New user.. asking a “dumb” question.. pump cycling

Discussion in 'General Discussion' started by Jessica Gardner, Aug 9, 2022.

  1. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    Hello. As a new owner of a 2000 340 SD. we stayed our first night on the boat and I slept down in the lower bed under the stairs, all night long there was a loud pump or something running, it would cycle off for a short period then on again… what pump is this and is it normal? The AC was set to 68.
     
  2. mrsrobinson

    mrsrobinson Well-Known Member SILVER Sponsor

    Mar 9, 2006
    Virginia, USA
    2001 Sea Ray 380DA
    3126 purring CATs
    Sounds like the vacuush for your holding tank. Could also be the water pump for the air conditioner
     
  3. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    Not the vacuflush. I have learned that sound. My husband also said it is the pump for the air conditioner, is it normal for it to run almost constant all night long, shutting off only a few times and for only a min or so.
    Only reason it concerned me is we are also tracking down a leak in the engine compartment bilge area.
     
  4. mrsrobinson

    mrsrobinson Well-Known Member SILVER Sponsor

    Mar 9, 2006
    Virginia, USA
    2001 Sea Ray 380DA
    3126 purring CATs
    Mine comes on when the compressor comes on.

    Yeah I saw your other thread and thought about that as well. If you were running a generator while on anchor and running the AC that could be the source. The pump probably sits directly behind your firewall but I don't know on that boat, others can chime in. Easy enough to find, when you hear it running open the engine compartment and look for the noise.

    It should have its own dedicated seacock, so should both of your engines and the generator. When you're under anchor you can try closing them one by one and see if your problem goes away as well.
     
  5. Strecker25

    Strecker25 Well-Known Member

    Nov 20, 2014
    Rochester, NY
    2002 410DA
    Caterpillar 350HP 3126
    Is it a buzzing/vibrating sound or a constant hum? If it’s the buzzing sound it is your freshwater pump as those are diaphragm based and knowing the other thread and how you’re chasing the leak nearly confirms your source of water to be the freshwater system.

    a common place they fail is right at the inlet to the pump, there’s a plastic saucer looking thing that holds a filter screen and they love to crack
     
    Jessica Gardner likes this.
  6. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    1998 450 Sundancer, Achilles dinghy w/15hp
    3126 Cat's
    Go to your panel and turn off your fresh water pump... If it stops you have information on what you should do next.
     
  7. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    Thank you all, I will check that next
     
  8. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    i feel like it was a humming noise very loud in that lower bed, but you could also feel a vibration as well so I could just be thinking too hard about it now. I will rule out the fresh water pump this week. Thanks for your help. I will report back just for others to reference
     
  9. Wanderer 290

    Wanderer 290 Well-Known Member

    724
    Jul 1, 2019
    Traverse City
    01 sea ray 290 sundancer
    Twin 5.7 b3’s
    The hum could be the converter?
     
  10. Little Ducky

    Little Ducky Well-Known Member

    Jun 5, 2017
    Dickson, TN / Chattanooga, TN
    1998 290 Sundancer
    Twin EFI 5.0L w/Alphas
    Kohler 4kW
    Where does your AC condensate go?

    There should be a sump in the lowest part of your boat for AC and Shower drains.

    Is that what you are hearing?

    If that sump pump is loud it might need cleaned really good or replaced.
     
    Chris-380 likes this.
  11. wayne0

    wayne0 Active Member

    535
    May 4, 2014
    Newburyport, Ma.
    2000 340 Sundancer
    Twin 7.4 ltr.V-drives
    I have the same boat. The AC pump is on the other side of the wall. Fresh water pump too. My money is on the AC pump.
     
    Jessica Gardner likes this.
  12. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    Thank you! So I assume if it is the AC pump running all night it is normal for it to run while the AC is running/trying to keep up with the temp it is set to.. sorry I’m not the mechanically sound one in the relationship and sometimes my husband doesn’t like to answer my “make me feel better about this questions”
     
  13. bfernald0

    bfernald0 Active Member

    270
    May 18, 2020
    Marina del Rey, California
    340 Sundancer 2001
    8.2L Mercruiser ECT Horizons
    The A/C pump is going to cycle on and off with the A/C compressor and fan. If the A/C is running, the A/C pump is running.

    If what you are hearing continued after the A/C cycled off, then it's not the A/C pump. If it's the water pump, which is located on the bulkhead between the after sitting area/bed and the engine room, you in all likelihood have a leak somewhere, which is causing the water system to lose pressure and the pump to cycle on and off. Ordinarily, the water pump should only cycle when you flush the toilet or open one of the faucets. Additionally, when the water tank is low, it will stay on because it isn't able to prime. As Bill Collector suggested, this is a pretty easy diagnosis.

    Start by turning the A/C off. If no more hum or pump noise, it's the A/C. If there is the same noise, turn off the water pump on the circuit panel. If no more hum or pump noise, it's the water pump. Etc.

    The two other pumps it could be is the sump, under the floor hatch next to the head. Doesn't sound like that's it, based on where you are describing the noise as coming from.

    The other one is the forward bilge pump under the hatch in the middle of the aft seating area. I have the same boat (2001), and that one would go on and off due to a fault float switch.

    The sump and forward bilge pumps can't be easily switched off, so you'll have to access them when you hear the noise to determine if that's it. The forward bilge pump will also light up on the engine monitor on the dash when it cycles.

    Very doubtful the battery charger (i.e., the AC Converter on the breaker panel) would cause that level of noise, but again, it's easily switched off. If you switch it off and noise goes away, you found it!
     
  14. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    Your comments are extremely helpful. Thank you for responding and not judging my ignorance, as I want to learn as much as I can about the boat as well
     
  15. bfernald0

    bfernald0 Active Member

    270
    May 18, 2020
    Marina del Rey, California
    340 Sundancer 2001
    8.2L Mercruiser ECT Horizons
    At this point, I've been through ever square inch of my 340. Engine repower, generator rebuild, electronics redo, etc. etc. etc. etc. etc. Happy to attempt to answer any question you may have about a circa 2000 Sea Ray 340 Sundancer.
     
    Jessica Gardner likes this.
  16. bfernald0

    bfernald0 Active Member

    270
    May 18, 2020
    Marina del Rey, California
    340 Sundancer 2001
    8.2L Mercruiser ECT Horizons
    Also, by "aft seating area" I'm not referring to up top in the cockpit. I'm referring to the seating area/bed in the aft, under the cockpit. There's a carpeted square hatch right in the middle of the floor with a bilge pump and float switch under it.
     
  17. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    1998 450 Sundancer, Achilles dinghy w/15hp
    3126 Cat's
    Jessica, you are in the right spot. We are CSR and we are here for each other...
     
    techmitch and Jessica Gardner like this.
  18. bfernald0

    bfernald0 Active Member

    270
    May 18, 2020
    Marina del Rey, California
    340 Sundancer 2001
    8.2L Mercruiser ECT Horizons
    I'll echo this. Just about every problem I've had, I've been able to fix myself based on prior posts on this site. It is truly an invaluable resource for Sea Ray owners.
     
  19. Jessica Gardner

    Jessica Gardner New Member

    23
    Aug 4, 2022
    Louisville, KY
    2000 Sea Ray 340 Sundancer
    7.4 454 Mercruiser with V drives
    i have lifted this hatch before and we did see the bilge so I am aware of where you are talking.. We are anxious to get down to the boat on Friday and roll up our sleeves and start problem shooting for this as well as tracking down our slight water leak in the engine bilge area.
     
    Little Ducky likes this.
  20. boatrboy

    boatrboy Well-Known Member

    Oct 3, 2006
    Orange, CT
    2006 340 Sundancer
    Twin 8.1 Horizons with V-Drives
    FWIW - I don’t even know if you have a cockpit refrigerator, but on my boat I noticed the same thing. It turned out to be the fridge compressor kicking on and off. It hums and vibrates a little.

    Good luck in your investigation.
     
    SeasNT and Jessica Gardner like this.

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