Im a new user and would appreciate it if someone could help me understand what this cars ac system is telling me.
This is a 2005 ford focus that belongs to my girlfriend. It was owned by her and her dad and he's since passed so there's no
way she wants to part with the car. I just keep fixing everything that goes wrong with it. Its a money pit.
The compressor went south last year so I decided to do a wholesale change out of everything I could easily get to
other than the lines. I changed out the compressor / condenser / accumulator / RCD ( I don't know what the hell its called in a car. the restrictive device that goes inside the line, it was an orange one. this car does not have a TXV ) and all new seals anywhere I took anything apart that had seals.
This car has always had a slow leak that I've never been able to find with the sniffer. Ive tried under the dash and the vents, the schrader valves, all connections and anywhere else I could think of. The sniffer never went off. I did test the sniffer with refrigerant and it works.
Heres the crazy thing to me. I can pull it into 29in of vacuum and it holds overnight . Thats crazy considering that I know for a fact that there is a leak. Im thinking there is a leak somewhere on the high side while under operating pressure. At least twice a year I have to add refrigerant.
So this time I pulled it into a vacuum for an hour and then let it sit for 30 mins to make sure it didn't drop. It didn't so I dropped some UV dye in and weighed the charge at 26oz per the Ford spec. The problem is that I have no idea what changes in the accumulator / condenser / compressor may or may not have been made by the aftermarket supplier. The dropped charge did not seem to be enough.
According to the ambient T/P chart the car seems off on the published numbers. Thats not to say that those numbers are correct and are maybe just ball park numbers. I was an HVAC tech for 15 years but that was over 30 years ago in the days of ambient +30 for R22 systems. I know next to nothing about R134a auto systems. It just seems that the vent temp should be colder than it is. But maybe I'm wrong.
Here are my numbers that I came up with that netted me the lowest vent temp.
Ambient - 91.4
Humidity - 75%
AC control on max and blower on 3 of 4 with recirculate on.
24" fan on high blowing directly into the grill of the car
Car idling at 1000 RPM - Suction pressure 45 PSIG ----- High side 225 PSIG - vent temp with digital gauge and HVAC thermometer in vent - 63
Car idling at 1800-2000 RPM - Suction pressure 30 PSIG -----High side 260 PSIG - Vent temp in vent 58
At all times during this test, condensate was just pouring out of the drain and the accumulator was sweating.
Are these numbers correct or do you think I have a high side restriction somewhere ? That restrictive metering device is what I would think could present a restriction.
Any help would be appreciated.
Thanks
Heres the ambient T/P chart that I found online for R143a
Also I have no idea if you should be looking at your pressures at idle or at 1800-2000 RPM.
I have googled it and there seems to be no rock solid answer.
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