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Chiller troubleshooting

Discussion in 'HVAC' started by Pascal, Jul 29, 2021.

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  1. Pascal, Aug 4, 2021
    #41
    Pascal

    Pascal Senior Member

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    The system was cleaned and descaled 6 weeks ago

    36 hours ago, I switched to the nr 2 sea water pump and the breaker has held for 24 hours. Coil temps have dropped 5 to 7 degrees. The more I think about it the more I suspect the nr 1 pump is tired. Going to pull it and check the impeller.

    Yesterday was overcast here in Miami so chiller nr 3 was cycling on and off as needed :

    66A7AD78-8741-4B35-BA31-DBE8479DFE0C.jpeg
  2. rtrafford, Aug 4, 2021
    #42
    rtrafford

    rtrafford Senior Member

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    Ok, so different source, but technically the same issue driving the breaker trip. The breaker is tripping to save your gear, and the amp imbalance (?) is suggesting to the breaker it should respond. My amps only went up perhaps 3 or 4 on one side, and stayed below the breaker threshold. But it tripped, and the driver of the trip was the higher operating temp of the compressor.
  3. rtrafford, Aug 4, 2021
    #43
    rtrafford

    rtrafford Senior Member

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    ...and I'm telling you this as much as I'm asking, learning here. My issue was very similar to what you're explaining, it seems, and mine was temp driven by buildup on the coils. Your temp issue is driven by a pump...right?
  4. Pascal, Aug 4, 2021
    #44
    Pascal

    Pascal Senior Member

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    Not sure yet. I have to suspect pump nr 1 since on pump nr 2 the breaker hasn’t tripped in 28 hours and temps are a little cooler.
  5. rtrafford, Aug 4, 2021
    #45
    rtrafford

    rtrafford Senior Member

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    ...but in the end I think you'll find that your breakers are fine, guilty of doing what they were designed to do. Mine as well.
  6. Capt J, Aug 4, 2021
    #46
    Capt J

    Capt J Senior Member

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    Shut chiller #3 off and that will load 1+2 if it's overcast tomorrow......
  7. Pascal, Aug 4, 2021
    #47
    Pascal

    Pascal Senior Member

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    It tripped a couple of hours ago. Coil temps were 5 to 6 degrees higher 10 minutes after restart. Not quite sure why. ER room temp was higher because I had not reset the blowers after running on gen for a while while testing it. Don’t think 15 degrees ambient temp in the ER would really make a difference but at this point who knows.
  8. johnnry, Aug 5, 2021
    #48
    johnnry

    johnnry Member

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    Sorry for the delayed reply..what is the leaving water temp out of the chillers? The delta T across chillers is important..sorry mapism,between my dyslexia and your accent..
  9. Pascal, Aug 5, 2021
    #49
    Pascal

    Pascal Senior Member

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    Each chiller has 3 sets of coils. Bottom of each set is about 96 degrees, top is around 118. Sea water is about 90 degrees
  10. rtrafford, Aug 5, 2021
    #50
    rtrafford

    rtrafford Senior Member

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    And all three coils are reading the same, all three coils sit on the same plane of installation?
  11. Pascal, Aug 5, 2021
    #51
    Pascal

    Pascal Senior Member

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    Yes within two degrees. All three chillers are in the same shelf so no variation in water flow
  12. rtrafford, Aug 5, 2021
    #52
    rtrafford

    rtrafford Senior Member

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    Two degrees can be the difference if already stressed by hot seasonal water. Only one unit is tripping?

    I'm still in the camp staring at your coils and saying clean them and backflush them for possible blockage buildup. I might be alone in that camp, but that's my experience. I'd hook up a hose to your discharge port on the manifold, a hose on the input port, introduce a pump to your hose to the discharge side, and start pumping RedLine coil cleaner or similar backwards into and back out of the bucket, watching for sediment and debris. I'd run that cycle for an hour, then reconnect the discharge side and pump fresh water through and out. Likely I'd shut down the intake and soak the sea strainer at the same time I'm doing all of this.

    Temp leads to amp creep, and amp creep trips these breakers.
  13. Pascal, Aug 5, 2021
    #53
    Pascal

    Pascal Senior Member

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    No, chiller nr 1 and nr 2 are on the same breakers on the main panel and that s what’s tripping. Chiller nr 3 is on the second breaker which also powers the pumps.

    so far using a clamp meter max function has failed to catch a high reading that would cause the tripping.

    since the system has recently been cleaned, I m leaning towards a pump issue. I ve had problems before on another boat where the bronze impeller in these Scott pump got eroded with age.
  14. Pascal, Aug 5, 2021
    #54
    Pascal

    Pascal Senior Member

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    I pulled pump nr 1. Impeller shows some erosion and the two holes are slightly bigger than the spare shown in the picture.

    what I am questioning are two holes in the pump body in pic nr 2. I ve never opened one of these before but can only guess they have to affect flow. I doubt they are meant to be there.

    DD235E93-07C9-4FAF-9DFB-32B91C6CCAF2.jpeg 8B70D84C-8F26-40A7-AA78-9F821B5C3184.jpeg
  15. Capt J, Aug 5, 2021
    #55
    Capt J

    Capt J Senior Member

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    I think you have a weak circuit breaker. Generally if a pump doesn't have adequate flow it will happen right away, or you'll get high pressure readings.
  16. Pascal, Aug 5, 2021
    #56
    Pascal

    Pascal Senior Member

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    I replaced the breaker last week...
  17. johnnry, Aug 6, 2021
    #57
    johnnry

    johnnry Member

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    Pascal, those holes are to let air out of the pump volute when shut on and off..many manufacturers put them in general purpose style pumps so pumpsbdont get airlocked on start..minimal performance loss.. so I am unsure if you have chilled water or freon going to the actual airhandlers in the boat..the Temps you give are for the seawater heatexchangers yes?
  18. Pascal, Aug 6, 2021
    #58
    Pascal

    Pascal Senior Member

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    Thread title is chiller troubleshooting... so obviously talking about a chiller system. Not remote condensers
  19. johnnry, Aug 6, 2021
    #59
    johnnry

    johnnry Member

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    Ok so what have the entering and leaving Temps been to the airhandlers?
  20. johnnry, Aug 6, 2021
    #60
    johnnry

    johnnry Member

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    If you don't have IR temp scanner, how about head pressures while operating ?
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