2nd Gen Non-Engine/Transmission need a/c specs for pressures

[CEdwards]

I searched everywhere on here but could only find 21 posts about air conditioning. My question is what is the high and low pressure supposed to be on the low side where you add freon when the compressor is cycling? Also, about how often should it kick on and off or where can I find this info?

 

[Bob4x4]

The pressures will vary with temps,easiest way to get it right is to reclaim,evac and recharge with the correct weight. Below 70 degrees ambient it's all a crap shoot anyway.



Bob

 

[B.G. Smith]

First, with everything else operating ok, the clutch cycling switch will open at 25# and close at 43# suction pressure. With correct refrigerant charge, engine running at 1000 rpm and outside temperature of 80 deg. the suction pressure should be 40-50 psi, discharge pressure should be 175-215 psi and air coming out of center panel outle should be 55-60 deg. Note: If pressures are lower than shown, but center panel temp. is ok than system is ok. From 99 FSN. bg

 

[Bob4x4]

It was high of 56 yesterday in OK city and low of 37. Pressures will not be valid:-laf



Bob

 

[B.G. Smith]

It was high of 56 yesterday in OK city and low of 37. Pressures will not be valid:-laf



Bob

Read "Outside temperature at 80 deg. " It will probably be a few days before you see 80 deg. in Oklahoma depending on what part you reside in but if it is above 70 the temperatures posted won't be that much lower, especially the suction, probably less than 10 psi. If the unit is low on refrigerant, it needs to be correctly charged because it runs in the winter time too on defrost mode. bg

 

[CEdwards]

Thanks for the replys, I don't know that much about a/c. I was trying to diagnose my problem and maybe do the labor to fix mine then take it in to get evacuated and recharged. When I bought my truck used it had a sticker under the hood from about 4 months previous saying it had been recharged with die. It was ice cold all summer. Then the next summer comes and not so cold unless running down highway, by end of summer not working hardly at all in 100 degree heat. So, I assume low on freon because it must have a leak. I buy a bottle with gauge on it to get me by for a while and when I put it on the pressure is about 80psi dropping to 50psi when compressor cycles which was pretty frequent (95 degrees outside) so I thought maybe it had a plugged line or something else. I would appreciate any advice as to how to go about diagnosing the problem. If I have a leak in some place like under the dash that recquires a lot of labor I would rather do it myself. By the way I did clean my radiators out at the car wash and it didn't help.

 

[B.G. Smith]

What you experienced with the can of refrigerant sounds normal. With the valve open on the can, you are reading somewhere between the suction pressure of the system and the vapor pressure in the can. If you close the valve you will probably see the pressure going to 25 or lower then the compressor will cut off, when the pressure rises to around 45 it will come back on. If the unit is short cycling and not cooling it is probably low on refrigerant. The system only holds around 32 ounces. Yes, if it is low you have a leak but it could be just the seal on the compressor or a connection on one of the lines somewhere. Usually if a leak is very bad you can see oil residue where the leak is. I'm not a big fan of adding dye to the system. Some old nut told us in school about 40 years ago that only refrigerant and oil should be put into the system. Hope you can get it worked out. bg