New 7h15 Sanden compressor defective?

[Andrews Branco]

Hi, I have a Peugeot 405 1995, I recently did a complete check on the air conditioning, I cleaned the system completely, changed the expansion valve, filter dryer, compressor, and put 180cc in the oil.

the system is working, but with low efficiency, on hot days (91F) the low pressure is around 45 - 50 and the high pressure is around 180 - 200, when I accelerate to 2000 rpm the high pressure rises to 250 and the low speed drops a little to 40, however the air efficiency is not good, it only cools well when I'm accelerating the car, at idle it doesn't cool well, I tested the compressor by turning off the fan it reaches 350 psi however it takes some time.
One thing that makes me curious is the compressor working cold, the return line condenses and the compressor reaches (50F).
I believe it is not a defect in the expansion valve because the system takes a while to equalize pressures when turned off.
Remembering that this compressor is fixed.

unobstructed condenser and evaporator.

What are the chances of a new sandem compressor being defective?

[Tim]

Hi, I have a Peugeot 405 1995, I recently did a complete check on the air conditioning, I cleaned the system completely, changed the expansion valve, filter dryer, compressor, and put 180cc in the oil.

the low pressure is around 45 - 50 and the high pressure is around 180 - 200,

What are the chances of a new sandem compressor being defective?

I'd be looking at other areas, as the compressor seems to be working. What refrigerant are you using?

[tbirdtbird]

"low pressure is around 45 - 50 and the high pressure is around 180 - 200"
I assume these readings were taken at idle. Idle pressures have little meaning, as the comp does very little work at idle. No mobile AC does well at idle ie in traffic and stop lites, etc.
The set of pressures at 2000 RPM is what tells the story. We usually ask for pressures at 1800 RPM so you are right there. Those numbers are indicative of a fully functioning compressor.
You said you 'cleaned the system completely'. Does that mean you flushed the lines and all? If so, what type of flush did you use? There may still be flushing chemicals in the system which will impair the operation of the system. How did you pull a vacuum? Electric pump or air operated pump? and how low a vacuum did you pull? How did you determine how much refrigerant to install?
What triggered you to do all this work? How many miles on the car? If the compressor died, then shrapnel from comp is now in the condenser and will limit performance. When you change a grenaded comp you must also change the condenser and the TXV. You did change the TXV but the debris from the condenser is working its way to the TXV impairing that function. A condenser cannot be flushed.
If you are able to respond to all these points we can further assist

[tbirdtbird]

You may also have what we call re-heating. Your blend doors may be acting up and allowing heated air from the heater core to over mix into the cooled air. The hot air always wins.

[Andrews Branco]

Hi, I have a Peugeot 405 1995, I recently did a complete check on the air conditioning, I cleaned the system completely, changed the expansion valve, filter dryer, compressor, and put 180cc in the oil.

the low pressure is around 45 - 50 and the high pressure is around 180 - 200,

What are the chances of a new sandem compressor being defective?

I'd be looking at other areas, as the compressor seems to be working. What refrigerant are you using?

I'm using r137a. After some tests I discovered that pressure switch is not activating the fan at high speed, I believe that for this reason the car was losing a lot of efficiency in traffic. I'm waiting for the new part to test.

[Andrews Branco]

"low pressure is around 45 - 50 and the high pressure is around 180 - 200"
I assume these readings were taken at idle. Idle pressures have little meaning, as the comp does very little work at idle. No mobile AC does well at idle ie in traffic and stop lites, etc.
The set of pressures at 2000 RPM is what tells the story. We usually ask for pressures at 1800 RPM so you are right there. Those numbers are indicative of a fully functioning compressor.
You said you 'cleaned the system completely'. Does that mean you flushed the lines and all? If so, what type of flush did you use? There may still be flushing chemicals in the system which will impair the operation of the system. How did you pull a vacuum? Electric pump or air operated pump? and how low a vacuum did you pull? How did you determine how much refrigerant to install?
What triggered you to do all this work? How many miles on the car? If the compressor died, then shrapnel from comp is now in the condenser and will limit performance. When you change a grenaded comp you must also change the condenser and the TXV. You did change the TXV but the debris from the condenser is working its way to the TXV impairing that function. A condenser cannot be flushed.
If you are able to respond to all these points we can further assist

First of all, thank you very much for your answer, and sorry for my bad English.

Let's answer in parts:

The car has 40000 milles.

What motivated me to change the compressor is that moisture entered my system and some parts rusted, the compressor blades were one of them. My compressor wasn't damaged, there's no shrapnel in the system, just rust and a lot of oil.

I discovered that the pressure switch is not activating the High fan speed, I am waiting for the new part and will post the results.

I know it's not ideal to clean the condenser but as the compressor didn't break, I thought it might be worth it, besides it being difficult to find a new one for this car. It was very clean and measuring the temperatures, at the entrance 130 degrees and at the exit about 105.

The amount of fluid was 650g according to the manual.

The flush I used a product specifically for this, which is very volatile, and after cleaning I vacuumed, filled with N2 and then vacuumed again, I repeated this process about 5 times ,I think it very difficult to have any residue of product left in the system.

I use a Eletric vacum pump 5CFM double stage.

I understand that the compressor does not have its best efficiency at idle (800 rpm), however here in Brazil this compressor (7h15 150cc) is used in tractors and vans, and works perfectly, even at idle, because it would not work well in a car small?

Now what intrigues me most is the compressor is cold (50 degrees) and the drain pipe is not very hot, and it is possible to put it by hand. what causes this? it's normal?

[Andrews Branco]

You may also have what we call re-heating. Your blend doors may be acting up and allowing heated air from the heater core to over mix into the cooled air. The hot air always wins.

I did the test by removing the actuator and turning it manually, the valve is 100% in cold air.

[tbirdtbird]

"I discovered that the pressure switch is not activating the High fan speed"
This will definitely impair the system.

Sounds like your flushing method was quite acceptable.
When you say the refrigerant is 137a, do you mean to say 134a?

"Now what intrigues me most is the compressor is cold (50 degrees) and the drain pipe is not very hot, and it is possible to put it by hand."
Which 'drain pipe are you referring to? Do you mean the so-called hi-side pipe coming from the compressor? When the ambient is 50 degrees (I assume you mean 50 degrees F? or it is degrees C?
Do you mean you can grasp onto the hi-side pipe and it is not too hot to hold?

If you mean 50* C ambient, that is 122*F which is an *extremely* hot day
If you mean 50* F ambient, that is a very low temp and the compressor would be doing very little work.
Please clarify