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Post by Dave-ECIA on Jul 11, 2011 16:18:35 GMT -5
Ok, for those of you following along at home.....
I finally got the repaired tubing installed in my pickup today. Put the vacuum pump on and pulled it down to 30inHG, turned it off and watched the gauge. Held 30" for 3hrs. (No, I didn't sit there and watch the whole time, duh)
Put a partial can of 134a in the system prior to starting it up. Pulled in maybe 4oz. Started the engine and A/C and began to re-fill the system.
Here is where it gets interesting..... I filled the system until it got to 228psi on the high side. The chart I found said for the ambient temp today, that is where the pressure should run. The low side ran 38-40, which seems high?? And it probably only took 16oz of 134a to get to that point. The vent air temp was in the 58 to 60 degree range.
Is this right?? Seems like it should have taken more 134a to fill an evacuated system, but I'm not sure of the capacity.
Anyone want to take a stab at it??
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Post by MoJeeper™ on Jul 11, 2011 20:16:09 GMT -5
Just out of curiosity why didn't you just refill it to capacity since you had it completely empty? How long did you vac it for?
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Post by Dave-ECIA on Jul 11, 2011 20:29:03 GMT -5
I guess that is my question.. what is the capacity. poked around a little and couldn't find it.
only took a minute to pull down to that vacuum, then left the pump run for a couple more minutes. pulled the quick connect off the high side port and left the low side on to read vacuum.
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Post by MoJeeper™ on Jul 11, 2011 20:31:13 GMT -5
Need to find out the capacity and just fill it. When I Vacuum out a system, I usually leave it on there at least and hour, that way it takes out any of the moisture in the system.
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Post by jd9600guru on Jul 11, 2011 20:37:14 GMT -5
Question........ with all this opening of the system/leakage have you put any oil back into the system? Has the receiver dryer been replaced in the last few years?
As far as pressures........ I think you're in the ballpark for 134a...... what is your vent air temp running down the highway? Was the 58-60 you reported sitting still? How cold is that low side line getting? On a hot day like today you should still be able to get it frigid to the touch and get condensate on it.
See where you're at temp wise (vent) running about, if you dont think its cooling enough then add a bit more. You can always uncharge a bit if need be.
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Post by MoJeeper™ on Jul 11, 2011 20:42:36 GMT -5
I can never go by the pressures. Heck my jeep builds 400#+ on a 85degree day. BTW it has awsome AC
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Post by jd9600guru on Jul 11, 2011 20:50:37 GMT -5
I can never go by the pressures. Heck my jeep builds 400#+ on a 85degree day. BTW it has awsome AC Totally dependent on the system......... a smaller system will be running higher pressures than a system with a bigger cond./evap/ will. Thats why I kinda like to know system specs so you have an idea of where the "sweet spot" will be. 75% of the time I'll get a call to mess with an a/c and I have no data to help out so you just learn to do it by pressures output temp and feel. If Dave didn't change the receiver, I would be willing to be some liquid refrig was still in it even after drawing it down. So thats why it only took a pound to bring it right up. |
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Post by acfarmer on Jul 11, 2011 21:01:16 GMT -5
I guess that is my question.. what is the capacity. poked around a little and couldn't find it. only took a minute to pull down to that vacuum, then left the pump run for a couple more minutes. pulled the quick connect off the high side port and left the low side on to read vacuum. 2 - 2 1/4 lbs is what it holds Dave. |
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Post by Dave-ECIA on Jul 11, 2011 21:28:19 GMT -5
No, have not changed the receiver. Never thought about residual liquid in the system, just figured it was all gone due to the leak.
Yes, I added some oil after I replaced the tube, before I evacuated it.
I checked the vent temp sitting still. Going down the road, it damn near froze me out on MAX setting.
The low side was very cold to the touch and condensate was running off, in no part thanks to the 85% humidity we enjoyed today.
Trent, you thinking I didn't leave the vacuum pump on long enough?? I guess I'm only out one can of refrigerant if you think that's the case.
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Post by acfarmer on Jul 11, 2011 21:32:58 GMT -5
Sounds like it working fine to me.
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Post by jd9600guru on Jul 11, 2011 21:55:13 GMT -5
Sounds like it working fine to me. Amen, ac............ Dave you're offically an a/c pro |
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Post by MoJeeper™ on Jul 11, 2011 22:03:54 GMT -5
Working going down the road, sounds like it's fixed/ kinda. May need to look at your fan clutch for it to work sitting still. Some systems just don't seem to work sitting still. Not vacuuming it long enough is not the problem, but it is a good idea to leave it on there for awhile, it will boil the moisture out that way.
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Post by acfarmer on Jul 11, 2011 22:39:54 GMT -5
Older chevys are good for not working when Idling. my 91-92 and 95 were and are that way.
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Post by acfarmer on Jul 11, 2011 22:41:01 GMT -5
You might make sure when its idling that its not kicking the clutch in and out continously. That is a sign you dont have enough freon in it.
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Post by Dave-ECIA on Jul 11, 2011 22:47:21 GMT -5
It ran almost continually this afternoon while sitting, coldest setting, fan on high and set to Max (recirculate). It wasn't cycling much, maybe 90% on, 10% off, but that's just a guess.
Trent, are you suggesting that I should have left the vac pump run longer? How do you know when it's long enough??
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