Air Conditioner

[HLC44]

I had the air conditioner repaired a year and a half ago and they replaced the "old" gas (can't remember what it was) with R134A freon. Now it's not working and my question is this: is it just time that it get more freon? It seemed to be working well a couple of weeks ago. I live in Southern California so it's not odd that I'm need the air conditioner in February!

[atobe]

you might have a leak.. did you do a retrofit?? or did they just thew in r134a ?? you have to do a retrofit when going from r12 to r134a... u don't need it now but in july you'll be screaming for it heheeh

[timebuilder]

Go back over your receipt and find out exactly what was done.

In my experience, nothing is better in an R12 system than R12.

If you do change a system, there are several considerations. One is low-permeability hoses. Your original hoses will let R134A escape relatively easily.

Another is a new receiver-dryer with the dessicant required for use with R134A. Your orgianal receiver-dryer contains a dessicant that is not designed to work with either 134A or its oil.

A third consideration is the correct amount of refrigerant, about 80% of the R12 amount. Too much refrigerant in a retrofit will hamper cooling.

A fourth consideration is sufficient airflow over the condenser coils. Using a condenser sized for R12 to condense R134A usually takes more airflow to make up for the undersize.

Since you can buy 134A, you might want to add some refrigerant for a short term solution, but IMHO, all of these considerations must be addressed to make this a good job.

[Doctor J]

Charging a/c with pure R134a usually put high stress on the system because in order to cool properly, the low side pressure is 2 times higher compared to R12. The better alternative is to use Freeze 12( 134a and 142 blend) and to change o-ring seals to these made of green colored rubber.

[timebuilder]

Some alternative refrigerant blends contain hydrocarbons. I would not recommend them.

A retrofit from R12 is a compromise, at best. New R134A systems have the hoses, desiccant, seals, pressure switches and properly sized evaporators and condensers to make the best use of 134A's different vapor pressure.

As a "transitional" refrigerant, R134A is intended to bridge a gap between the nearly perfect mobile refrigerant R12 and whatever can be created that is as good as R12 but which is not perceived as detrimental to the environment.

Although the laws are already passed regarding the demise of R12 and the "facts" of its environmental action are being taught as a requirement for licensing, there is some discussion regarding the veracity of the arguments about R12 and the ozone layer. For example, no one seems bothered by chlorine atoms evaporating from the world's swimming pools and having a similar impact on the environment. If it is the chlorine in chlorofluorocarbons that is the problem, then we have a lot of pools to drain. But, I digress.

The best retrofit includes draining or flushing of old refrigerant oils, replacement of seals, hoses, and dryers (accumulators in some cars instead of dryers) and the addition of electric fans on cars and trucks with mechanically driven fans. A best case scenario would also include replacement of pressure switches with units calibrated for use with the pressures associates with R134A, which are higher than those of R12.

Many simple kits are sold to convert to R134A, and they should only be purchased BY the "simple." Can you get cool air from using a drop-in kit? Sure. How long it will function well, and how cold it can get are the two major issues. A hose, some oil, and a can or two of refrigerant will not be a good as a properly done conversion, called a "retrofit," and nothing in an R12 designed system will ever be as good as a full charge of R12.