1-3-2-4 Posted June 24, 2010 Share Posted June 24, 2010 So I'm looking at the service manual for my 1995 Legacy and in one area it talks about charging liquid refrigerant in the high side first I added the first can and purged the hose (I already did a vacuum) So I open the High side fully and the high side gauge goes up to a little above 110 psi but it still has a lot of refrigerant in the can? It also says when both high and gauge are about equal or the can is empty the system has been filled to specifications. Did I do something wrong? The low side is still reading a vacuum with the first can added but still refrigerant is in the can upside down. Link to comment Share on other sites More sharing options...
nipper Posted June 24, 2010 Share Posted June 24, 2010 WTF Are you sure you read that right? You never ever never ever add anything to the system on the high side. This is very dangerous. You can blow up the can or worse. Coolant is always added to the low side. http://www.aa1car.com/library/ac_recharging.htm Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 24, 2010 Author Share Posted June 24, 2010 I quote you from the service manual... Car is off.. "Evacuating & Charging" 3) The charging procedure described in this section begins by charging liquid refrigerant into the high pressure side of the system with the engine OFF. The procedure is completed by charging refrigerant VAPOR into the low pressure side of the system with the engine running. Few pages ahead "Inital charging through the high side" Connect tach to engine 2) WITH THE ENGINE OFF, start charging by slowly opening the high presure manifold valve. Down a few spots it says: "Check gauge readings" When both high and low pressures gauge readings are about equal, or the HFC 134a source is empty, or the system has filled to specifications, close the high press manifold valve. I guess my mistake was opening the high too quick? Not sure how slow is slow. Link to comment Share on other sites More sharing options...
nipper Posted June 24, 2010 Share Posted June 24, 2010 You are using a silly 1 lb can from the store. The dealer useses a can that is the size and stronger then a propane tank. No dealer uses 1 b cans. You want to blow your hand off go right ahead. If they do use a 1lb can it is always on the low side. Every other instructions you will find on the net will tellyou IT IS DANGEROUS. Every site, INCLUDING (usually) the can will tell you not to connect to the high side. Just because the manual syas X it is NOT safe to assume the dealer is using the same equipment. They use a very expensive recycling machine that evacacutes refregeriant, cleans it, filters it then pressurizes it in a propane size tank. I have an AC license. You want to blow up the can go right ahead, you have been warned. Link to comment Share on other sites More sharing options...
Scoobywagon Posted June 24, 2010 Share Posted June 24, 2010 Nipper is quite right. Charging on the high side from a can is a bit of a no-no. Having said that, you've already gotten started this route and you can't really undo that. So here's my advice. You've added liquid to the high side, so you're going to show high pressure on the high side and little or nothing on the low side. That's because the refrigerant can't flow backwards through the compressor and the only direction for it to expand is through the expansion block. It'll take a while to equalize, but it will. Your guage should have a valve just above the fitting. Turn that off and put the can on the low side to finish charging that can. Then start the engine and run the A/C on high. That should get it straightened out. Link to comment Share on other sites More sharing options...
capn_r Posted June 25, 2010 Share Posted June 25, 2010 So I'm looking at the service manual for my 1995 Legacy and in one area it talks about charging liquid refrigerant in the high side first I added the first can and purged the hose (I already did a vacuum) So I open the High side fully and the high side gauge goes up to a little above 110 psi but it still has a lot of refrigerant in the can? It also says when both high and gauge are about equal or the can is empty the system has been filled to specifications. Did I do something wrong? The low side is still reading a vacuum with the first can added but still refrigerant is in the can upside down. It sounds like it's possible that your expansion valve is stuck shut. If that is the case if you charged the remainder of your can into the low side (with the vehicle running, if a low pressure control will allow the clutch to operate with the valve on the can at the top to feed vapor) it will probably drop the low side pressure until the low pressure control opens and stay off on low pressure. It seems like the expansion valve should feed enough to bring the low side pressure up fairly quickly and with yours staying in a vacuum on the low side to me that points to that valve not functioning. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2010 Author Share Posted June 25, 2010 what pressure is needed to turn the compressor on? the low is at 40 and the high is 110 psi Link to comment Share on other sites More sharing options...
capn_r Posted June 25, 2010 Share Posted June 25, 2010 what pressure is needed to turn the compressor on? the low is at 40 and the high is 110 psi It may tell you in your FSM, the only one I have atm is for an older vehicle with a R-12 system but the low and high side switch pressures are listed in section 4-7 under "specifications" in the manual I have. My guess would be that the low pressure switch should be closed at 40 psi though. Have you tried feeding it some vapor in low side with the dash controls calling for cooling? Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2010 Author Share Posted June 25, 2010 (edited) It may tell you in your FSM, the only one I have atm is for an older vehicle with a R-12 system but the low and high side switch pressures are listed in section 4-7 under "specifications" in the manual I have. My guess would be that the low pressure switch should be closed at 40 psi though. Have you tried feeding it some vapor in low side with the dash controls calling for cooling? yes I have.. I went more then 40 psi.. I also jumped the pressure switch and the compressor came on but still no cooling. also the manual shows the pressure switch for the high line but I can't tell if it's on at 200+ or what. Edited June 25, 2010 by 1-3-2-4 Link to comment Share on other sites More sharing options...
capn_r Posted June 25, 2010 Share Posted June 25, 2010 yes I have.. I went more then 40 psi.. I also jumped the pressure switch and the compressor came on but still no cooling. also the manual shows the pressure switch for the high line but I can't tell if it's on at 200+ or what. QUOTE] What were your pressures when you jumpered the pressure switch? That pressure switch schematic with the various SI units as well as psi is confusing. I think it is saying the high side closes at 213 + or - and opens at 384 + or -. Have you been able to get the suggested amount of refrigerant into it? Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2010 Author Share Posted June 25, 2010 yes I have.. I went more then 40 psi.. I also jumped the pressure switch and the compressor came on but still no cooling. also the manual shows the pressure switch for the high line but I can't tell if it's on at 200+ or what. QUOTE] What were your pressures when you jumpered the pressure switch? That pressure switch schematic with the various SI units as well as psi is confusing. I think it is saying the high side closes at 213 + or - and opens at 384 + or -. Have you been able to get the suggested amount of refrigerant into it? My pressures where 40 psi low and 105 high Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2010 Author Share Posted June 25, 2010 I ordered a new expansion valve this morning.. here are pictures from yesterday Link to comment Share on other sites More sharing options...
Timberwolf530 Posted June 25, 2010 Share Posted June 25, 2010 (edited) I took the original post to say that he was adding refrigerant to the low side, while monitoring the high side with a high side guage. It's impossible to add to the high side anyway. The quick connect on the high side is larger than the low side connector. Even if you could attach it, nothing would come out of the can because the pressure in the system is higher than the pressure in the can, and it could possible explode the can. Pressure to activate the compressor depends on ambient temperature. Use a jumper sparingly, if at all. Normally it will kick in by itself after the pressure comes up enough. It may take awhile, but it usually goes by itself. if you jump it and run the compressor with low pressure too long, it will damage it. The higher the temp, the more pressure you need. 40 psi on the low side should be enough to trigger it unless it's really hot out. Your high side pressure should be somewhere over 200 psi, not sure exactly on Subies yet, but 100 seems really low. I never had to work on A/C for the other two I owned. Anyway, if pressure on the low side is within limits, but is that low on the high side with the compressor running, it suggests there is something wrong with the compressor. Edited June 25, 2010 by Timberwolf530 Link to comment Share on other sites More sharing options...
nipper Posted June 25, 2010 Share Posted June 25, 2010 He said he was doing as per the FSM Evacuating & Charging" 3) The charging procedure described in this section begins by charging liquid refrigerant into the high pressure side of the system with the engine OFF. The procedure is completed by charging refrigerant VAPOR into the low pressure side of the system with the engine running. Link to comment Share on other sites More sharing options...
Timberwolf530 Posted June 25, 2010 Share Posted June 25, 2010 I would like to read that whole article to understand what they're talking about, because what I see there doesn't make any sense to me. If you hold the can upright, you get vapor, upside down, you get liquid. I personally have never added anything to the high side, although, as long as the compressor is not running, it's not dangerous if you can get a connector that fits. I can't remember the exact sizes, but the high side connector is 3-4 mm larger. That's why I'm having a hard time understanding what they mean. The only time the two pressures should be the same high and low, is when it's not operating. Anyway, my main point is, with the compressor running, if your low side pressure is within limits, but the high side is not, you have a compressor problem. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2010 Author Share Posted June 25, 2010 I will see if I can post the PDF since Canon was smart not to make windows 7 drivers for a scanner is now useless for me. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 25, 2010 Author Share Posted June 25, 2010 Here is the PDF of the charging section MSA5TCD95L5728.rar Link to comment Share on other sites More sharing options...
SubieDaddy80 Posted June 25, 2010 Share Posted June 25, 2010 After reading this, remind me to never try doing the A/C charging myself! lol. I am definately leaving that to the dealer and the pros! Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 27, 2010 Author Share Posted June 27, 2010 looks like I got a blockage I have my money on the expansion valve (new one will be here Monday) I will flush the system out on Monday. I wonder if the blast of heat from the torch did the rest of it in? I had to break the tight grip the threads had. Link to comment Share on other sites More sharing options...
abog Posted June 27, 2010 Share Posted June 27, 2010 Definitely not a good idea to use a torch on a/c components. Most of these parts are aluminum and can easily be damaged. Nipper is correct on his warning, never fool with the high pressure side with the small cans. If the system is not running you should be ok, but it is a bad habit to get into. All it would take is one mistake and you could be seriously hurt. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 27, 2010 Author Share Posted June 27, 2010 Definitely not a good idea to use a torch on a/c components. Most of these parts are aluminum and can easily be damaged. Nipper is correct on his warning, never fool with the high pressure side with the small cans. If the system is not running you should be ok, but it is a bad habit to get into. All it would take is one mistake and you could be seriously hurt. I'm not dumb enough to run the car with the high side open.. anyone who does that should diaf. Link to comment Share on other sites More sharing options...
1-3-2-4 Posted June 28, 2010 Author Share Posted June 28, 2010 Link to comment Share on other sites More sharing options...
oldgray1 Posted June 28, 2010 Share Posted June 28, 2010 Sounds like he is describing charging into a vacuum or evacuated system using a gauge set. With the engine not running, sounds reasonable. I would echo the above statement about not getting into the habit of charging into the high side. I would imagine that over the years many DIY A/C charges have ended in disaster for that reason. Probably the reason the home kits for 134A have only a low side connector. Link to comment Share on other sites More sharing options...
capn_r Posted June 28, 2010 Share Posted June 28, 2010 Sounds like he is describing charging into a vacuum or evacuated system using a gauge set. With the engine not running, sounds reasonable. I would echo the above statement about not getting into the habit of charging into the high side. I would imagine that over the years many DIY A/C charges have ended in disaster for that reason. Probably the reason the home kits for 134A have only a low side connector. Agreed. Domestic vehicles in the 70's (R-12 systems)began having a different fitting on the high side on them for I'm sure that reason. But as you stated, charging into the high side on an evacuated system can't be a problem with pressures as the can pressure would be reduced until the can and system pressure stabilized. Link to comment Share on other sites More sharing options...
nipper Posted June 28, 2010 Share Posted June 28, 2010 Sounds like he is describing charging into a vacuum or evacuated system using a gauge set. With the engine not running, sounds reasonable. I would echo the above statement about not getting into the habit of charging into the high side. I would imagine that over the years many DIY A/C charges have ended in disaster for that reason. Probably the reason the home kits for 134A have only a low side connector. Never underestimate the ability of a human being to get around a saftey device. nipper Link to comment Share on other sites More sharing options...
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