R134a for residential use?

[Nandy]

When I was getting my parts today for my residential ac trouble I did some small talk with some of the guys waiting in the counter. One of them told me that he use r134a in his residential unit and had no problems???? I know r22 and r134 are both refrigerant but i was under the impression that a system that is built for r22 is not going to work charged with r134. Is that true? or is it just like when your replace r12 with r134 where the system will work but most of the time it will not be as cool. How about the oil for the compressor? I remember there was a thread here about the use of different refrigerants in residential use but I dont think anyone mentioned r134 to replace r22... anyone wants to elaborate?

 

[MTboatguy]

Re: R134a for residential use?

R134a is not compatible with the r12 units without some modification to the r12 unit the older units need to be completely decharged and dried, and there are some orifices and seals that need to be changed.

 

[Bob_VT]

Re: R134a for residential use?

When older automotive units are converted they are "vacuumed" dry prior to installation. The key is being dry since 134A contains an oil as a lubricant.

 

[RogersJetboat454]

Re: R134a for residential use?

When older automotive units are converted they are "vacuumed" dry prior to installation. The key is being dry since 134A contains an oil as a lubricant.

Automotive units have the remaining R12 recovered, and vacuumed. We then change the receiver drier(gets any latent moisture and oil out) and orifice tube (R134a expands at a different rate than R12). We try to drain as much of the mineral oil out of the system (usually remove the compressor and dump the oil) as R134a is not compatible with mineral oil. R134a does not contain oil. We either use ester oil which is compatible with the little bits of remaining mineral oil left in the system, or PAG oil which isn't compatible with mineral oil but OK to use on new systems. Change the fittings from screw ons (R12) to clip ons (R134a), and charge to the appropriate pressure.

All that being said, I believe R22 is a cousin of R12, so you may have mineral oil in the system which is not compatible with R134a. Secondly as mentioned, you have different pressures and rates of expansion under which these refrigerants work. It's not a 1:1 ratio of poundage when charging the system (if I remember correctly R134a is charged at 20% less than the given poundage for R12). The metering component between the high and low side needs to be changed out to match the expansion of the R134a, in order to get optimal performance. Maybe I'm totally talking outa my butt and the A/C guy who floats around here can tell you otherwise.

 

[Nandy]

Re: R134a for residential use?

Roger, you are right on the money on the automotive conversion. I done one so far and it is working great. Based on that is why I asked. I know these refrigerants have different characteristics but I was not sure if there is anything on the residential units that would help to alleviate the differences. I was really hoping it would be true ad I can fill my system with just $60.00 vs $160.00 that I have to pay for the r22 for someone to fill it. I wonder what it takes to get my unit to work with r134, if possible. If anyone knows or can tell me where to look, here is the as info:
Carrier
S/n 0302e13338
Prod 38ckc036---351--
Model 38ckc036350

This guy was talking as just adding thr r134 without any other mods. It was also a carrier unit.

 

[xxxflhrci]

Re: R134a for residential use?

Not that it's totally on topic, but I have a R12 car. I did not want to convert it over when it got low on refridgerant and did not want to track down and pay for R12. I know a guy that suggested Hot Shot, R414b. I put it in a couple of years ago. So far, it has worked great.

http://www.icorinternational.com/hotshot.html

 

[dolluper]

Re: R134a for residential use?

Duracool + Red Tek have household kits R22a.....mostly the fittings are important....some have to be changed you I think ..not positive are ok

 

[hrdwrkingacguy]

Re: R134a for residential use?

When older automotive units are converted they are "vacuumed" dry prior to installation. The key is being dry since 134A contains an oil as a lubricant.

Any system is evacuated because air isn't condensable, and air displaces volume in a condensing coil and lowers capacity and the condensers ability to make liquid...Since air is largely water it also trashes internal parts of systems and helps create acids...Liquid driers use an adsorbent to chemically bond water to the drier media and are installed any time a system is opened...

As far as converting to 134a it has less cooling capacity per pound then r-12 or r-22...So a 5 ton r-22 machine with a compressor replacement and complete oil clean out and metering device change would be something like a 3 3/4 ton machine...You can make it work but it wouldn't be the same...A lot goes into pressure drops in metering devices and pumping capacity of compressors as well as heat transfer in coils to determine system balance...Unless someone is an engineer I recommend keeping the system as intended in HVAC units...

 

[Howard Sterndrive]

Re: R134a for residential use?

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