer was all of those things. He came with a screwdriver and his 10 year old son and that was about it