Low Pressure valve
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Joined: Apr 2011
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From: Philadelphia
Low Pressure valve
Anyone have a picture of what this looks like on a '79? I know I'm missing something obvious. I see my high and low pressure hoses coming out of my condenser and I follow them back until I can't see them any more, but I see no valve stems anywhere.
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Joined: Apr 2009
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From: Stanley, VA
On the York compressor the charge valves are on the fittings at the compressor. The hoses themselves don't have valves.
In the (not too clear) picture, follow the hoses to the compressor, they hook to square blocks. On top of these blocks are acorn nuts. These are covers for the valves. Take them off. This will reveal the valve but you're not done yet. On the side of the block opposite the hose is another cover. Remove this cover. Under it is a valve that you have to open like a water faucet for the charge valves to work.
In the (not too clear) picture, follow the hoses to the compressor, they hook to square blocks. On top of these blocks are acorn nuts. These are covers for the valves. Take them off. This will reveal the valve but you're not done yet. On the side of the block opposite the hose is another cover. Remove this cover. Under it is a valve that you have to open like a water faucet for the charge valves to work.
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From: Philadelphia
Appreciate the help. Still having some problems though.
I labeled my impression of what I'm looking at. I replaced both of the red circles with new 134a retrofits. I loosened both of the blue circles, started the car, maxed the A/C, then attached the 134a tank. My pressure went to 20PSI, then stopped and never moved again. Anyone see anything I'm doing obviously wrong?
I labeled my impression of what I'm looking at. I replaced both of the red circles with new 134a retrofits. I loosened both of the blue circles, started the car, maxed the A/C, then attached the 134a tank. My pressure went to 20PSI, then stopped and never moved again. Anyone see anything I'm doing obviously wrong?
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Joined: Apr 2009
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From: Stanley, VA
Yes. You've got the can of R134a hooked to the DISCHARGE side of the compressor. This is the high side. The other fitting is the suction side, this is the line you need to hook to.
The line you have labeled as high is actually the liquid line.
The line you have labeled as high is actually the liquid line.
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Joined: Apr 2009
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From: Stanley, VA
Strongly recomended. If he's converting to R134a from R12 he'll need to discharge the system, COMPLETELY flush the system, change the oil to an R134a compatible oil and pull a vacuum in the system then charge with R134a.
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From: Crestline, California
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Thanks for the clarification. Do I need to leave the valves I circled blue opened when charging, or am I supposed to close them?
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Hotshot
Joined: Apr 2009
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From: Stanley, VA
The valve on the discharge side stays closed. The valve on the suction side is the only one that should be opened.
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Joined: Sep 2003
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From: Northeast LA
Dude you need to go buy a lottery ticket, cause your lucky. That can could have exploded from the pressure connecting it to the high side like that.
You have the wrong fitting on there because high side and low side R134 fittings are different. You shouldn't have even been able to connect that can to the high side fitting.
Move that fitting to the other valve! and then follow all the other advice about flushing and pulling a vacuum on it then refill it only from the low side fitting. It'd probably be a good idea to replace your expansion valve at the inlet of the evaporator too with one that is for use with R134 too.
EDIT:
These would be a good idea to make sure you don't make that mistake again, plus you don't have to worry about opening and closing the valve on the end.
http://www.nostalgicairparts.com/air...a-port-591.php
Or these that hook inline with your hoses.
http://www.nostalgicairparts.com/air...e-port-596.php
http://www.nostalgicairparts.com/air...e-port-594.php
Another EDIT:
The oil you want to use is Ester oil. You need to drain the compressor and refill it with 10 oz of Ester Oil.
You have the wrong fitting on there because high side and low side R134 fittings are different. You shouldn't have even been able to connect that can to the high side fitting.
Move that fitting to the other valve! and then follow all the other advice about flushing and pulling a vacuum on it then refill it only from the low side fitting. It'd probably be a good idea to replace your expansion valve at the inlet of the evaporator too with one that is for use with R134 too.
EDIT:
These would be a good idea to make sure you don't make that mistake again, plus you don't have to worry about opening and closing the valve on the end.
http://www.nostalgicairparts.com/air...a-port-591.php
Or these that hook inline with your hoses.
http://www.nostalgicairparts.com/air...e-port-596.php
http://www.nostalgicairparts.com/air...e-port-594.php
Another EDIT:
The oil you want to use is Ester oil. You need to drain the compressor and refill it with 10 oz of Ester Oil.
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