Results 1 to 12 of 12
  1. #1
    I am starting up a liebert one and a half ton split system in a few days that we are installing in a MRI computer room. We added about 60 feet of line set and installing their quick connections. I have just finished school and pretty well understand the refrigeration cycle. I am pretty decent with small stuff. I worked maintenance at a casino taking care of all HVAC equipment; chillers, RTUs, Splits all kinds of coolers. Now I am a start up tech and installer in the field for a union contractor since finishing school. Getting thrown to the wolves as they say and am getting a little overwelmed with the variety of equipment I am starting and all the different manufactures requimendations for start up.And some of the things from school education are different from manufacturers and what older techs are saying. Long story short I have installed about a hundred of these mini mates when I was installer but never started one up. I want to know if anybody here that has had a lot of experience with starting these up would share with me about the proper amount of refrigerantto add to these after istalling such a long line set.The manual tells you a little bit about adding something like 40 ounces. I have read in Tranes manuals to brake the vacuum with the R22 until the line set and drum equalize and then open the compressor valves to relase factory charge to the line set.I have seen many techs do it different ways so I would like a little more expert advice into this comflict I am having about the right way that would kind of help me across the board with this unit and most others about this way of charging new install.

  2. #2

    ....

    There should be a sight glass on the LL, Go by that.

  3. #3

    ...

    is it air or water cooled?


  4. #4
    Join Date
    Sep 2006
    Location
    Independence mo
    Posts
    34
    Liebert has a chart in the manual that has all of the calculations for evap line set etc. But to make it verry simple Liebert wants 15 deg + or - 2 SH not sc allong with a clear sight glass if this unit does not have lee temp. On the start up sheets they dont even ask for sc but you should still check it. What year apprentice are you?

  5. #5
    Join Date
    Aug 2006
    Posts
    2,603
    Should be a manual inside the unit and a Start-up sheet that must be filled out for warranty. I would sign the sheet in pencil as Liebert was requiring Factory certified techs. for start-up. (Hint get your boss to send you to their school)There is a rubberband on the float in the condensate drain, a lot of miniMates are drain trapped inside, so look for double traps. Liebert condensate pumps get wired to the unit and have high water alarm that must be plugged into unit, check wiring diagram. Also check tightness of Aeroquip fittings at CRAC unit and remote condensor, most installers don't snug them up enough. Check install manual on this. Also miniMates DO NOT get hung by strapping, there is a special bracket, with rubber compressor bushings, supplied with unit, and to customer supplied allthread to above.

  6. #6
    Join Date
    Sep 2006
    Location
    Winter Springs, Fl
    Posts
    1,755
    If this unit has a HGBV, remove power( pull wire at contactor ) to it so you can get the proper charge dialed in. After initial charge is done you will have to dial in the HGBV by adjusting it like a TXV. max out the tstat so it does't shut off. Go a 1/4 turn at a time and wait 15 mins bewteen adjustments until the unit constantly runs at the design setpoint ( sometimes this is hard because they usually don't have a full heat load in the room at the time ). a lot of this is covered it the IOM that is shipped with the unit. Make sure that the control board dips and the tstat dips are set to what is installed in the unit or to the customers needs/blueprints ( i.e. dehumidification, humidifier, HGBV, SCR or elec. reheat, etc... )remove power to unit before setting dips or the system wont see the changes plus it might do damage.

    Just as madhat stated, you need to check the aeroquips for proper tightness ( 1/4 turn AFTER you feel it bottom out ) and also make sure the drain is not trapped outside of the unit. I once had the aeroquip fitting on the liquid line at the condenser not pierce open and had to recover the charge, dig all of the metal out, reinstall the line and recharge to get the system running ( of course this was down at the end of the job and didn't really have the time for this little setback ). On longer linesets its good to break the vac w/ refrigerant and wait for it to equalize, then open line to system. the vacuum helps fill the line quicker.

    I hope all of this helps

  7. #7
    Join Date
    Mar 2003
    Posts
    7,326
    Liebert has charging procedure in manual. you can only use the lineset chart as a reference, but still must check superheat/subcooling etc. as already stated if this is setup for year round operation in cold climate, you will need to follow their procedure or you will be f'ed. good luck. As far as Factory certified techs, liebert generally considers ua personnel capable of factory startups.

  8. #8

    ericnye

    air cooled

  9. #9

    springerray

    what is -2 SHand SC? I am a Journeyman turned out in 1999. Pipefitter got into instalation after turning out with some past experience. Contractor I was working for said I needed to go back to school for service and come back when I finished and with experience. So I can do install and start up. Got out of the union for two years went to two year school and worked maintenance at local casino during school. They hired me back at a great timing for construction and start up.I am there start up man and help with install and surveys.But still learning and going to school back at the local for building automation. So long story short I am a secound year lol.

  10. #10
    Join Date
    Sep 2006
    Location
    Winter Springs, Fl
    Posts
    1,755

    Re: springerray

    Originally posted by alantennessee1
    what is -2 SHand SC? I am a Journeyman turned out in 1999. Pipefitter got into instalation after turning out with some past experience. Contractor I was working for said I needed to go back to school for service and come back when I finished and with experience. So I can do install and start up. Got out of the union for two years went to two year school and worked maintenance at local casino during school. They hired me back at a great timing for construction and start up.I am there start up man and help with install and surveys.But still learning and going to school back at the local for building automation. So long story short I am a secound year lol.
    He was referring to the superheat measurement: 15 degrees F + or - 2 degrees ( total of 4 degrees swing ) . he said not to worry about subcool which I agree. I check it as part of my startup proceedure but dont really use it to charge the unit. the book explains the exact method for dialing in the charge. If you dont have it you can download the PDF from liebert. http://www.liebert.com

  11. #11
    Join Date
    Sep 2006
    Location
    Independence mo
    Posts
    34

    Cool

    When you get the startup done let us know how it went.Im a 5th year and was lucky enough to get in with a good contractor. They sent me to liebert start up it was a verry good class, I would recommrnd it to anyone!

  12. #12
    Join Date
    Sep 2004
    Posts
    86
    If you are going to be starting up or having anything to do with Lieberts you should attend one or more of their classes. They may have one locally or you can attend at their training site in Columbus Ohio. Their classes are excellent. Been to 4 or 5.

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