1. Home
  2. Jeep and Willys (new and old)
  3. Re: Charging my Air Conditioner

Re: Charging my Air Conditioner

Hi Jeff, If you have over filled it in the past, as I have and wasted some through the pop off valve, then you may have also have ruined the low pressure switch that sits on the dyer that is bypassed on the cycles you describe. If so it simply unscrews without losing any pressure. A good rule of thumb would be 35 psi on low and not over 275 psi on high side:

formatting link
God Bless America, Bill O|||||||Omailto: snipped-for-privacy@aol.com
formatting link

The AC compressor clutch cycles on for about 2 seconds then off for about 3 > seconds then repeats. It never blows cold. It worked fine a few days ago, so > this is a sudden onset of symptoms. > > I have R134a. I also have a guage that plugs onto the Low Pressure Port. The > sad thing is that I've not used it for a few years and I forgot how. > > I have to connect either the guage or the fitting that connects to the can > of stuff, but I can not connect both at the same time. I think I have to > take a pressure reading to make sure it is low. My guage has GRN, BLU, YEL, > and RED sections. Green is 0 to 25psi, blue is 25 to 45, yellow is 45 to 46, > and red is anything above 65, the guage limit is 200. > > I need to re-understand the directions. > > I _think_ I want the needle to be in the blue area or yellow area, but by no > means in the red or green areas. I have not checked yet, but I suspect it > currently is in the green area. Once I ensure that the pressure is indeed > low, then I can add a can of R134. One can should bring the pressure to > 45ish psi. > > I _think_ what is happening now is that my pressure is right on the line, > and when the compressor kicks in, the result is pressure drop below the > threshold of the Low Pressure Switch, so the compressor kicks out. This > causes the pressure to rise and satisfy the Low Pressure Switch, so the > compressor kicks on again. The problem repeats from there, and the > compressor clutch kicks on and off due to activity of the Low Pressure > Switch. > > I've owned the vehicle for a year, and have done virtually nothing to it. It > has worked perfectly until today, when the AC elected to go offline. I have > no reason to suspect a leak at this time, but if the can of r134 does not do > the trick, then I'll need to take it somewhere for service. > > All I can do to the AC system is put the stuff in, and I have to ask to be > sure I have the process right. > > >
Reply to
L.W. (Bill) Hughes III
Loading thread data ...

For that he needs a gauge manifold with high and low gauges and a charging hose, which won't break the bank. A basic AC service and training manual will cost about $20.00. For R134a systems, "the only right way" to charge the system is to evacuate it with a charging station and then refill to the correct amount of refrigerant. People have gotten these systems working by guestimation though. If it is low enough to stop working it is pretty close to empty.

For tools,

formatting link
click on "Gauge Sets" and"Manuals". The Mastercool Basic Service Training Manual is great. It is somuch easier when you have some vague idea of what you are doing. Earle

formatting link
God Bless America, Bill O|||||||O> mailto: snipped-for-privacy@aol.com
formatting link

Reply to
Earle Horton

The short answer is; it's low on refrigerant Jeff. What vehicle is it? Does it have a sight glass?

Spdloader

Reply to
Spdloader

This depends tempature, humidity and A/C fan speed. It will likely be around 50 low to 250 or more high when first started on ahot day and may drop down to 25 to 30 low and 150 to 175 high when it is cooled out and blower speed is reduced. The higher the outside temps, the higher the pressure and 300 PSI or a bit higher is not rare on a R134 system on a hot startup

----------------- TheSnoMan.com

Reply to
SnoMan

Telling me it's a '95 Bronco tells me it doesn't have a sight glass.

Yes. It's kicking out when the system realizes that system pressure is too low. Saves your compressor.

It's undercharged. Impossible to tell how low from here, but I'd add a can, and you should get your cold back. I'd do that without gauges, and I have gauges and the whole setup. If it's low enough to give only the symptoms your describing, it'll hold a can. Try charging gas first, (hold can upright) you can tell it's moving if the can gets cold near the top. If it takes a while, like more than 15 minutes or so, flip the can upside down and hold for a few seconds at a time, charging with liquid, back and forth until the can is empty. You can feel the liquid inside sloshing, and you can tell when it's empty. Those trucks blow cold enough to "hang meat" when they're working right.

Spdloader

Reply to
Spdloader

I am not myself familiar with Ford systems but according to the Mastercool manual there are Ford systems (FFOT, no idea what this means) that are supposed to cycle the clutch, but not as fast as you are reporting. This does appear to be a case of low refrigerant. Basically, these systems run until a reservoir is full of liquid refrigerant, and then rest until it is exhausted. Typical cycle times are 2-3 times per minute at low ambient temperatures up to continuous running at high ambient temperatures. Yours is cycling much faster than this and probably low on refrigerant.

These Ford systems appear to be a little "different" in operation so maybe a Ford news group might be a good source.

Although I recommend a full manifold gauge set, there are setups intermediate between what you have now and hi-low gauges. A few years back I got a low side coupler, hose, gauge, valve and can tap from J. C. Whitney pretty cheap. I have seen similar rigs at Autozone. This lets you view the low side while filling at the same time. It doesn't show the high side, but it is a lot better than filling "blind".

Earle

Reply to
Earle Horton

Just double check the low side switch, as I didn't know the low pressure didn't work correctly until the next summer, (with help from a friend) after I had used up seven hundred dollars of R12:

formatting link
All I knew was I needed to jump it inorder to fill, where the normal cycling was enough to start the fill in thepast. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com

Reply to
L.W. (Bill) Hughes III

Sometime too if the hose is long enough you can put R134a can in a pan of hot water while trying to draw vapor from it because as liquid boils to gas in can it cools it a lot and when this happens the pressure in can drops and slows things down a lot on charging. The idea of flipping can as above is not a bad idea as I do it but limit is to a few seconds or so at a time so you do not get a slug of liquid in compressor.

----------------- TheSnoMan.com

Reply to
SnoMan

The problem is though that you cannot really tell the rue state of charge without seeing both sides at once. Using low side only is a guesstimate at best.

----------------- TheSnoMan.com

Reply to
SnoMan

In a class, we were allowed to shake it upright. God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com

formatting link

Reply to
L.W. (Bill) Hughes III

That is illegal in 37 states, including California.

Reply to
N. (Nancy) Huge IIIII

Another trick is to lay it on the engine valve cover.

Spdloader

Reply to
Spdloader

Or somewhere where the heat flow for raditor can help thaw the can and warm it up a bit as it tries to chill.

----------------- TheSnoMan.com

Reply to
SnoMan

I sure is coward, that's why I said class where the instructor is present. Forwarded for attempted forgery: snipped-for-privacy@shaw.ca, snipped-for-privacy@shaw.ca, snipped-for-privacy@sjrb.ca God Bless America, Bill O|||||||O mailto: snipped-for-privacy@aol.com

formatting link

Reply to
L.W. (Bill) Hughes III

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.