All i use at work is PTR charts, and yes if you have the manufacturers weight of refrigerant required that is the best. The chart you listed is not even close. If you have a R134a system pushing 300 psi, you compressor will not last week. 300+ psi is even too high for R22 and I don't even like to get R404a.

For using a PTR chart for the high side take ambient temp and add 25-30 degrees, convert that temp to a pressure and that is where your high side pressure should be.

On the low side your vent outlet temp should be about 20 degress above your suction pressure converted to a temp on a PTR chart. For air conditioning you do not want you suction prressure PTR conversion to be below freezing as this can allow ice build up on your evaporator, and air conditioning systems do not usually have a defrost system.

Now I have never serviced a system in the 110 degree arizona heat but I have done plenty of systems in 110 degree Kitchens and navy galleys.

matt

 

I work with 410 and home air conditioners... Although I have both epa cards. All the PTR charts I've seen have listed those numbers.

I did find on Vintage air's site a rule of thumb for the high side - 2x ambient + 15-20%.

So, for 80° ambient that would be 160+15-20% or about 184-192psi. The chart I posted says 175-210psi. At 100° it would be 230-240psi whereas the chart I posted shows over 300... The high pressure cutout's that I've seen are in the 400-450psi range, so who knows... The fan switches come on around 220psi.

I wonder if that chart is in some way trying to account for underhood temps for people who are measuring ambient via local thermometer vs an actual thermometer at the condenser.

In any case you need about 24-25psi low side for the compressor to work.

The outlet of the evaporator should be 34-46°F.

I've also learned that overcharging can cause a noisy compressor....

 

Well I pulled the orifice tube and it was completely covered in black goop. I came across that this is a sign of a failed compressor. This would explain the remanufactured one that's in there now.

I think I want to clean the entire system as well as possible and replace the expansion valve also.

Now, what is the best way to clean the system, short of removing the evaporator and where is the expansion valve. How do you use AC flush? Should I get it flushed out in a shop for best results, or the 'flush in a can" works OK.

I also found out on www.alldatadiy.com that the refrigerant capacity for this truck is 44. I'm assuming that's 44 oz.


Thanks again.

 

The orifice tube is the expansion device, It does not have an expansion valve just the orifice tube.

A couple of cans of the flush from the auto store has always done well for me in the past.

While you are in there again since things were covered in black "goop" It would also be a wise idea to replace the filter drier/ accumulator.

Matt

 

I just put in a new drier before charging it for the first time. Is there a way to clean it out, or should I get a new one. I guess what ever gunk was in the system is now in the drier.

Thanks for your help.

 

Man that is a hard one to call. Safe money says replace it again after you do the flush, but then you have never really had the system running. I would say pull out and run a swap on the inlet tubing(coming from the evap to drier) and if it is clean reuse it, if you find the black junk then replace it again

Matt

 

What if I disconnect it and clean it so no other goop from the rest of the system gets into it.

Is this possible.

Guess I'd back flush it. Is brake cleaner OK for this?

Thanks for sticking with me through this.

 

As far as flushing the system I would stick with using the flush designed for this purpose. I do not know how brake clean residue would react with refrigerant. Pull the dehydrator out of the system before you run the flush through it.

Matt

 

When the FS10 compressor fails it causes what is know as Black Death.
Click on the link below

Polar Bear, Inc.

 

thanks for your help

 

OK,
will do.
I appreciate your help!!!!!!!!!!!!!!!!!

Wish I could buy you a cold one.

Thanks <!-- / message -->