Trying to fill A/C system; blows hot air and high side has low pressure

[WHO1DMC]

I also had a problem with the new orifices tubes not fitting properly. I had to trim the nubs on the back side off or it would be to tight and crush the thing and of course not work.


Dave B.

[Bitsyncmaster]

I don't think I do -- I made sure to install it in the pipe where the original one was located. Of course, the only way to be sure is to remove the accumulator, I guess.

Before I do that, anything else I can look at?

-- Joe

If your not sure what orifice you installed you may want to pick up a new standard one. I'm not sure what the variable orifice would do if installed backwards. The standard one would work either way but the filter screen may not do it's job backwards. If no orifice was installed you would not see much high pressure.

[Ron]

Before I do that, anything else I can look at?

-- Joe

The pressures you see when you first turn it off are almost worthless...
1. You need to run it a little above idle and record the high and low side pressures when the compressor cycles OFF.

2. Go back to the diagram I posted and double check the routing. Also, compare the temps in the chart too*, IE, Red lines are hotter than Blue. E.G., immediately before the orifice tube should be hotter than after (downstream) of the orifice tube, etc.

My guess is you have the gauges correct now, but you may also have a line crossed *(because the Accumulator = Receiver Dryer in the diagram is too hot).

If once you get it where the accumulator is getting cool, it don't blow cold, you may have a door in the air box not acting correctly and/or water valve, as mentioned, or something else wrong as well.

[Ron]

If your not sure what orifice you installed you may want to pick up a new standard one. I'm not sure what the variable orifice would do if installed backwards. The standard one would work either way but the filter screen may not do it's job backwards. If no orifice was installed you would not see much high pressure.

+1
Imo, whatever orifice he has is working, so he needs to figure out why the accumulator is getting hot instead of cool before taking things apart....

[jangell]

If your not sure what orifice you installed you may want to pick up a new standard one. I'm not sure what the variable orifice would do if installed backwards. The standard one would work either way but the filter screen may not do it's job backwards. If no orifice was installed you would not see much high pressure.

I ordered a new tube and an accumulator for good measure. I got the original from DMC MW, so I assume it was standard, but they’re cheap so I ordered extras just in case.

— Joe

[jangell]

The pressures you see when you first turn it off are almost worthless...
1. You need to run it a little above idle and record the high and low side pressures when the compressor cycles OFF.

2. Go back to the diagram I posted and double check the routing. Also, compare the temps in the chart too*, IE, Red lines are hotter than Blue. E.G., immediately before the orifice tube should be hotter than after (downstream) of the orifice tube, etc.

My guess is you have the gauges correct now, but you may also have a line crossed *(because the Accumulator = Receiver Dryer in the diagram is too hot).

If once you get it where the accumulator is getting cool, it don't blow cold, you may have a door in the air box not acting correctly and/or water valve, as mentioned, or something else wrong as well.

I’ll try to jack up the car again tomorrow afternoon and see what lines are hot and what lines are cool when the condenser is running. Will be slightly disappointed if the A/C last ne fittings are the same size and easily swapped, because of how simply making the differ not sizes would avoid stupid people making stupid error like I did.

I should note that at no time was the condenser NOT running so far, so I don’t know what those pressures are, unless I disconnect the low pressure switch. Although the fact that this switch is causing the Compr sword to run continuously may itself be a clue.

I’ll need to check the water valve. I think it’s working, insomuch as the Vent mode temperatures (the one that just runs outside air through the cabin without the heater or A/C seem to match the outside air. I’d expect hot air if it wasn’t working, right?

Thanks!

— Joe

[Ron]

The water valve open would make it warmer than normal, but I wouldn't think anything like the heater running. But the doors/flaps might.

I'm assuming you meant "compressor" running all of the time. ...have to add that clue and think a minute...lol

[Ron]

If the compressor is not cycling, the evaporator could be froze over and it would not blow cold...,fwiw, same for overcharged a lot.

The switch should turn the compressor off when it is at the ~20psi seen in the pic.
Can you post a pick of "The pipe that runs across the front of [the accumulator]? post 17

Did you see in the diagram that the high side of the compressor goes to the condenser, not the low side as you posted?? posts 11-12
That would explain it all (especially if you were charging it when it was shut off???).

[David T]

Since you replaced everything you must now double-check EVERYTHING. Verify the output of the compressor goes to the driver's side hose and goes to the condenser coil. Follow the routing all through the system to make sure you have the flow correct. Make sure the fans are moving air through the radiator and the condenser coil and the cabin fan is moving air through the evap coil. When working on a car, to simulate it's moving, I put a box fan in front of it to help move the air around better. Helps to reduce the high side pressures. Since you were putting the refrigerant into the high side I doubt you got 30 oz in. Check that you have oil in the compressor with a dipstick. There is a sketch on the Sanden site to make one and the Workshop Manual tells you how to check it. When you vacuum the system you must get ALL of the air out before you put the -134 in.

[Ron]

+1
Except, I wouldn't rely on where the driver's side hose goes -- The Sanden SD709 comes with several back plates, it can be either way, some even have the suction in the center of the unit.

Whether the charge was being applied while the compressor was on or not is the key. If so, I'd suggest removing the hoses at the compressor and manually turn the compressor to identify the discharge port and confirm they are wrong.
...
Then evacuate it for an hour, recharge it while running, double check the gauge readings, and