R-134a Recharge Pressure


#1

I’m planning to add a little R-134A to my '95 Mercury Cougar tomorrow. The A/C was last worked on during the summer of '99, and it isn’t performing very well anymroe.

What are the proper high side and low side pressure ranges for this vehicle? Is it worth it to get a gauge set that has the high side, or just get one with low side only?


#2

A charging hose for the low side only can be used successfully, especially if the system is still partially cooling and not completely empty.
I prefer a full gauge setup because it can tell someone much more about what is going on inside the system.

Pressures are impossible to state since that varies by ambient temps, humidity, whether the car is in the sun or not, engine RPMs, state of charge, etc. Roughly speaking, you should be seeing around 35 PSI on the low side and 225-275 on the high if you use a full gauge set.

A few warnings also. You should wear a pair of safety goggles always and if you use a full gauge set you must heed this advice. You NEVER, EVER open the high side valve on the gauge set when the can of refrigerant has been tapped and the tapping valve has been opened. This can cause the can to explode. Refrigerant will freeze fingertips in a few seconds and cause blindness instantly if it hits the eyeballs.
ALWAYS make sure the high side valve is closed before tapping and opening a can.

I’ve seen a couple of cans go off (not by me and no one was hurt), and speaking after the fact, it was somewhat comical to see someone disappear in a cloud of steam.

I would also advise that you simply not add refrigerant only. With refrigerant loss there will be some compressor oil loss too so use the can of refrigerant that has a quantity of oil in it already.
Hope that helps you out some.


#3

The tips OK mentioned sound very good. I’d also note that for simplicity’s sake, since the system is still working somewhat, you can probably get away with the following: Get yourself a low-side charging hose. Connect can to hose and tap the can. Turn the system on full-blast. Open the valve on the can to purge any air from the hose and connect the hose to the system while the valve is still cracked—this will minimize any air getting in. Put the can in a small pan of warm water -not boiling- (always keeping it upright, as liquid refrigerant can ‘hydrolock’ and damage your compressor)

Under the hood there should be a sticker detailing the total amount of refrigerant the system should be charged with. If it’s already cooling somewhat, you probably don’t want to add more than a third of the amount listed here. Always wear gloves and goggles when working with refrigerant. Also keep in mind that since you will be doing this with the engine running, that there’s rotating parts, belts, etc. that your charging hose, clothing, etc. can get caught in.


#4

How much oil do you add on a full system evacuate and recharge? And do you add it before you add the refrigerant, or after?


#5

It is always best to have high and low side gauges. When servicing, high side pressure can go ballistic, more so for R134 than the old R12. A very powerfull fan blowing through the grill is beneficial. And an understanding and respect for the potential for damage is very beneficial.


#6

Had a missunderstanding today when using the words “recovery” and “evacuate” With a recovery you will loose some oil(my experience 1-1.5oz) An evacuate will not remove any oil.How did you or how will you recover the refridgerant charge?Your system must be empty to evacuate.


#7

cheap ghds
Cheap ghd straighteners
Pure Black GHD
Pure White GHD
Benefit ghd
ghd Mini Styler
Kiss GHD
Pink GHD
Pure Black GHD
Rare GHD
cheap ghds
Cheap ghd straighteners
Ghd
ghd straighteners
Benefit ghd
ghd Mini Styler
Pink GHD
Pure Black GHD
Pure White GHD
Rare GHD
cheap ghds
Cheap ghd straighteners
cheap ghds
Cheap ghd straighteners
Benefit ghd
ghd Mini Styler
Rare GHD
cheap ghds
ghd
Cheap ghd straighteners
Benefit ghd
ghd Mini Styler
Pink GHD
Pure Black GHD
Pure White GHD
ghd
cheap ghds
Cheap ghd straighteners
ghd Mini Styler
Kiss GHD
Pure Black GHD
cheap ghds
ghd straighteners
Cheap ghd straighteners
Benefit ghd
ghd Mini Styler
Kiss GHD
Pink GHD
cheap ghds
ghd straighteners
Cheap ghd straighteners
Benefit ghd
ghd IV Salon Styler
Pure Black GHD
cheap ghds
Cheap ghd straighteners
Benefit ghd
ghd IV Salon Styler
Kiss GHD
Pure Black GHD