Trane screw problems

[coolinggod5]

My company recently put in a CHHA 200 screw compressor on a 1988 RTHA 215 chiller. I had Trane out to put new compressor into service and do the initial checkout on startup. Everything looked good and compressor ran for a week, and then started loading to current limit without the load solonoid energized, then would unload solonoid would bring amps back down, and the second the unload solonoid de-energized, the compressor would load again. Performed pressure test at solonoid and pressure bled off meaning the copper line at the front of the compressor (internal) was broke. Worked with Trane and we found that the flare itself had cracked. Made up a new piece, and installed. Ran one week, same thing. This time we took the oil separator off and made sure it was tight and not vibrating, and installed a factory oil line where the flare had cracked again. Put unit back into service, and one week later, its loading again. I believe the compressor is getting changed out this time, but I am just baffled as to what may be causing this problem. The last compressor was original and lasted 70,000 hours, and the check valve in front of the rotors had failed and on shut down it would run backwards, and also compressor had a bearing dragging on startup. Anyone have any insight or opinions on what the heck is going on?

[jayguy]

somebody needs to learn how to flare. the flare cracking is an issue on long run hour units but not on something new. a loose nut, maybe. i would recommend replacing the copper tubing...i have never tried it (never needed to try it) but how about installing a stainless steel line?

[coolinggod5]

You know I mentioned a stainless line with swedge lock fittings at each end, and the response from Trane, which I have to agree, was "thats not fixing the original problem." I couldn't argue with that.

[Southern Mech]

Sounds like a harmonic problem has developed either from new compressor issue or a movement in suction or discharge pipe.
This is hard to discuss on the internet cause I can't feel the vibes.

[coolinggod5]

You know you mention harmonics and at different frequencies the external oil lines have a "buzzing" noise, and it sounds like it originates at a checkvalve just past the oil solonoid. I honestly don't know and was just hoping someone had seen this before, but it appears I am the lucky winner. I appreciate everyones input though.

[codgy]

replace oil solenoid and check valve see if it clear up issue.

[cperk]

My company recently put in a CHHA 200 screw compressor on a 1988 RTHA 215 chiller. I had Trane out to put new compressor into service and do the initial checkout on startup. Everything looked good and compressor ran for a week, and then started loading to current limit without the load solonoid energized, then would unload solonoid would bring amps back down, and the second the unload solonoid de-energized, the compressor would load again. Performed pressure test at solonoid and pressure bled off meaning the copper line at the front of the compressor (internal) was broke. Worked with Trane and we found that the flare itself had cracked. Made up a new piece, and installed. Ran one week, same thing. This time we took the oil separator off and made sure it was tight and not vibrating, and installed a factory oil line where the flare had cracked again. Put unit back into service, and one week later, its loading again. I believe the compressor is getting changed out this time, but I am just baffled as to what may be causing this problem. The last compressor was original and lasted 70,000 hours, and the check valve in front of the rotors had failed and on shut down it would run backwards, and also compressor had a bearing dragging on startup. Anyone have any insight or opinions on what the heck is going on?

We had a 1000 psi flexible hydraulic hose made and installed on one that broke a couple of times. It's been about 4 yrs and no problems.