a/c question

[Chris05]

So I recharged my system and got it to work somewhat couple questions though.
My compressor is kicking in and out alot especially when at higher rpms and i lose the cooling. It is colder at idle.
So did i put in to much r-134a or not enough
What is the capacity of the system on a 1995 f-250

I guess i dont understand the pressure switch does it kick it out when it gets to high of pressure meaning there is to much or does it only kick it out when there is not enough pressure how does it regulate it and know when to kick the compressor in and out
Thanks
Chris

[Rodslinger]

Bump for some AC help.

[puttinoutsmoke]

sounds as if yoou dont have enough 134 in the system yet...the pressure switch kicks the compressor off when the system is too low on freon so that the compressor does not burn up...not sure about how many cans exactly...most the time there is a sticker on the core support that will say others it is on the hood...but id guess about 3 1/2-5 cans...that is an estimate...btw if your system was completly empty did you vacuum it down and add pag oil ? hope this lil info helps you some...im in texas and i wont drive anything without air...

[gbear]

I don't Have my Service manual here but I'll get it tomorrow and give you the amount of charge. It sounds like you have too much charge. How did you arrive at the Charge you have now? I had to replace the hose from the accumulator to the compressor on My 95 F250 and I weighed in the charge.
When I see my manual I'll tell you the amount.

[Chris05]

I bought a kit form interdynamics and it came with the gauge i used all three cans and arrived at 20lbs of pressure the system was already purged since it had all leaked out i checked the high and low end so i began adding freon the valve was stuck open so i lost some of the first can if not most of it so thats how i got to where i am now it does blow cold but when you step on the pedal the compressor kicks out and in.

[Chris05]

Okay i just added one more can and it is more consistently running now still kicks in and out more than i think it should i am at about 25 lbs and it is ice cold at an idle still would like to know what the recomended amount is and pressure for the system.

Sure am glad to see some progress in the system though it didnt work last summer and i was scared to foot the bill to have it checked out and change over to r134a The kit i got was a breeze to use and sure was worth the 50 bucks.

[mschn99]

2 pounds 6 ounces should be the spec......Marc

[gbear]

Under the hood of my truck (95 F250) on the lable on the core support it says 2lbs and 6 oz max charge. as Marc has already said. In my service manual is tell me that the charge is 2 lbs and 1 oz (+ or - 1 oz). I know this caused me some confusion when I was working on my truck. I was working with a totally evacuated system (Vaccum down and checked for 15 minutes).
I weighed in 2 lbs. and 2 oz's to allow for loss with the removal of gages) The system is working for over 16 months just fine. I check the center registers of the truck several times and during freeway driving have the temps running 38 for low and cycling to 44 on the high during the cycle.
Like the lable say's I think that is a max charge and the service manual is a mininum charge. I hope this was of some help. I made a pdf file of the page in the service manual but don't know how to attach it to this reply. There is a chart in the manual that deal with the pressures but it is temperature dependent. If the gages you are using have temperature on them you will see what I am Talking about the High side pressure will correspond with the condenser temp and the low pressure side will correspond with the evaperator temp. According to the service manual the Switch on the Accumulator/ Dryer is the low pressure switch or as the book calls it (A/C cycle switch) it bring the compressor clutch in at 23 psi on the lows side. I also cycles it off at between 40 and 47 psi on the low side (the cab is cool temp). I have a black truck and live in the South, and A/C is on the the list of thing I want to work Right. I hope this helps.

Jim (gbear)

[mschn99]

as far as the charge wieght Gbear.....the 1994 and early build 1995's had a charge weight of 2lbs 1oz.........but then ford released a TSB saying to put them all at 2lbs 6oz.....so the manual you have must have just not got updated with fords change in the charge weight........i cant access the manual for anything older than 96 online so i had to reference the TSB just to post the spec.....thats the only reason i know this.......Marc

[gbear]

When I was doing the work on my truck I didn't know so I just went with the lower level. But what you say explains alot about some of the things I read.
I was more worried about an overcharge than a under charge. I think my manuals were printed in July of 1994.
Thanks again