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Lobster Tank

Since your compressors are located above the chiller barrels and we are talking about evaporator saturation temperatures in the 37 degree range, are there traps in the suction line at the outlet of the barrels?

Losing a scroll in such a short period of time seems very strange.

Comments

  • Techman
    Techman Member Posts: 2,144
    Lobster Tank Pumps

    Professer? Mike T? or?-Having read several THREADS on over pumping of boilers,I wonder how over pumping of chiller barrels takes place. How would I recognize that I have a problem ? This is in reference to Seafood Shop Lobster Tanks that typicaly utilize residential pool pumps.How would it affect my suction press? Superheat?
    Thanks!
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Overpumping

    Overpumping on a chiller barrel will result in higher suction pressure and a low delta-t across the water side of the chiller.

    This is because the amount of water moving through the barrel increases, resulting in more heat added to the refrigerant. This causes the suction pressure to rise. Because the water is moving faster, the amount of sensible heat picked up between the inlet and outlet of the barrel will drop.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Just an addition to the above

    Since the water is moving to fast to properly cool the load in the tanks, your first complaint will be that the product is either getting to warm or the water is to warm. The pump is actually critical in this situation and has do deliver a set gpm to maintain the water temps. You could throttle down on the valves in the water side but make sure, if there is a flow switch that you still have enough flow. They do make flow gauges which can aid you at a glance as to what is happening in the water side of the system.

    Mike T.
  • Techman
    Techman Member Posts: 2,144
    Dead [ Sea] Scroll Compressor

    Professor? Mike T.? Hi! I have another Lobster Tank system at a different location. There are 4-chiller/condensors/pump units.#4 had a bad compressor-a Copeland Scroll -5hp-1ph-208-230,which I changed out today.The comp.is in warranty from the "Install Company" .The comp is grounded and shorted with hi acid levels.Goodman Residential A.C. Condensing Units.Water Pumps run continously through one common tank so all 4-chiller barrels have water flow.Now to my question,Unit #4 does not run very much compared to #1#2#3 ,so,when #4 is idle would the refrigerant migrate to the 35-45* chiller barrel and slug the compressor upon startup.Scrolls are hard to kill,this one died in only 11 months.Thank You For The Use Of Your Brain's
  • Empire_2
    Empire_2 Member Posts: 2,343
    Will get back to ya soon, but

    lead / Lag control on this application is almost a must. Be back in about 4 hrs... By the way "T" I'm getten hungry!!!!! Also Techman,...Where are your condensers in relation to your chiller berrel set up?

    Mike T.
  • mtfallsmikey
    mtfallsmikey Member Posts: 765
    While it's fresh on my mind..Calling Dr. Silberstien!!

    Have you had any experience with Trane self-contained commercial units? Each unit has 4- 20 ton scrolls, using condenser water from cooling towers. I have 12 of these in 2 buildings that I run, and maintenence has been very poor, units are 5 yrs. old...if you do, I'd like to pick your brain a little bit...Thanks!
  • David_5
    David_5 Member Posts: 250
    accumumlator

    Does the system have an a accumulator? Is there a solenoid in the liquid line? Is the condensing unit outside? How cold does it get around the condensing unit? Does the unit run year round? Answer these questions and more specific advice can be given.

    David
  • Techman
    Techman Member Posts: 2,144
    Dead Scroll

    Hi David,So far I've added Fan Cycle Control's,C.C.Heaters,Hi& Low Press Safety's and Time Delay.There are Liquid Line Solenoids but they are wired from the "load side "of the contactor,Not set up for pumpdown.Copeland Co. says the compressor has built a in discharge check valve .So that means the system can be changed to a pumpdown, with the addition of a hard start kit.Another company put this system ,now I get to make the system safe for the compressors.I REALLY LIKE finding the cause of what killed the compressor,and I REALLY REALLY LIKE fixing the problem{s]
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Pick Away!

    Shoot.

    I'm sure that if I cannot help you there are many talented people reading this right now!
  • Empire_2
    Empire_2 Member Posts: 2,343
    T-Man

    Are these compressors 3 PHZ? Also, the checks are there to prevent dead headding the compressor in cooler weather.

    Mike T.
  • Techman
    Techman Member Posts: 2,144
    Dead Scroll

    Hellow Again!Condensors are 1phase.Condensors are located 4-8ft from the chiller barrels and 2-3ft above the chillers barrels.
  • Techman
    Techman Member Posts: 2,144
    MIKE T.

    Hay Mike .Units are 1phase
  • Marty
    Marty Member Posts: 109
    low bid

    How about a picture ? I'm curious how long it will take for the added parts and repair costs to equal the price of doing it right the first time.
  • Techman
    Techman Member Posts: 2,144
    anothermarty

    Hi, I don't mind "low bidders", they help me make a living by allowing me the oppertunity to sell and install a lot of parts and labor.
  • David_5
    David_5 Member Posts: 250
    compressors

    If the condensing unit sits outside and it gets cold, refrigerant can migrate into the crankcase on the off cycle. The C.C heater helps but pumpdown is better because the refrigerant cannot migrate. It sounds like the L.L. solenoid is at the condensing unit. It should be as close as possible to the TXV. A fan cycling control also helps because the TXV will be eratic with low head pressures. An accumukator is also cheap protection. If you really want to find the cause of the failure, cut open the old compressor. Call Copeland and tell them what you see. They'll help you figure it out.
    I was taught by Copeland that compressor don't just die, they are murdered.

    David
  • tim smith
    tim smith Member Posts: 2,360
    dead compressors

    I would say that pump down controls and accumulator is a necessity for this imho. good luck.
  • Techman
    Techman Member Posts: 2,144
    Scroll -R.I.P.

    Hi Professor, There are not any traps in the suction line.Should there be traps in this system? I agree with you, Professor,compressors are supposed to last a long time.Thanks.
This discussion has been closed.

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