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weight of water

Discussion in 'Commercial' started by Texas-Tech, Dec 30, 2017.

  1. Texas-Tech

    Texas-Tech Official Geezer*

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    duhh
    Damn thing shut down again today, low pressure alarm. When I restarted it the suction showed 56psig with 407c. At the time the water temp was 110° due to the fact the unit has a heater on it to keep the water from freezing. I don't understand why the suction would be so low with that kind of temp through the evap.

    Now it was about 33° ambient, unit has a single speed condenser fan with a cycling setup to I raised the fan on pressure to 310 psig on, with a 30 psi differential, and after running for about 45 seconds the pressure dropped all the way to 220. It was the only way to keep the low side over 60 psig.
     
  2. Chuck

    Chuck SSP

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    LAX
    What’s the superheat?
     
  3. tuna

    tuna New Member

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    2,931
    Do you have a way to know the flow through the heat exchanger? We had a problem last year with the mri we hooked chilled water to. Hate to say, but we put the wrong type of filter in the big blue filter. We had the type of housing that needed a cartridge filter, but had installed the bag type filter. There was a strainer in the mri that was getting cloggged because stuff was getting past our filter. We changed the filter several times and it was nasty, so we got lower micron filters. There are some more details, but holy shet was itembarrising when we discovered our mistake. So, I would make sure you have enough flow as low flow would cause your low suction.
     
  4. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
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    duhh
    Didn't measure it today but the accumulator is warm. I'd bet the sh was 40°
     
  5. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,970
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    IMT--in my truck
    JM is an offshoot of drake and about the same price-quality. no self respecting medical supplier would choose this chiller over a krauss, dimplex or filtrene for mri service. that said, your arrangement is for a chiller at or near the same elevation as the helium compressor not six stories up.

    at any rate, I digress. verify your filter is clean...damn near no pressure drop across it, or just open the bypass. make sure your solenoids are opening fully at the city water bypass panel ( if installed). make sure flow through the evap is correct( there are many that are not). finally get your pressure down, the medical equipment no likey that high pressure.

    low pressure could be a faulty switch, bypass to be sure while there. also make sure it isn't in parallel with flow switch as they sometimes do. there has been a run of bad flow switches on some medical use chillers.
     
  6. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
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    duhh
    This unit is cooling the helium compressor, supposedly on needs 2 gpm. When it's on city water it flows through a garden hose. Starting to wonder if this unit isn't oversized. I've seen a few 5 ton brazed plate evaps and this one looks more like a 2 ton coil but I think it's a 4 ton unit
     
  7. Ballvalve79

    Ballvalve79 It's only fire what could go wrong

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    Location:
    Northwest PA
    There is nothing wrong with doing the wrong be thing feeling embarrassed by it THE MAIN THING IS TO MAN UP AND MAKEGOOD ONCE YOU HAVE BEEN CALLED OUT ON IT. Sounds like you did. No worries about it move on and call it education.
     
    tuna likes this.
  8. tuna

    tuna New Member

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    2,931
    If memory serves me, the one we connected to needed 33 +\- gpm.
     
  9. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,970
    Location:
    IMT--in my truck
    if its only doing the helium compressor it could be oversized and require a pressure regulated bypass to maintain proper flow. you might be on to something.
     
  10. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
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    duhh
    On the mixing box on the wall there are gauges, sharpie says 40psi out, 80 I think in and 2gpm. We were pretty close to those pressures.
     
  11. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
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    duhh
    [​IMG]
    there is also this inside the unit, hot gas bypass I believe.
     
  12. Ballvalve79

    Ballvalve79 It's only fire what could go wrong

    Messages:
    274
    Location:
    Northwest PA
    Yes that is a hot gas velve them things can cause ye some greif if it's not set up properly.
     
  13. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
    Location:
    duhh
    It is supposed to be factory set and has a 90sec delay from when the compressor starts. The solenoid was energized but it was not open
     
  14. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,970
    Location:
    IMT--in my truck
    40 pound drop........
     
  15. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,970
    Location:
    IMT--in my truck
    are you sure or was it a maladjusted regulator(did you have a service magnet to test). under that dust cap is an adjustment usually allen wrench.
     
  16. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
    Location:
    duhh
    We had 130 psi on the incoming line in the equip room last week but today it had dropped 30 psi lower.
     
  17. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
    Location:
    duhh
    I could feel the solenoid was energized and had some heat going into the valve but the outlet of the txv was cold and transfered the temp up to the hgbp so I know it was closed.
     
  18. Texas-Tech

    Texas-Tech Official Geezer*

    Messages:
    17,958
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    duhh
    I was suprised by the amount of freon in the unit though
    [​IMG]
     
  19. crackertech

    crackertech assholiness *

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    Fl/IN/Ga/Ms/TX/NJ/VA/NC/TN
    That doesn’t mean the valve is open
     
  20. flange

    flange Act like you care and do SOMETHING!!

    Messages:
    12,970
    Location:
    IMT--in my truck
    that's a 5 ton machine. 2 gpm is on the low side should be closer to 10