A/c Temperature

[markss106]

1999 Yukon. New GM compressor and dryer and orfice tube. System was completelt flushed and evacuated. Filled with 2lbs 12 oz of r-134 (Has rear air) . All lines on engine feel cold and pressure readings are 26 low and 175 high. Temp coming out vents will only get down to 55 degrees. Also the recirculate inside air door is working. The air coming out the vents should be about 10 degrees colder. Any suggestions would be appreciated on whats wrong.

[Carder09]

Uh, 55deg. seems pretty cold to me, I know when I drive my a/c gets colder, but not when sittin and idling.

[markss106]

55 does sound cold but its not quite cold enough. Temp of air coming out vents should be around 45. I have just found out that the parts guy give me an orifice for a Yukon without rear air. Mine has rear air. Iam going to reclaim freon install correct orifice evacuate system and recharge to see if this corrects the problem. Also has anyone run across this same situation? Thanks again for any help

Uh, 55deg. seems pretty cold to me, I know when I drive my a/c gets colder, but not when sittin and idling.

[Debo511]

Your duct temp will be directly related to outside temperature and humidity.

[Debo511]

Refer to chart below:

 

 

A/C Performance Table - Gas Engine With Electric Cooling Fan or RPO HP2

 

Ambient Air Temperature

Relative Humidity

Service Port Pressure

Maximum Discharge Air Temperature

 

Low Side

High Side

 

13-18°C (55-65°F)

0-100%

165-257 kPa (24-37 psi)

830-1180 kPa (120-171 psi)

10°C (50°F)

 

19-24°C (66-75°F)

Below 40%

185-290 kPa (27-42 psi)

1010-1340 kPa (147-194 psi)

11°C (52°F)

 

Above 40%

202-313 kPa (29-45 psi)

990-1370 kPa (144-199 psi)

13°C (55°F)

 

25-29°C (76-85°F)

Below 35%

225-319 kPa (33-46 psi)

1180-1470 kPa (171-213 psi)

14°C (57°F)

 

35-50%

238-330 kPa (35-48 psi)

1180-1490 kPa (171-216 psi)

14°C (57°F)

 

Above 50%

248-352 kPa (36-51 psi)

1190-1520 kPa (173-221 psi)

16°C (61°F)

 

30-35°C (86-95°F)

Below 30%

257-359 kPa (37-52 psi)

1320-1610 kPa (192-234 psi)

17°C (63°F)

 

30-50%

267-375 kPa (39-54 psi)

1340-1650 kPa (194-239 psi)

18°C (64°F)

 

Above 50%

281-399 kPa (41-58 psi)

1360-1710 kPa (197-248 psi)

20°C (68°F)

 

36-41°C (96-105°F)

Below 20%

290-393 kPa (42-57 psi)

1480-1760 kPa (215-255 psi)

19°C (66°F)

 

20-40%

298-411 kPa (43-60 psi)

1500-1820 kPa (218-264 psi)

21°C (70°F)

 

Above 40%

313-429 kPa (45-62 psi)

1540-1880 kPa (224-273 psi)

22°C (72°F)

 

42-46°C (106-115°F)

Below 20%

327-428 kPa (47-62 psi)

1650-1910 kPa (239-277 psi)

21°C (70°F)

 

Above 20%

336-448 kPa (49-65 psi)

1680-1980 kPa (244-287 psi)

23°C (73°F)

 

47-49°C (116-120°F)

Below 30%

367-474 kPa (53-69 psi)

1830-2100 kPa (266-305 psi)

25°C (77°F)

[asc08]

I am an engineer who designs commercial building HVAC systems. We typically design building systems with 55 degree air coming off of the evaporator coil. At 55 degrees, most of the moisture has been removed from the air in the form of condensate.

 

Vehicle HVAC is not as closely controlled as building HVAC. Your vehicle is more susceptible to ambient conditions (outside temp and humidity) than a large building. Your vehicle system was designed to have air flowing over the condenser as the vehicle moves, not just from the fan. So on a really hot and humid day, you may notice the air coming out of your vents getting warmer while you are stopped in traffic, and it will cool down as the vehicle starts moving again.

 

Also, your system (if you are not running on recirculate mode) will be pulling 100% outside air into the cabin. The more heat and humidity in the air, the harder the system has to work (both on the evaporator and the condenser). So if you get 45 degrees out of the vents on a more mild day (which is entirely possible, if not probable), you most likely will not get 45 degrees out of the vents on a hot, humid day.

 

Just wanted to give you a few thoughts, although, if you are not satisfied with how it works, have at it!

[markss106]

Thank you guys for all the technical advice I guess I'm expecting just a little to much

I am an engineer who designs commercial building HVAC systems. We typically design building systems with 55 degree air coming off of the evaporator coil. At 55 degrees, most of the moisture has been removed from the air in the form of condensate.

 

Vehicle HVAC is not as closely controlled as building HVAC. Your vehicle is more susceptible to ambient conditions (outside temp and humidity) than a large building. Your vehicle system was designed to have air flowing over the condenser as the vehicle moves, not just from the fan. So on a really hot and humid day, you may notice the air coming out of your vents getting warmer while you are stopped in traffic, and it will cool down as the vehicle starts moving again.

 

Also, your system (if you are not running on recirculate mode) will be pulling 100% outside air into the cabin. The more heat and humidity in the air, the harder the system has to work (both on the evaporator and the condenser). So if you get 45 degrees out of the vents on a more mild day (which is entirely possible, if not probable), you most likely will not get 45 degrees out of the vents on a hot, humid day.

 

Just wanted to give you a few thoughts, although, if you are not satisfied with how it works, have at it!