Samsung frenchdoor making intermittent compressor noise

[IDoSeaDoo]

Hey guys I have a RFG297 and I've recently had to patch a small hole in the evaporator pipe. After filling it with freon, I noticed a little oil leaked out when I was evacuating it. I'm not exactly sure how much oil, but i'm guessing no more than 5ml. Well, I filled it back up with freon till the pressure read roughly 115 on the high and 0 on the low. I was not able to get the exact amount of freon that I put in because the pressure started to rise too high before I could put in the 5.39oz that the rear of the unit specifies. However, I do not trust my scale, especially since it's measuring a small can of freon with a fat hose attached to it. Anyway, the fridge seems to be working well. I'm not sure I'm reading the temperatures accurately as I don't trust my temp gauge at 0degF, but in the fridge, it's about 3-6 degF off of what the digital setpoint reads.

My main concern is that the compressor always seems to be running, and makes this intermittent shudder/vibration noise. Does anyone know how much oil should go into that unit? The manual says it needs Freol @ 15c... idk what that means. Is there a way to tell how much you have in there? Is there a way to remove the oil in there and add a new charge?

Someone on this forum told me the pressure should be 0 and 105 on the low and high respectively, can anyone verify that?

Thanks!

[JWWebster]

An ice box and a freezer and a water fountain or Coke machine all run on the same low side pressure which is 5 PSI.

When I charge an ice box I never allow the gauge to go above 10PSI at anytime. i slowly add in a little at a time till it stays at 5 PSI.

[IDoSeaDoo]

Those noises are really bothering me... why would it make those? I think the compressor is running particularly loud too, I could hear it all the way down the hallway last night.  Could low oil make it do that?  I turned the temp up as high as it would go to alleviate it. I really hope it doesn't die before I can figure this out 

[JWWebster]

How long did you vacuum it out before you decided to recharge?

[IDoSeaDoo]

Probably 1.5 hours or thereabouts. When I evacuate a system, does it suck the oil out?  How much oil goes in these compressors?

[JWWebster]

Unless you turned the ice box upside down you didn't loose that much oil. Gemline used to make an oil to add that would quiet down noisy compressors but they are out of business.

[tgoods]

JW, I don't know how you get away with 5psi on 134a.  That will usually cause a severe overcharge.  0 psi is about right when the fridge is at operating temperature.

What does your frost pattern look like? Is there any frost on the suction line to the compressor?  You shouldn't have a problem with compressor oil unless you lost a lot of it.  How long was the system exposed to air?  Moisture and these poly oils don't mix well.  Just curious, how did you patch the hole?

[IDoSeaDoo]

I patched the hole with MAPP gas and aluminum brazing rod. It was not exposed to air. I put a vacuum on it and brazed it by melting the  brazing rod over the hole. My low press is 0 or maybe slightly less. There is frost on the inlet pipe of the compressor, haven't taken apart the inside of the fridge to check out the frost patterns. Would a strange frost pattern cause the compressor to intermittently struggle though?

[AJ]

Probably 1.5 hours or thereabouts. When I evacuate a system, does it suck the oil out?  How much oil goes in these compressors?

You really need to use a Micron Vacuum Gauge to tell if you have a good vacuum on it. How else are you going to know if there is still any moisture in the system?

[JWWebster]

It has been my experience that if you over charge a unit frost will form on the ear and you know you have too much. Also you can check amp draw while charging. I ain't got no problems with 5 PSI as long as I put the gas in slowly. I also listen to a compressor while charging. It will tell you when it is happy and when it is not. It will flat out lock up if too much gas is added. I always charged my R-12 units to 5 PSI and when these new fangled ones came out with R134A I did no different. Never had any problems. You gotta remember these units are factory charged in Mexico. The altitude is over a mile above sea-level. So 0 PSI might be fine there but not here at 15 feet above sealevel. That is why so many ice boxs have a low charge that come out of Mexico. My opinion.

[tgoods]

There is frost on the inlet pipe of the compressor

You're overcharged.  The noise might liquid slugging in the compressor (not good).

Did a compressor change out a few months ago.  Weighed in the charge with a digital scale.  Was running at a 5" vacuum but was cooling fine, good frost pattern.  Then I realized I keep my shop at 60 degrees.  Bumped up the heat to 68, emptied the liquid from the high side hose and got it to the 0psi lowside I like to see. Maybe your hot weather is why your pressures are so high.

Sorry about the slight thread hijack.

[IDoSeaDoo]

You were right guys, I was overcharged. I let out some pressure on the high side till the low went down to 0 (it now rests slightly below that, but my gauge might be off slightly) and the high is around 105 or 110. The fat pipe (or ear as someone called it) sticking into the compressor is no longer frozen over either and the ominous shudder is gone. It still seems to be cooling 10degF higher than the setpoint in the freezer and about 4degF in the fridge, but I attribute that to my less than accurate thermometer, and am okay with a bit of error. As long as this thing works THIS WELL for the next 5 years, I'll consider this endeavor a success. Thanks for the input guys!! I hope I can retire this thread after this post

[tgoods]