Air conditioner blowing warm air

I was just making observations what I see on my gauges versus what I see on cars with a belt driven non-inverter electric compressor and quick ways to tell what's up yes if you have 45 lb on your gauges you'll have 45 lb on the high and the low side I've noticed that in our cars when everything is pretty much correct if you hook up your gauges whether there's a $400 type or the one on top of the AC pro can at rest car off just sitting there you got about 85 to 95 lb it looks like standing at rest the minute you start the car and push the button if you're looking at the gauges you see the low side start to suck down into the 20 range and the high side start to go up into the 200 range on a 90 some odd degree day here in North Carolina the fat tube gets cold the skinny tube is hot bringing the heat out and that's about the boring end of it. Sorry if this caused any confusion I also install my own mini splits run line sets expand line sets solder them up all of that never had a problem yet .oh well

 

Standing at rest, you get whatever pressure is in the R134a saturation pressure chart for whatever the current temperature is.

So if you're seeing 85 lb, you know it's 79 ℉. If you're seeing 95 lb, the temp is about 85 ℉. If you're seeing 45 lb, the temp is around 50 ℉. So it's a thermometer. It's telling you what the temperature is. (In the engine compartment and cabin, which might not match what the weathercaster said on TV.)

What it's not telling you is whether the amount of refrigerant in the system is correct. As Tom Lech aptly stated already, if there is any liquid refrigerant in there at all, whether it's a drop or a pound or two pounds, you will see the same known saturation pressures at the same temperatures. (He said a drop or "100 pounds", but I'm pretty sure our systems aren't big enough to get 100 pounds in. ).

 

Ok sounds great I'm not equating gauge pressures with amounts or weights. It's just what I see on AC in car I see working . 85 to 94 PSI at rest will equal 30 and 240 ish respective gauges and cold fat tube ...hot skinny tube . Even my house AC has no SIDES until compressor is running .

 

Once again, this only tells you the temperature of the car at rest. You see 85 psi at a temperature of 79 ℉, you see 94 psi at a temperature around 84½ ℉, and for any other temperature, you can see what the pressure will be in the chart.

You'll see those same pressures at those same temperatures whenever there is any amount of liquid refrigerant in the system at all, from way undercharged all the way up to way overcharged.

 

Just a quick question as it relates to the prius A/C system. Does the compressor run off of the high voltage battery?

 

Yes, indirectly. In a Gen 2, you'll see three orange wires (orange, high voltage, caution) connecting the compressor to the inverter box above the transmission.

The inverter has a section that takes the high-voltage DC from the traction battery and drive train, and inverts it into a three-phase AC supply that it sends to the compressor.

(You didn't ask about Gen 3, but in case any of those folks are reading, Gen 3's a little different: the inverter to three-phase is in the compressor itself, so that one only has two orange wires, bringing it DC.)

(You also didn't ask about Gen 1, but that one had a conventional compressor driven by a belt from the engine. So a Gen 1 had to start/stop the engine really often to maintain cooling, if you were sitting parked with A/C on, and that was annoying.)

 

Wow. Those are OBD1 engine computer flash codes- on a list that says it's for Toyotas that are older than 1996. So what you posted is correct - if you happen to have a check engine light on a 92 Camry (for example). These code definitions are not correct for any Toyota 1996 or newer- esp the HVAC system on a Prius.

Posted via the PriusChat mobile app.

 

Sounds great but forget the temperature of the day we'll say it's summer because I'm checking my air conditioner I go out on a 88° day at the beginning of Summer and I just check quickly the pressure in my air conditioning system at rest and it says generally between 84 and what looks like 95 PSI at rest the minute I turn on the air conditioner with the car running or not that 85 PSI becomes a high and a low side and then my low side never goes over 30 and will suck down to almost 15 and my high side goes up to about I don't know 240 I think and by these numbers after the compressor is running I know generally that I'm in reasonably good shape because those are the numbers that I see on a good running setup whether it's empty or not I have no idea I think if it's empty it will suck that low side down to zero and then it will break prime or something in the high side will fall and you'll have no cold air something like that I just use that 85 to 95 to see that there's something in the system and when I turn that on that 8595 on the low side is going to pull down to 30 immediately and the high side is going to go up to where it needs to be and the fat lines going to be cold and then I'm done sight glass is great so I'm leaving it

 

I dont have any AC issues but had previously just read and watched a lot of info on prius and the one thing that came up over and over was charging them by weight of the refrigerant and not pressures. These were all trouble shooting docs and videos of systems with problems

 

Yes, there is a difference between what the operating pressures tell you, and what the resting pressure tells you.

Yes, that 85 to 95 will tell you "there's something in the system". Assuming it's summer and the temperature is between 79 and 85 ℉, you will see 85 to 95 psi if there is any liquid refrigerant in the system at all, whether it is one drop, or a huge overcharge.

What the pressures change to once the compressor is running will tell you more than that. On the other hand, because it is a variable-speed compressor, and the system has a TXV, they might still not tell you as much as in an older, simple system with one compressor speed and an orifice.

 

I will try that next time I'm gassing up an empty or starting up a new system as I apply gas and see how many cans it takes me to get to that 85 to 95 PSI I think it was about two cans until that pressure would show on either side of the system given there's no side when it's off but a drop wouldn't have pushed me to 95 PSI I don't think or 85 whatever I think I had about two cans in the system one can I don't know gave me maybe 35 something like that I can't honestly remember but it was seemingly incremental to me I didn't notice a drop go in or half the can go in and I was showing a hundred pounds off sitting there I had at least two cans in the system and that's getting pretty close or 1.6 cans or something like that

 

It’s a choice it’s the difference between somebody who knows how to do it right 100% of the time and fully delivering the correct SuperHeat in oil delivery back to the compressor

or the difference between somebody who just guesses and gets it halfass right so it delivers a system that just turns on and delivers cooling to the customer
not taking in consideration that they could be under charge in overcharge and starving the compressor causing it to run in an operation where it’s overheating but still working or lack of lubricant or getting floodback with excessive Refrigerant but still operating and delivering cold temperatures out the dash

at the same time without even a clue that it also causes the compressor to draw more watts of power to spin longer durations when it is short on refrigerant on hotter days draining down the high-voltage battery cycling it more often shortening its life over its lifetime duration due to the way the individual improperly recharged the refrigerant level.

Whether it’s overcharged or undercharged both cause a higher demand on the high voltage battery with more power drawn from the electric compressor

The difference between a professional and the difference between guessing and whatever sticks on the wall and works but slowly causes damage to the compressor when it’s not correct

both methods get the system up and running one of them just occasionally causes damage

so it’s anybody’s personal choice which one they wanna choose on their method of checking and recharging systems

 

You will find it'll be as many cans as it takes for any of the refrigerant in the system to be liquid.

Once there is any amount of liquid refrigerant in there, you will find the resting pressure follows the saturation chart and the temperature.

 

You are 100% correct I cannot even count how many thousands of times and I literally mean thousands of cars that I have recovered 2 ounces 3 ounces or 4 ounces of refrigerant and and it was very easy for the static standing pressure to be 80 psi 90 psi even 100 psi on a hot day and only have 2 to 3 ounces of refrigerant in the system.

standing stagnant pressure means absolutely nothing

 

Don't our systems only hold like 1.4 lb I thought that's what my Corolla had in it basically That's what the sticker says under the hood

 

1.4 lb would be around 22.4 ounces.

 

So pulling three or four pounds out of one of these things I don't even see how the thing would be running I noticed that if you go over on the gas even a little bit that inverter compressor starts struggling immediately you can make it shut off or lock up whatever you want to call it bleed off some gas and it'll work The electric is a lot more sensitive obviously it doesn't have a whopping belt running around it connected to the crankshaft

 

Did you notice that post #35 refers to ounces?

Three or four ounces is a fraction of a pound.

 

yes they do hold somewhere anywhere between a pound and a little bit more on small compact cars

But many leak and by the time they come in to the shop sometimes they only have a few ounces of refrigerant left inside of them.

And when they have 1 ounce 2 ounce or even if it was 10 pounds when the liquid refrigerant is 70°F it will be roughly 70 psi it does not matter how much refrigerant is in the system at static pressure.

And this is the reason why they came into the shop because they don’t have 1 pound or 1 1/2 pounds of refrigerant in their vehicle.

And on some make model vehicles with variable displacement compressors and variable speed condensing fans that are all controlled by the computer you could have 50% of the refrigerant charge in the system and depending on the ambient conditions the low side pressure and high side pressure will be exactly the same as if you had 100% of the refrigerant charge inside the system.

And that all depends on the manufactures algorithm that they have programmed using the sensors to adjust the compressors displacement and the fan speed to control the refrigerant pressures to stay exactly where they want them. ( not dependent on the refrigerant charge level)

You could kinda get a sense of this by experimenting yourself on an old-fashioned car that has fixed positions compressor displacement.

And you can completely control to a certain degree the high side and low side pressure even with a partial charge of refrigerant.
By controlling the fan pulsating it disconnecting it and watching the high side pressure and you become the switch that determines exactly at what pressure you allow the high side to raise two and then you can pulsate the fan electrically slowing down its speed to control the high side pressure to stay exactly where you want it whether you have 50% of the refrigerant charge or 100% of the refrigerant charge by controlling the air moving over the condenser.

And you can somewhat to a certain degree control the low side suction pressure at the same time by controlling the rpm of the engine that will control the rpm of the compressor because compressors are not efficient and do not give you your true correct reading at idle they were not designed to operate properly at idle

So you start playing with the engine rpm into it achieves the low side pressure that you want even though you do not have the correct refrigerant pressure and then you play with the fan pulsating it to slow down or raise the fan speed to give you the high side pressure.

And now you are basically mimicking somewhat similar to what the computer does with a variable displacement compressor and variable speed controlled condenser fans.

And depending on the ambient conditions of temperature and sunload I actually have videos that I have posted in the past of a Prius that is nearly 50% refrigerant charge at times having a clear cy glass putting out 39°F to 41°F out the dash but yet not have a full charge of refrigerant

On the other hand depending on the ambient conditions I have videos posted on Prius that have 100% refrigerant charge but yet have a cloudy bubbly sight glass even though the Toyota technical manual says it should be clear.

A lot of the stuff published by Toyota and other manufactures is old reprinted material. And a lot of it has been printed for Third World countries where the majority of people small independent shops do not have access to recovery recycle and recharge machines so they do not list a sticker under the hood with weight they give the bubble method and pressures in some countries I have conversations with these individuals who call me or text me over my YouTube channel disgusting what they have or don’t have in their particular country .

So in those situations all they care about is getting it kind of close within 100 yard goal post football field kind of area so long as it works

they’re not going after precise accuracy they’re not going after the highest efficiency they’re not going for best gas mileage or thinking about that their electric compressor might be drawing more amps of power because it’s slightly over or under charge that will Degra gate and shorten the life of the high-voltage battery just because they got it cold out the dash but not properly recharged.


Even if you give an eight-year-old child a hose in a can and teach him the basic principles he can squirt in enough refrigerant to get it coming out cold out the dash that’s no big feat it’s very simple.

It’s getting the system vacuumed down to where you actually can read the moisture removal and reduce the moisture content to its lowest point reduce the air content down to the micron level of contamination and then precisely filling it up where the compressor can run at its optimal most efficient level to provide the highest cooling to the dash for the passenger at the same time providing a nice cold mist of refrigerant oil back to the compressor lowering the load on the electrical windings extending their life and consuming the fewest amount of watts draining the high-voltage drive battery .

you would not believe how many customers that I’ve seen who have poor gas mileage on the Prius and the engine is constantly coming on attempting to recharge their high-voltage battery because somebody overcharged chess by two or 3 ounces the refrigerant on the AC system or exact same problem two or 3 ounces low on refrigerant charge both situation call excessive watts of power to be drawn causing the engine to constantly come on more often consuming gasoline to attempt to recharge the high-voltage battery because the person who recharge the system did not know what they were doing .

But they got cold air coming out of the dash and called that good