A/C not cooling?

[500snakz]

My a/c is not cooling in this 98* temps. I put in a whole large can of 134 and it still is not cold. The air is sorta cool but not cold. Pressure in high side is about 48-50lb. Anyone know what the pressure is supposed to be or what is wrong?:dontknow:

 

[wesalbert]

Depending on temperature, I believe the pressure is supposed to be around 50-55. I'm sure someone more qualified than me will chime in.

 

[Need for Speed]

My a/c is not cooling in this 98* temps. I put in a whole large can of 134 and it still is not cold. The air is sorta cool but not cold. Pressure in high side is about 48-50lb. Anyone know what the pressure is supposed to be or what is wrong?:dontknow:

Man, 101 here today and I have the same problem...cool but not cold air coming out...

 

[eddie102870]

needs a vacuum pulled on it. make sure its a newer machine too. we get back trucks every time and have to re do them. older machines putting too much oil in the system causing them not to cool.

 

[WOT]

I believe the high side should be somewhere between 200 - 300 psi. I don't know the specs for our trucks, but Freon 134a runs fairly high on the high (hot side). On the low side, it should be somewhere between 32-45 psi. If it is above 50 psi, it will not get very cold.

Here are the pressures vs temperature on the cold (low pressure) side. You can see that if the low side is in the 50+ psi range, the freon will not get very cold. If the low side were to go to 27 psi or below, you would form ice on your evaporator.

PSI Temp (degrees F)

27 31.10F
28 32.27F
29 33.43F
30 34.56F
31 35.68F
32 36.77F
33 37.85F
34 38.91F
35 39.96F
36 40.99F
37 42.00F
38 43.00F
39 43.98F
40 44.95F
41 45.91F
42 46.85F
43 47.78F
44 48.70F
45 49.61F
46 50.51F
47 51.39F
48 52.26F
49 53.13F
50 53.98F
51 54.82F
52 55.65F
53 56.48F
54 57.29F
55 58.10F

 

[wesalbert]

I believe the high side should be somewhere between 200 - 300 psi. I don't know the specs for our trucks, but Freon 134a runs fairly high on the high (hot side). On the low side, it should be somewhere between 32-45 psi. If it is above 50 psi, it will not get very cold.

Here are the pressures vs temperature on the cold (low pressure) side. You can see that if the low side is in the 50+ psi range, the freon will not get very cold. If the low side were to go to 27 psi or below, you would form ice on your evaporator.

PSI Temp (degrees F)

27 31.10F
28 32.27F
29 33.43F
30 34.56F
31 35.68F
32 36.77F
33 37.85F
34 38.91F
35 39.96F
36 40.99F
37 42.00F
38 43.00F
39 43.98F
40 44.95F
41 45.91F
42 46.85F
43 47.78F
44 48.70F
45 49.61F
46 50.51F
47 51.39F
48 52.26F
49 53.13F
50 53.98F
51 54.82F
52 55.65F
53 56.48F
54 57.29F
55 58.10F

Good info to know :rock:

 

[500snakz]

Going to get a vacuum pulled and see if that does the trick. WOT i should have said LOW side. Sorry.

 

[ACE]

ac warm?

I bielive that one of the problems or trucks have is that there is a large gap between the radiator and the condenser, this causes poor cooling in traffic. when the ac relies on the cooling fan for air movment across the condenser, but while driving down the road there is more than enough airflow, so if your truck has a cooling issuse in traffic then this could be your problem, a supplamental cooling fan Ie. small electric fan installed onto your condenser would do alot to help with register temps in traffic, you could use a "high side tee" to tap into the discharge side of the system and use a high psi cut off switch to turn on the fan automaticly in traffic when the disscharge psi reaches say 60-75% of the max , I have done this before on several vehicals when repalcing the mecanical fan with an electric one.. I would have to do some reserch to get the exact psi needed to set up the fan but it is possible..
Joe:rock: :rock: