AC evaporator and low side line freezes up all the way to compressor,stops cooling.any ideas?

Sounds like a bad expansion valve or the system is overcharged.

 

Or... there is some residual moisture in the system that is icing the expansion valve, eventually blocking it. That should then melt and things will flow again, only to repeat.

 

The compressor does not cycle on/off but is a variable speed unit slowing as duty requires. You say you recharged the system but you do not say you evacuated it first, can you confirm that you did this?

 

1# question did it have the ice up problem before you change the evap ?.
2# in over 20+ of telling shops and people to use oe denso parts, I have never had a defective one or seen one, it is what someone has done or did not do that caused the problem.
3# Yes there is a point where the compressor will cycle off for a time, most of the time the rpm's will just be varied up and down. it depends on out side conditions and , sun radiant heat load, removed all the heat load (BTU's) from the interior mass, IE, dash, seats, duct tubes, glass, ect.
4# did you use your refrigerant identifier to make sure some how air did not get into the system this in some situations cause ice up.
5# did you replace the dryer sock, this must always be done when you open the system to the atmosphere. ? did you after recovering the refrigerant open the line and hear of feel a sucking sound from the system being in vacuum and the lines are cold, the rush of moist air into a a/c system is a vary bad thing, the water will condense out of the air right into the ester oil!
6# could you have not exactly put back the sensor in the same location?.
7# I would recommend calibration of your scale on your HVAC machine. this should be done several times a year, and they can read the 1lb or kg but actually but in 1.1 or 1.2 more or less?.

you can go to my photo album I have a little info about a/c for the Prius there on common mistakes.

 

Confirm that you have sufficient air-flow thru the coil. Since it is new, I will assume that it is clean (?).

 

Any time the system is opened and exposed to air for a period of time, you must change the drier. I'd also suspect that the sensor (thermister?) might not be located properly because it's job is to prevent freezing up of the coils. Your running the fan on low and the temperature setting on low also exacerbates the problem. Don't know what the humidity level is where you are but when I was in Florida a month ago it was in the 90%s.

 

If you want to properly work on electric a/c compressor cars using ester oil, and want them to last the life of the car? 28-29 in of vacuum is way not even close to being good. times are changing you must have a micron gauge and make sure you pull down to 700 to 500 microns would be better, the lower the better. and you can really tell if you have moisture in the system. There is also a moisture indicator you can attach inline that will tell you vary fast if the refrigerant and oil are saturated with water. It has always been this way even before cars first used electric compressor they have been used in commercial and residential for more then 40+ years. all the problems have been worked out, it's just automotive tech are not to bright and lack education. I repair and diagnosis messed up Pruis a/c systems week after week never ending all caused by sometimes well intending tech's but just lack proper training and education. Look in my photo album at tools to learn more about what is a micron gauge and a good set of gauges are.

 

The gauges made by Fieildpice and TESTO both have built in micron gauge, but I feel the one by Fiealedpice are easier for automotive tech to use and understand and cost about $300 less then the TESTO gauge. The Fieldpice model is SMAN3. You will also need to get a set of hoses, do not get a set of cheap china made hoses, I know it's tempting at $27 to $35 for the cheap ones but they do not pull and hold a deep vacuum. Ones made by YellowJacket or JB or Better Built they will be about $75 for a set of 3 red, yellow, blue. The best high vacuum hoses you can get at TruTech Tools on the internet, the company name Apollo hoses are about $75 each, and do not get the hoses with the shut off built in to the hose, when the seal on the valve leakes you need to buy a new hose not just a valve. Buy the separate valves. trutechtools.com this is a good internet CO I buy my tools from for HVAC, and the owner make great how to videos. Go to youtube and watch all the videos from HVACRat on vacuum and all the differences in tools and more how to tell if you still have moisture in your system. Every thing in his videos is what my dad taught me and some of the same tools when before I was in high school over 30 years ago. When I went to high school auto shop, I taught the teacher about A/C things he never knew or heard of.

Good luck, your on your way to preforming better A/C service and less headaches for yourself and your customers.
Tom Lech , owner and tech of Lech Auto Air Conditioning

 

I do not see the connection between moisture in the system and the coil icing up. Icing issues are almost always related to low air flows or plugged drains. It could also be that the temperature controls are not working properly and the compressor is not shutting off.

 

Sorry I also was not referring to to the ice up of the coil, but just not pulling down a deep vacuum with a a/c system and 10 fold worse if it has ester oil and a electric compressor will shorten the life of the compressor. If there there is moisture in the system I see many time that intermittent plugging of the expansion valve with ice in side as it expands and flash cools at that point. A another things automotive techs do not know is that in the process of manufacturing evaporators and condensers when joining the headers to the tubes a acid flux is used some times a little too much. In a new system this is no problem most of the time, because there is no oxidizing air in the system and no moisture with the new refrigerant and oil so the left over acid is inactive.
If I wanted to intentionally and maliciously damage a customers a/c system so the acid content that loves to attack aluminum and break down the lacquer coating on the electric compressor winding's here is how techs all over not even knowing do it every day. #1: The tech recovers the refrigerant this quickly lower the pressure and it chills to below freezing low in the evaporator were the oil sits in the bottom, low in the condenser, on the bottom of the accumulator or receiver dryer were the oil puddles at the lowest point trying to hold the refrigerant in the oil under the surface tension of the oil. All the lines get cold below the ambient air temp dew point. #2: Now the tech needs to replace the broken malfunctioning part or switch or sensor, they remove the part and because the system is in a vacuum and all the lines are cool the rush of outside warm moist air enter as the air passes over all the cool metal inside surface of the lines and oil, it instantly condensates the water right of the air in big water droplets. Just like a cold glass of ice water on a hot summer day. ! NO VACUUM CAN REMOVE THIS AMOUNT OF WATER!!... and the dryer was never made to handle this quantity of moisture. The water H2O love both CFC R12 and HFC R134a refrigerant one of the C in CFC is chlorine, the chlorine attach to the H in the H2O and produce hydrochloric acid and the F in the CFC is fluorine that attaches to the H in H2O when combined form hydrofluoric acid. If that was not bad enough many techs "if you can call them that" do not vacuum or only vacuum for a few minutes and leave air O2 in the a/c system, the O in O2 is oxygen one of the greats oxidized of all times. You ever see steel rust, it's not the water that made it rust, you ever see aluminium get that white fluffy or flaky power. That is the brake down of the metal.
That's not all now its time for the oil. The refrigerant oil was never meant to have water in it, air O2 in it, acid of any form, PAG or ESTER and there many kinds of PAG and ESTER oils, chemistry classification or family "not all the same". Many cheap universal plant base ESTER oil "I said from plant oils"" break back down vary easy into their base components. They are often sold as automotive refrigerant ESTER oils, THEY SHOULD NOT BE!!! but there is no law against it, and it will work and it is vary easy and cheap to produce so it gets sold and nobody knows, almost nobody. The water+air O2+ hydrochloric acid or hydrofluoric acid attack the oil and brake it down not to mention the different additive packages the are specific for different compressor material used in construction and the different load and heat and pressure that they will operate at. Then there is the different friction surfaces, bearing or races or rubbing pads and plates need different additives. THERE IS NO UNIVERSAL OIL...!!!... If you think so then in your new Prius only use the cheap .79 cents 30 W engine oil found at some road side quickie stop eat and gas places end of conversation.
I left a lot out, did not even talk about oil viscosity and many other specifically additives that are not added to NON-OE refrigerant oils and the damage they cause when they break down from air and moisture in the a/c system. I just wanted to get this information out there for professional competent tech who are always striving to be better.

 

im tring to remove the high side ac refridge hose i cant seem to reach the rubber clamp under the inverter pump any help would be great thanks