AC guys, help ??

[fastfredracing]

Never seen this before . New ac compressor, condensor, evap core, expansion valve, and dessicant. System flushed, no clogs found. Pulled vacuum for a long time.
Started to fill system as normal, but as soon as the compressor cycles on, both the high, and the low side pressures decrease , equally .
At near full charge, both high and low are going almost down to 35.. Not an ac expert, but have been at this for a long time and never have I seen anything behave like this .
Did I get a bum compressor, or expansion valve ?
Honda CRV. The old comperssor ate istself and sent metal through everything . It had a full charge still when it came in.
Any ideas??

[908/930]

I am not an expert at AC, what temperature are you getting on your condenser? What is the system pressure when not running? Any chance of blockage near condenser?

[bob deluke]

I suspect a restriction somewhere Fred. When both pressures drop, it usually indicates a restriction someplace. You said the old compressor failed, sending metal through the system. It wouldn’t take much to plug the tiny orifice in the txv, causing a drop in pressure. Some metal filings could have escaped the flush and found their way back into the low side back to the txv. I believe you said you installed a drier as well. On the other hand, you could have a bum compressor, although I doubt it.

[Jeff Hail]

Originally Posted by fastfredracing

Never seen this before . New ac compressor, condensor, evap core, expansion valve, and dessicant. System flushed, no clogs found. Pulled vacuum for a long time.
Started to fill system as normal, but as soon as the compressor cycles on, both the high, and the low side pressures decrease , equally .
At near full charge, both high and low are going almost down to 35.. Not an ac expert, but have been at this for a long time and never have I seen anything behave like this .
Did I get a bum compressor, or expansion valve ?
Honda CRV. The old comperssor ate istself and sent metal through everything . It had a full charge still when it came in.
Any ideas??

Check the high pressure lines (skinny ones) leading to the bottom of the condensor. If they are cold and getting frost or dripping water drops stop, Evacuate the system and crack the lines and see if any debris is plugging them up. Next would E/V is plugged. Hondas do not have orifice tubes so dont knock yourself out trying to find it.

[wswartzwel]

Did you replace the little tube shaped filter screen?

[Jeff Hail]

Originally Posted by wswartzwel

Did you replace the little tube shaped filter screen?

Honda's do not have an orifice tube. They should though.

[asphaltgambler]

My opinion Fred, from your post; both sides are dropping which is contrary to a restriction. First let's separate the high side / suction side. The suction side drops to @35 psi when compressor is engaged. Depending on vehicle / temp / humidity, that's about optimal so that side is working correctly.

The high side is another story. If there is a restriction the high side psi would skyrocket and the suction side go to zero or possibly pull a vacuum. Your problem is the high side is not developing pressure. Whatever device ( expansion valve or similar) is holding off high pressure is stuck open, you would still see elevated high side pressure from static. My experience is you have a reed valve, swash plate stuck in 'neutral' position or other internal mechanical problem with the compressor.

[billybek]

Are you checking high side pressure at the compressor or on the liquid line supplying the expansion valve?

[GH85Carrera]

You may well have a defective compressor as well.

[fastfredracing]

It was in fact a bad compressor .. Right out of the box, Nothing like doing a job twice !!

[Arizona_928]

Originally Posted by fastfredracing

It was in fact a bad compressor .. Right out of the box, Nothing like doing a job twice !!

Brand?

[fastfredracing]

Carquest .

[asphaltgambler]

Y'all stick with me...