Do you recharge the a/c on the high or low pressure side?

 

With the recharge cans that you buy at auto parts stores, you use the low side. Not to sure about the bigger shop machines.

 

I know the specs for the tl system are 17.6-19.4oz. Do these cans from the auto parts store measure in weight or psi? Any idea how much psi should be the max?

 

recharge on low side.....even the shop machines do it that way......let the compressor suck the r134a or freon(most pre 94 cars) in.

 

I dont want to add too much r134. I know the recharge cans come with a gauge. Just wondering what the limits for the TL are

 

The cans you buy measure psi. I don't know anything about recharging the system or how to translate the psi of my system to how full or not full it is.

Definitely interested in doing this, anyone want to make a diy garage?

 

If you're doing a complete refill, remember that you're also going to need a certain amount of oil. The oil in the recharge cans isn't enough for a complete refill.

 

when usually is it recommended to do a refill??????? ... i have never done a refill in any of my cars, but the ac seems to blow very cold

 

Then you don't need to recharge your system. You would recharge if you open up the system to replace something or if you have a leak.

 

The a/c system is not a maintenance item and needs no service, but if it's low on charge, there is a leak. Refilling by a can is hit or miss, as usually the system is filled by weight and/or using gauges to monitor the high and low side pressures as they do vary according to the air temperature and humidity. No oil needed if topping off the system.
Recharge on the low side and if it came with what they might call a gauge, guess you can use that to determine the amount needed. Just to give an example, 86 degrees, 70% humidity, low 45psi, high 190psi, but you'll need a manifold set to monitor.

Be careful with the gas, it can be dangerous.

 

I bought the refill can from walmart for 23 bucks. Hooked up the psi gauge that came with it and it read 37psi (with the engine running and a/c on max for 3 minutes). The bottle says for 90* outside, psi should be between 45-55 psi. I hooked up the can and started adding some r134a slowly. The psi on the gauge would move up when adding the r134 but went back down to 37 when I stopped adding it. I added about a 1/2 can and drove home

Once home I hooked up the gauge again and this time it read 35psi LOL. It wasnt leaking when I was adding it.

Did it work.?. I do know the a/c feels much colder now. I wasnt having any a/c problems prior today but I would notice from time to time that the compressor would take a few times to try and turn over when first turning the a/c on.

 

^have you inspected your clutch?

 

^I havent gotten that far yet. I was told that a compressor trying to turn over but cant is a sign of low r134. I figured I would try this first and take it from there

 

if the system is low the compressor will cycle on and off or will not engage at all depending upon how it is set up. if you put too much in the compressor will cut in and out due to hig pressure switch....

 

Using professional gauges (high and low gauge set) to properly fill an ac system requires experience to interpret what the gauges are telling you. Using a "freebie" single gauge to determine if the system is filled to specifications would be nearly impossible in my opinion.

In the "environmentally correct" days that we live in now, I am not allowed to recommend the following. The following is just me sharing how I did things "back in the day" before "Being Green" was that important.

The way I would do it, back in the dark ages, is to completely release all of the freon from the car. Then, I would refill the system using the amount of freon as stated by the specified capacity. Worked every time. And, of course freon was cheaper back then too.

 

If one does it this way the system needs to be evacuated before filling as this will remove air/moisture and air is non-condensable.

 

How would air and moisture enter into the system by bleeding out the freon thru the Schrader valve? I do not mean by removing the Schrader valve core. I mean by just pushing it in until the pressure was mostly gone. Still has positive pressure so no moist air will enter into the system, right?

 

Good info Inacc and turbonut.

This is something honestly I would have a shop do unless you buy a professional set of guages and a manifold.

My AC was never that good or I should say it was average. I did not have a leak and it was just as good as new after a couple years which was average. I had a friend completely evacuate it and recharge it, overfilling by 1/10lb. He said any more and it will hurt performance.

One important point, he said just about every Honda comes undercharged or at the extreme low end of ok. Usually I wouldn't recommend "topping off" but if what he said is true, it may be a solution for those in hot climates.

What I noticed was the air got cold much quicker. With the car in the sun on a 105 degree day it would take nearly 15 minutes to get cold. With the refill it took a minute. Huge difference in the time it took to get cold. Where the large difference was noticed was obviously on a hot day and with the fan on high.

My memory isn't that good but it was putting out some crazy numbers on that 100 degree day. I want to say 33 degrees with the fan on high.

About the compressor not wanting to turn over.... I've heard that too much freon can cause liquid in the compressor making it freeze up but I've never seen it. Low freon or I should say low lube will obviously do it but usually the low pressure switch saves it. I doubt topping it off could affect this.

 

You might consider buying even a cheap manifold gauge set - they can be even $40-50 on ebay. If you get one, post a picture of the high (usually red) and low (usually blue) gauges and we can help you read/understand them. If you post pictures of the fittings, we can also help you figure out how to attach them right.

If you really want the system to perform, make sure that the pressures are good at operating RPM. With a set of manifold gauges you can usually get under 40 degrees (90 degree day) both a idle and cruising. This is probably what the extra 1.6 ounces did above.

As long as you leave some positive pressure, most air will not be able to enter. If you go until there is no more pressure, then air can enter from venturi from the last bit of gas moving from high to low. Keep in mind that every time that you work on these things, some small amount of air and moisture gets in. There is always ambient air in the hoses, around the valves, etc. It is minuscule, but eventually will be too much for the dryer to keep up with if you jack with it a lot. After 3 or 4 can refills, then you are best to find/fix the leak, evac and recharge.

 

Thank you JDA. I was unaware that such a minuscule amount of air and moisture would impact the system. Thanks for the info.

 

I actually learned something from reading this thread

 

i did mines and it isent as cold as it was before. i was told that if you over fill ac components it will not produce as much or should i say th necessary amount of ahhhhhhh that is needed. long story short i drained and refilled and it oh so fresh lol.

 

I don't think that a single minuscule amount will hurt anything... just many minuscule amounts will add up over time. This is why even small leaks, while coolant is cheap, need to be fixed and the system closed again without ambient air and moisture. The dryer will get the moisture out for a while, but nitrogen gas, oxygen and the other junk in our air is not as good as refrigerant. In the end, the dryer will only do so much.

More low side pressure (more refrigerant) means warmer temps. This is likely why Honda fills the system with as little refrigerant as possible. When the compressor starts to turn faster, the pressure builds and the evap temp goes up. This is why you want fill the system with just enough refrigerant as necessary to keep the coil temp over freezing (36-38 degrees is good) when at idle... because when you start to drive and turn that compressor faster, that coil temp will go up to 40-44 or higher. I used to know about the max pressure drop and all of this like the back of my hand thanks to 3 thermo classes, but like most of what I learned in college I have forgotten most of it.

If you have too little of refrigerant, the coil will freeze. The low pressure switch will usually prevent this in a car, but it can happen. It happens a lot in older systems or in home AC systems.

 

One last thing.

When you add refrigerant on the low side, be sure and keep the can tipped up. You want gas to enter the system, not liquid. Tipping the can over is called "slugging" and it is letting the liquid enter the system. The issue is that these compressors are made to compress gas and not liquid. It might not hurt a time or two to slug in some liquid, but if the compressor is already worn or close to wearing out, it will wear it out further. You can also overfill faster by slugging. Lots of people do it, it just isn't as good.

 

^ don't you have to tip the can on some kits to get the pag oil in the system?