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BStone 
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Joined: 15 Sep 2009
Location: Texas
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 Topic: AC 8070 ac
Posted: 28 Aug 2011 at 10:26am |
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System is converted to 134a.Worked fine.Had a leaking comp. so I flushed the system and replaced the comp. and accumulator.Charged system.The low side will stay around 30 lbs.The high side will race to 450 + lbs rapidly.I can spray the condenser with a water hose and it will drop quickly to 300 lbs.When I quit spraying it will start rising quickly...Will go up about 25 lbs. and then drop a little and quickly rise 25 lbs higher each time.Cleaned the condenser out with high pressure water.Looks clean.No bent fins or nothing.Put the side hood back on to make sure it would be pulling the air through the condenser.I wouldn't let the high side get over 460 or so lbs.Didn't want to blow anything up.It appears the high side would keep rising to wherever if I didn't spray the cond. with water.Anybody have any ideas? It was 110 here yesterday and I need to get this tractor in the field.Thanks to any help.
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SLee(IA)
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Joined: 11 Sep 2009
Location: Polk City, Iowa
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Posted: 28 Aug 2011 at 10:55am |
Plugged expansion valve.
Steve
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BStone
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Posted: 28 Aug 2011 at 11:26am |
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Was thinking expansion valve or condenser.You think expansion valve?
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DrAllis
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Posted: 28 Aug 2011 at 12:20pm |
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How much freon ya got in it?????????????? 4 lbs would be too much........
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AllisFreak MN
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Joined: 07 Dec 2009
Location: Minnesota
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Posted: 28 Aug 2011 at 12:28pm |
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Don't they have a high pressure safety switch to prevent that from happening?
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'49 A-C WD, '51 A-C WD, '63 A-C D17 Series III, 1968 A-C One-Seventy, '82 A-C 6060, '75 A-C 7040, A-C #3 sickle mower, 2 A-C 701 wagons, '78 Gleaner M2
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BStone
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Posted: 28 Aug 2011 at 12:43pm |
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Pulled a vacum before putting any 134 in and had only 2 cans in when high side started racing up.Had the left hood off and thought it might not be pulling enough air from the condenser.Stopped and put hood back on.All the foam is in place so it can't be the air flow.When it ran to 400 lbs quickly I started spraying the water on the condenser and seen how fast it would start dropping pressure.Didn't know if it might be to low so I added the 3rd can , but the results were the same.I don't think 2 cans could be to much.
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BStone
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Posted: 28 Aug 2011 at 12:46pm |
 AllisFreak MN wrote:
Don't they have a high pressure safety switch to prevent that from happening? |
Yes but as fast as it goes up it's evident that something is wrong.I don't think it's good to let it get 450 +.A lot of times when the high pressure safety valve blows open to release pressure they will sometimes leak.
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Orange Blood
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Location: ColoradoSprings
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Posted: 28 Aug 2011 at 12:52pm |
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I agree with a pluged expansion valve. When flushing any system with an expansion valve I remove and flush the valve by hand, it also has a screen in it, that must be cleaned. The worst thing that was ever invented is Dyed Freon/Refrigerant, that stuff is ok, in small amounts, but some people tend to put way too much in, and it will always plug a valve if there is any other contaminat in the system, as it binds with the dye, and gets carried to the expansion valve and it's screen.
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Still in use:
HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060
Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7
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MACK
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Posted: 28 Aug 2011 at 9:20pm |
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If expanson valve was pluged, the low side should be in a vacum. Does it cool? MACK
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Orange Blood
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Posted: 28 Aug 2011 at 9:28pm |
An overfilled system will still have some pressure on the low side when the expansion valve is plugged. A correctly charged system will still have some pressure on the low side if the expansion valve is almost plugged.
However since we all jumped on the plugged valve, Mack does offer a very good question about the temp of the evap?
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Still in use:
HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060
Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7
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BStone
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Posted: 28 Aug 2011 at 9:33pm |
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Yes It cooled ok.But I had to keep water on the condenser to keep it at 375 lbs.I'm sure with water on the condenser it would make the cooling better.
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Jordan(OH)
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Posted: 28 Aug 2011 at 9:38pm |
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Needs to run about half throttle to get enough air across it. were you checking at idle?
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Bee
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Posted: 29 Aug 2011 at 5:23am |
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How long did you pull the vacuum prior to charging?
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Bob, North Carolina
1949 B
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