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Member Post posted an update
May 30, 2025 (edited)
I’m working on a York YS Style E water cooled chiller. I can’t get it to go down past 170k microns. I have pressurized the chiller and found one decent size leak on the oil separator sight glass and a pressure transducer. I have made the repairs. I did use trace gas to find the leaks and also soap bubbles. I still can’t get the chiller down past 170k microns. I have leaked checked the entire chiller. I have checked pressure relief valves, drain barrels and have put my leak detector inside the ball valves that’s on top of the barrels to let air in when draining. I even have 2 vacuum pumps on it. The chiller was down for week or so, but would that cause the chiller to absorb so much moisture?
Member Post, Member Post and 4 others36 Comments-
when you say 170k microns do you mean 170,000? that’s only 23 inches in mercury of vacuum, almost as though your gauges are leaking or a valve is open to atmosphere. have you done a pressure hold test?
I have heard people saying you shouldn’t use two vacuum pumps in case one pulls through the other (I’m not advocating this thought but could be a possibility)
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@Vas yes, 170,000 microns. That is a huge leak. I pressurized it to 144 psi. I’m just letting it go through the low side. I have the service valve on the evaporator barrel wide open and even then the pressure on my high side gauge is going down very slow. So that tells me it’s not a leak. I would be able to hear it.
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@ronnie5 let us know how it works out man.
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What is the model number YS screw, YT or YK centrifugal?
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On the top of the Mickey Mouse ears of the compressor there is a tiny weep hole on most of the compressor. Test at that point and if you pick anything up there the seals in the end of the compressor need changed.
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@jselvage I was picking up a few hits around the compressor shaft but nothing I could confirm with soap bubbles. So I don’t think that’s it. This is crazy it’s the first time this has happened to me. It’s almost like if I was trying to pull a vacuum with 2 service valves wide open.
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when you recovered it was it short on gas? not being able to pull below 170K microns is a missive leak. You going from vacuum straight to chiller?
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@J.MC yes it was very low on charge. It takes 800 lbs and only recovered 240 lbs. It sounds like a massive leak, but I can’t believe I can’t find it. I have found 2 small leaks and repaired them. I have checked all around the chiller multiple times.
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Did you check your relief valves and around the discharge check valve
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@jselvage I have pressurized the chiller to 144 psi. The original leak was around the discharge flanged and repaired it. I did find a couple of pressure relief valves leaking but I have those capped off right now.
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Are the eductor lines steel? Maybe you have rusty, leaking lines under the insulation
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@jselvage I have insulation off the eductor lines and have found nothing.
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I can’t be much help then, my leaks have almost always been the end of the compressor or shaft seal.
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@jselvage These chillers have been notorious for leaks. It has O rings everywhere. I wouldn’t recommend changing the oil on these unless you really have to.
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Be sure to let us know how everything comes out
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Man I remember YS back in the day they would leak all the time LOL
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I personally don’t put much faith into pressure testing, I’m more concerned with the vacuum holding. I’ve had parts like the head of an old style RTAA EXV that will hold pressure but leak under a vacuum due to the construction of the electrical connection at the top. Off the top of my head, I can’t think of anything on the YS that could be doing the same thing.
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@jselvage I just can’t believe that something would be leaking that bad under a vacuum. If it was whatever it is would eventually give when putting under pressure then pulling back into a vacuum. I believe that the oil has some moisture in it or refrigerant.
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@jselvage Hey Jody< You work for EMCOR? i believe i see you at times in the Applied group
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@brian-medley Yes I do
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Oh OK Thought I seen you supporting folks on the Applied group, I work For EMCOR Combustioneer in Washington DC , I also teach at Steamfitters local 602 in Washington DC,
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My guess would be the shaft seal. My experience with these machines is as you pull them down you basically cause the o-rings to magically dry out and start leaking. Same thing with the shaft seal. I would usually pull it down to 1000 microns and perform a standing rise test.
I know you’re far from that so if your pressure holds you probably might want to keep breaking the vacuum with nitrogen to see if that helps you.-
@jselvage them old YS chillers if we could get a 1000 mics on it knowing the seal is vulnerable we would do the same thing they will leak on you, the book even says if you get down to I think 1500 to 1000 and rate of rise is within limits gas it off quick to above freeze liquid rest of the way. I will see if i can find that bulletin that’s back in late 90’s early 2000’s sheesh dating myself lol
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Here is a little update on the chiller. I left it pressurized June 3rd at about 4pm at 200 psi. I came back this morning and it dropped to 194 psi in that 5 day period. I would consider that a big leak, but it’s nothing I can find. So now I’m thinking one of the tubes is busted. I’m just trying to picture this scenario in my head on how a vacuum pump would act while trying to pull a vacuum on a chiller that has a busted tube in it.
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@ronnie5 oil in pump would turn milky if it had water in the circuit or a busted tube. Has an eddy test been done before? The pressure drop your referencing. Did it have refrigerant in it? Massive temp swings will cause that much of a pressure drop or even rise.
If its the seal is in question why not submit a change order, or the least pull the seal out and completely soak / spray the seal and all O-rings with oil and re-vacuum and see if you get different results.
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@ronnie5 your 100% sure all of the hoses are tight? can you valve off the service valve on the machine with everything connected, and try and pull a vacuum with all of your gear set up and the micron gauge on it? just to be 100% on your equipment?
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@the-chiller-guys hose gaskets failure could be as well
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@brian-medley 100%,
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Your vacuum pump oil would turn milky
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Why are you attempting to pull a vacuum in the first place what is the original fault in the chiller ?
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@raptyr he had to replace something, and fix a leak if I remember
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Could be the shaft seal , put a bead of silicone sealant around the shaft to see if it reduces vacuum
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