time to put the ac to bed

[tim berry]

after putting the cordoba back on the road I went through the ac system and converted it to 134a replaced all the hoses, dryer, expantion valve ,compressor, and all the gaskets. I flushed the condenser and evaporator . I put the system under vacuum and let it set for 12 hrs., no leaks . I filled the system with the proper amount of 134 a and the ac was nice and cold after about a week the clutch started to cycle like it was low on 134 threw the gages on and it was not low. so I figured the condenser was plugged so I got a new one the one I just installed has some really small tubes im thinking restriction any ideas just fat old man that wants to be cold thanks in advance

 

[Monkeyed]

did you put the right oil in?

 

[Monkeyed]

the tubes, are suppossed to be small, the restrictions are there to make the compressed refridgerant expand as it exits the high pressure side through the expansion valve, causing the temperature to drop. has something to do with the molecule's spacing.

http://www.autoair.ie/types.html

 

[Monkeyed]

replacing the hoses wasn't necassary btw. the old R-12 had gigantic molecules compared to the R-134, so the hoses were made to be more porous, when new, so over time the R-134 would seep out. But once the systemhas been run for a while, the oil circulates through coating the hoses, making a barrier. you wouldn't want to use new R-12 hoses, but old ones that have been run, are fine.

not that it pertains to your current problem,

 

[joeblo]

Check the low pressure switch with a meter and see if it is cycling on low pressure. If it is and the pressures aren't dropping below switch set point then you have a bad switch. If the pressures are dropping below set point than you need to check refrigerant sub cooling to see if you are supplying enough refrigerant to the metering device. If you don't have any sub cooling than it is low on charge, if you have to much sub cooling than it may be restricted. Restriction may be in the filter, (should be no temperature drop across filter), or in the metering device. With out knowing pressures, temperatures, sub cooling, and superheat, than its just a lot of guessing. Condensers rarely plug up and when they do its a much bigger problem than just the condenser. when you vacuumed the system did you use a micron gauge? 12 hours is a long time to leave on a vacuum, it may have pulled in some moisture. I realize this may not be a lot of help, but its hard to build a puzzle with out all the pieces.

 

[tim berry]

thanks for the input guys I originaly use pag 100 oil and almost 3 cans of 134a the low pressure switch is the only part I don't remember replacing the old condenser has some big tubes ,and the new one has small tubes (restriction)? now im waiting on a new compressor because I broke the old one (also had a leak in the front shaft seal ).

 

[tim berry]

First thanks to joeblow for the info ! First thing the rebuilt compressor was bad ,second was the expantion valve was about 1/3 closed ( i didnt know they were adjustable ) . I replaced the compressor with a new one not rebuilt , pulled vaccume for about an hour let it sit for awhile no leaks , i charged the system and all is cool ! The best part i got an education