R22 or R134a you can charge either way. I charge via liquid for larger volumes (lbs) and vapor for smaller volumes (oz). Of course when charging liquid you have to avoid slugging but that is true for the blends you have to charge liquid anyways.

 

Liquid charge with r22 when charging a repaired system or a dry ship. When adjusting charge in an operational system, vapor charge. I think it's sold by yellow jacket but there is a fitting you can buy that's supposed to allow liquid charging by basically metering the liquid to a lower pressure and not supposed to flood the compressor. I have one but only used it a few times, it resides in my scale case.

I have had a few discussions with guys who believe it's ok to charge liquid with 22 as long as you do it slowly and pay attention to the sound of the compressor.

 

Always liquid its faster

 

I agree with you that liquid its faster

I normally charge with liquid

 

I normally charge with liquid and meter with my manifold. Ain't nobody got time for vapor charging.

 

Ain't nobody got time for vapor charging.

+1

Ain't nobody got time for that.

 

Get away with what you can! Been there/ done that.!! But, my mechanical heart feels what it is i'm doing to that mechanical comp.
That "noise" from that "slugged" comp is the noise of you gambling. Again, beenthere/donethat.
Hot day, Hot conditions,Hot customer(female), I add vapor for 2-5 min, then I turn drum for liquid for 1 1/2 sec , vapor,liquid ,vapor and,,,,,,. If you really like this profession ,then FEEL w/ your mechanical heart, I think.

 

No need to keep flipping the bottle around. That just adds time to charging the system.

 

Liquid just don't be stupid about it.

 

Galt, are you saying to dump liquid into that vapor comp?
I re-read your post and I take it differently now.

 

Thanks guys...it's strange how subjective this issue is...some will say: "if you're ever going to liquid charge R22 do it very slowly to be sure to allow the liquid to vaporize before entering the compressor."
Wouldn't adding it "slow" defeat the purpose of doing it at all since you would only liquid charge to speed up the charge process?

 

Nope, even slow liquid is a lifetime faster then vapor. If you try and charge vapor you'll lose the cylinder pressure quickly and will have a bugger of a time trying to draw it in.

 

So you have a newly installed system that calls for 6 lbs of refrigerant in the compressor and say 2.5 lbs for the coil and line-set. Do you liquid charge say 6-7 lbs then vapor charge the difference?

 

Evacuated system, put refrigerant cylinder upright in sink and fill with hot water, be sure there's caps on tank to keep dry connection point. Wait several minutes to raise pressure then liquid charge into liquid line access with tank valve and high side on manifold open fully. Condensing unit disconnect off so compressor stays off till yer ready. Use digital scale watch refrigerant whistle into system - 5 lbs in a couple of minutes.

Topping up an operating system, front seat low side manifold gauge then just crack ever so slightly just so needle twitches, watch charging rate with digital scale, 1 oz per 30 seconds is ok but depends on size of compressor, bigger compressor can charge faster. Also as return suction pressure increases with charge, open low side gauge more to maintain charging rate.

 

On heat pumps I reckon the accumulator helps protect the compressor. Charge liquid, they do have a bullet metering device that one would use also, inline with the hose.


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Use a metering slow charge adaptor, place it on the tank and charge by liquid. The adaptor will prevent slugging. I think Imperial calls it "Kwik charge"

 

never had an issue with liquid charging liquid, just gotta keep an eye on the digital scale so you have some idea of how fast yer dumpin it in

 

When I first started I blew a compressor. Might have been something else going on though.

 

You don't need a "kwik Charge" adaptor. Your manifold/gauges are a metering device. I now utilize a YJ Titan so I can physically see it flashing but I successfully flashed from liquid to vapor for years with standard gauges.

 

If I do a repair where the entire charge is lost like a catastrophic leak or replacement dry ship condenser, I charge the liquid side with liquid watching the suction pressure come up to a "standing static charge" depending on outdoor / indoor temps. For instance on a mild day if I do a dry ship unit, after my micron level goes below 200 microns, I will connect the can upside down and send liquid in on the high side until both sides are for example 100 psig.
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Then I will valve off the sman. Start up the unit and watch the suction pressure throttling a little liquid in to keep the pressure up. If there is a suction accumulator you can be a little more liberal with the liquid.

As soon as I start showing 35 F superheat or if it's a txv 8 degrees of subcool. I slow way down and give it some time. Then adjust your charge according to system requirements whether it is subcooling for a txv system or superheat with a piston.

If the unit has a low pressure switch, be sure to keep the low pressure above the switch so it does not trip making you wait 5 min for a restart such as a heat pump. Remember scroll compressors should never be allowed to run below 20 psig according to the rules and ever unto a vacuum arcing the fusite pins.

 

Been charging liquid for over 12 years now and never had a problem. Just meter the liquid through your manifold. I usually open the low side valve on the manifold and watch the low side gauge I look for a 10 to 20 psi rise and no more. That way I know I'm not dumping to much in.

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One time I watched a tech working on a heat pump next door. He turned the can upside down connected to the true suction port which taps after the accumulator. He opened it wide open and got a phone call....the rest is history.

 

Since MOST compressors that we deal with are vapor cooled, that means that for any liquid to get into the cylinders, it needs to first pass over hot motor windings, I don't worry too much about liquid charging.

I'm normally looking for ways to get refrigerant into a system faster rather than worrying about damaging anything.

I'm pulling cores, pulling depressors, using large hoses... Come to think of it, it's almost like pulling a vacuum, just in reverse.

 

Charging R22...bottle always upright vapor charging or upside down liquid cha...



Thank you jp, when compressors runs low it runs very hot.

With a small amount of common since it would be damn near impossible to slug an compressor.

 

Adding mj-x oil your bleeding over high to suction for 3 minutes. I open almost fully. Compressor gets a little loud (not much). Its starved and hot anyways.

 

Air Cooled machine; Liquid charge to name plate charge after repairs and machine off

Water cooled machine, Liquid charge to name plate charge after repairs and machine off only if cooling water is flowing or if cooling water has been drained and blown out to prevent freezing.

Machine running. Most of the time l liquid charge until I get to within 1 or 2 pounds of my target pressures. Then it depends on how close I am to the subcooling & super heat values.

This provides the least amount of pressure and temperature drop in the refrigerant bottle. The hoses, the manifold, the schrader valve on the system are all restrictions and help minimize the potential for slugging liquid. Watch the frost line and compressor sound. When you hear the tinkle, tinkle, tinkle on a recip compressor it many times is too late. Over time you will get a feel for how fast to feed liquid. Especially if you have replace a compressor because you were not paying attention

Good Luck

 

I have started to charge exclusively into the liquid side. Shut the unit off and use my recovery machine to "recover" the liquid refrigerant from the bottle and push it into the liquid line. This only works when I am weighing in the charge, but almost all the machines I work on have good nameplate data and so I weigh it in. Actually, when I am using recovered refrigerant I can go even faster by using the recovery machine and two tanks.

Pull liquid from one tank and push it into the other while the liquid port is connected to the system. It pressurizes the 2nd tank and pushes all the liquid out while pulling liquid from the first tank. I emptied 60 pounds of R-22 in 15 minutes last week using this method. It has the added benefit of clearing out the 1st tank down to -10"mmhg if you let it run long enough.

 

Why not just close liquid line service valve and pump down and add liquid from virgin refrigerant bottle to get a close charge.

 

I forgot this is the residential forum. Are you able to get the whole charge to pull into the unit just from a vacuum?

I will if I can but I'm pulling the charge and weighing it on two 100 ton intellipak circuits today and both have a 100 lb R-22 capacity. When I recharge them, I'll be able to get maybe 50 lbs virgin into the liquid side before the pressures climb too much to get anymore in that way. I also have to put the 60 or so pounds I've recovered on each circuit back in (major leaks on the unit.) I used to pull the remaining 60 lbs slowly through the suction side, even as a liquid this takes forever. Now I push it in like my last post and in goes really fast.

 

Wait, I just reread your post. If you pump down the unit are you pulling liquid refrigerant into the suction side? Aren't you worried about slugging the compressor when it starts up again?

 

Virgin refrigerant liquid enters the liquid line , pulled through the TXV and then enters compressor and is stored in the cond. coil.

 

I've never tried that. I will next one I charge.

 

I typically dump liquid into any port I have available from a full vacuum. When it stops flowing or I reach the charge, I stop. Put away the non needed tools, make sure everything else is ready to run, kind of figure out the bill, basically give it 10 - 20 minutes for the system to go back to a normal shutdown condition, before I start the machine. Never damaged a compressor.

When I worked in the factory we would charge from a full vacuum at the compressor (the little brazed closed nub) and have the machine running within 5 or 10 minutes. I've seen thousands of package machines done this way no compressor problems