Converting to 134a

[Tim]

I noticed a thread on the Festiva Mailing List about a changeover from r-12 to r-134a. I think it was Burgess who mentioned that all he did was flush his system and replace the receiver/drier.

Is this practical? A good idea? Since my A/C is f'd up right now would it be worth getting another receiver/drier along with the compressor and trying to make it work?

Since 134a isn't quite as efficient as r-12 would a condenser fan be a good idea too?

Also, wouldn't the difference in pressures affect the system? As well as trace amounts of R-12 oil?


Regards,

Tim

[FB71]

Timmy!

the pressure differences aren't that great, so that shouldn't be a problem. My personal experiences with r-12 to r-134a; add a condenser fan AND change to an r-134a condenser for the most effective cooling, change the dryer, flush the lines and evap w/ denatured alcohol and blow dry, drain all oil out of the compressor, refill with Ester oil (not PAG or mineral), and recharge with r-134a to 80% of the specified r-12 weight. Also, the hoses originally designed for r-12 are not compatible with r-134a. R-134a molecules are smaller than r-12's, and r-134a will weep through rubber lines intended for r-12. This is evidenced by the hoses feeling oily on the outside after a few months. Once this starts, they tend to fail rather quickly. R-134a hoses have a nylon lining to prevent this.

By the way, incomplete evacuation of moisture from the system can cause compressors to fail prematurely. Be sure to evac three times for 1 hour each with a 45 min rest between. That's the best way to ensure removal of moisture.

[Tim]

I see.

I have most of the stuff for 134a that I got from another Festiva (ie compressor, condenser, R/D).

So if I convert it over can I still keep the TXV and the stuff inside the heater core as it is?

I'll need new lines as the old ones got hacked up during removal...


Regards,

Tim

[FB71]

sounds about right....

[Tim]

The 134a condenser is a tad thicker and maybe about 2" longer than that Festiva condenser; since the condensers are so close would it really make a difference keeping the old one?

[Tim]

Went and compared the 134a parts to r12.

The Condensers are exactly the same size; the Festiva one is better built and has fan mounting brackets. The 134a compressor has its own mounting bracket and some weird idler pulley setup.

Don't know about the receiver/drier. Again, it's the same size as the Festiva one but has the pressure switch on it instead of on the high pressure line. I put one of the valve caps over one line to the condenser, and left the other still attached. However, the other end of the condenser has been unplugged and exposed to the air for the last few months. Would this destroy the receiver/drier?

[Eccentric]

I would try using an R-12 substitute like Red Tek. Before going though the hassle of converting. There are a few different substitutes out there you might want to look at before you buy one.

[CryptokiD]

one substitute i am quite fond of, is propane. it can replace r12 perfectly, with no conversion or oil changes nessassary. just gas it and go.

been using propane in everything i own. its 1000 times cheaper than real r12, and atleast 100 times cheaper than r134a.

[FB71]

and 10,000 times more flammable and deadly......

there's a reason propane is banned in mobile refrig units.....

don't let anyone important (ie, EPA) know you're doing that, there's a big fine and jail time involved....

[oxbrain]

so that's how those cars in movies explode when they hit a speed bump too hard.

seriously, propane is about the worst thing you can use for refrigerant. It's extremely flammable and burns at high heat. Get into an accident and BOOM. If it leaks in the engine bay, big fire. Leak into the passenger area and you are smoking or the dome light sparks and big fire and you burn. Leak into the air and someone is standing next to your car smoking, whoosh.

The money you save isn't worth it. And if you get caught it's a huge fine, minimum 5 figures. If anyone is injured then it means jail time and reparations and a fine and you probably lose your license.

[Tim]

IIRC they used propane for refrigerators "back in the day"?

My mechanic told me there's some new refrigerant that just came out and he received a sample of it. Anyone know about this?


Regards,

Tim

[FB71]

not familiar with it, but new stuff is always fun to experiment with...

as for old fridges.... stationary..... not mobile..... no internal combustion engine right next to it....... also, that was VERY early, and was only commercial refrig. Household refrig was always a cfc refrigerant as manufactured. And don't forget ammonia, that was the first refrigerant experimented with back in the 1800's.....

[Tim]

I've heard of the ammonia A/C. Many old buildings still have those systems.

I remember reading about a fridge you hooked up to the gas line; not sure how it worked exactly.


Regards,

Tim

[FB71]

it used a pilot lite to "boil" propane in the system causing high pressure to build. That pressure would force propane past an orifice, where it would expand and collect heat. It then went through a condenser, and finally fed the pilot lite. Total loss refrigerant....... (it didn't recycle through the system)

[Tim]

That setup sounds extremely dangerous...


Regards,

Tim