AC - Hot and cold same pressure

[tweak]

Hey all,

Any AC guys in the house?  I went and got some ac gauges from adult toys R us (Harbor freight) and with the compressor running, the hot side is the same psi at my cold side (40).  The compressor is running, but I assume, doing nothing.  New compressor time?

Thanks.

[Donthitme]

Are you going by the temperature chart?  It's going to read different depending on the ambient temps.

[tweak]

I understand the temperature thing, but shouldn't the low side be low (40s) and the high side be.... high?  (150+)  Not both 40?

[Donthitme]

When you filled the system did you open the low side or high side? or  both?   We could use more information on the steps you've taken to charge the system.  How much r134 have you put in it?

To answer your question, normally yes. High side normally has higher pressure.

[tweak]

When you filled the system did you open the low side or high side? or  both?   We could use more information on the steps you've taken to charge the system.

I didn't fill anything.  I just put the gauges on...   Low says 40, high says 40, compressor is running.  To maybe stop the confusion, the engine and AC is still in the firebird, I just want to drive it around in the heat, and trust you guys more than ls1tech.

[Donthitme]

When you filled the system did you open the low side or high side? or  both?   We could use more information on the steps you've taken to charge the system.

I didn't fill anything.  I just put the gauges on...   Low says 40, high says 40, compressor is running.

It's usually equal pressure when the compressor isn't running.  Verify that you compressor is kicking in, you may just have low Freon and the pressure switch isn't engaging the compressor.  Is the center of the compressor pulley spinning?  If it is running you most likely have a bad compressor.

[tweak]

Not sure if trolling now or just high, but I said the compressor is running multiple times. It's actually in your quote. lol

New compressor time, yay.

[Donthitme]

Not sure if trolling now or just high, but I said the compressor is running multiple times. It's actually in your quote. lol

New compressor time, yay.

Not trolling, people make mistakes.  Just wanted you to verify. 

[tweak]

   <3s    Thanks.

[halfspec]

Bryan is correct. It's a very common mistake for people to make. Hell, I even made it ~4 years ago and it fooled my brother 2 weeks ago. People see the belt spinning the compressor wheel and figure, hey the compressor is on, but they don't notice that the center isn't spinning. For the compressor to be running, EVERYTHING inside and out on the pulley / clutch assembly in front of the compressor MUST be turning. If its not you're either not getting 12v to the compressor or you're low on freon and the compressor is NOT "compressing"

What you're describing (equal pressures on the high and low side) is almost certainly a non-engaged compressor. Even a dead compressor can generate a little bit of a pressure differential in most cases.

Lane
 

[Donthitme]

Thanks Lane.

Look at the center closely.

[tweak]

Video of mine.

http://youtu.be/Lzr2MDXjDyw

[attach=1]

[Donthitme]

Yup it's shot 

[halfspec]

Yup. If your gauges are working properly I'd say the same. Sucks man.

Not only is your compressor trashed, but I expect you've got garbage spread throughout your entire AC system from the compressor breakdown. I would replace your drier/accumulator, condenser, expansion valve, and thoroughly flush your evaporator and lines.

Lane

[SSjon]

Yup. If your gauges are working properly I'd say the same. Sucks man.

Not only is your compressor trashed, but I expect you've got garbage spread throughout your entire AC system from the compressor breakdown. I would replace your drier/accumulator, condenser, expansion valve, and thoroughly flush your evaporator and lines.

Lane

^ most likely yes, I have never had gauges hooked up to a running failed compressor but it just seems odd that there is no pressure change at all. Almost like the orifice tube is missing...