Westerbeke 7.7 with model 21 dies when a/c is turned on

Discussion in 'General Maintenance/Repair Questions' started by Darrell Chapell, Feb 19, 2018.

  1. Darrell Chapell

    Darrell Chapell New Member

    10
    Jan 16, 2018
    1982 355T w/ diesel
    diesel detroit
    My generator dies when I turn on the a/c units. will run all day as long as I don't turn on the a/c units. Rear unit pulls 19 amps on line 1, but it runs the pump as well. front a/c on line 2 pulls 11 amps. I can turn on anything and everything except the a/c units. I can even run them by themselves. I can even run the rear only. I can't run the front a/c without the rear on for it tells the pump to come on. Which I am going to change eventually. But in the meantime can anyone help. Thanks
     
  2. Little Ducky

    Little Ducky Active Member

    768
    Jun 5, 2017
    Chattanooga TN/Dickson TN
    1998 SeaRay 290 Sundancer
    Twin EFI 5.0L w/Alpha 1 drives
    Do they run on shore power w/o any issues?
     
  3. Darrell Chapell

    Darrell Chapell New Member

    10
    Jan 16, 2018
    1982 355T w/ diesel
    diesel detroit
    Yes, every system works fine while on shore power. and no difference in amps pulled while on shore power.
     
  4. bahamabreisus

    bahamabreisus Well-Known Member

    Oct 25, 2007
    Hampstead NC
    500 dancer, previous 420,390,300 dancers
    detriot 8v92
    19 amps seems awfully high for the rear unit. are your units 110 volt or 240. If you are 110 volt system, just the 2 units are probably over powering the generator.
     
  5. Boater420

    Boater420 Well-Known Member

    Mar 11, 2015
    Clearwater, FL
    '97 330 Sundancer
    V-Drives
    Westerbeke 4.5BCG
    Twin Merc 454's
    I'd look at the rear unit. I also agree that 19amps seems pretty high. My unit only pulls 10amps with the pump.
     
  6. Darrell Chapell

    Darrell Chapell New Member

    10
    Jan 16, 2018
    1982 355T w/ diesel
    diesel detroit
    Thanks, I just looked up the specs on a new 16000 btu unit and it pulls 11 amps. but 19 amps does seem high. I looked up the pump specs and it should only be pulling 1.7 amps. I'm leaning toward the pump. I just got the boat so I have a few things to work out. It may not be the gen.
     
  7. Little Ducky

    Little Ducky Active Member

    768
    Jun 5, 2017
    Chattanooga TN/Dickson TN
    1998 SeaRay 290 Sundancer
    Twin EFI 5.0L w/Alpha 1 drives
    I'm not a electrician and I might not understand how things actually work...... but you would think it would trip the breaker somewhere if it was drawing that much power vs shut down the generator.
     
  8. BlueYonder

    BlueYonder Member

    114
    Jan 12, 2015
    Chesapeake Bay
    37
    QSC 8.3 600
    Might need a new start capacitor?
     
  9. Darrell Chapell

    Darrell Chapell New Member

    10
    Jan 16, 2018
    1982 355T w/ diesel
    diesel detroit
    I talked to a mechanic today and he said that the compressor on the a/c is about to go out. So new a/c is about to be purchased.
     
  10. LG111

    LG111 Active Member

    344
    Jan 4, 2015
    NW
    410
    8.1
    A buddy of mine was having simular issues after he bought a 2005 420 SB. So he bought a new solon A.C.. it set him back a bit but still had start up issues like you are describing... But it worked better than the old one. Several months later he replaced his house batteries and mysteriously his new A.C. unit works perfect every time. He was a bit pissed he was sold a new unit via the service guy. So just putting that out there. How old are your batteries?

    If your batteries are old and need a consant charge that adds amps to the start up on the A.C. knocking it down or out due to low voltage. (Not sure why that is). If my batteries are in a bulk charge via the geny, my main A.C. unit struggles to come on line. I am not an electrician, just describing what we have experienced and resolved.
     
  11. PlayDate

    PlayDate Well-Known Member SILVER Sponsor

    Dec 25, 2006
    Washington DC
    1994 370 Express Cruiser
    454 Mercruisers
    I believe that is the right answer. Clearly the load on that compressor is a problem. Normally they start tripping their electrical breaker when on shore power as well. The generator is far more load sensitive than shore power. You didn't mention how many hours were on the generator but their ability to handle heavy loads does decline over time.
     
  12. Darrell Chapell

    Darrell Chapell New Member

    10
    Jan 16, 2018
    1982 355T w/ diesel
    diesel detroit

    That's very interesting, I've never heard of that situation. I just got the boat so I'm going thru all the systems getting them current in maintenance. I think I'll check the batteries and 12 volt charging systems next. thanks
     
    LG111 likes this.
  13. Darrell Chapell

    Darrell Chapell New Member

    10
    Jan 16, 2018
    1982 355T w/ diesel
    diesel detroit

    I think it has about 2000 hours on it. I've been watching the rear a/c unit real close and it has started freezing up now and when I run just the fan. It actually cuts completely off even on shore power. So I'm thinking this unit is done for. It's original from 1982.
     
  14. barros57

    barros57 Member

    33
    May 19, 2015
    Lake Minnetonka, MN
    350 Sundancer 1991 "Sunny Daze"
    268 Sundancer 1987 "Offshore Drilling"
    454 7.4L Mercruiser Bluewater Inboard, Hurth V Drives
    350 5.7L Mercruiser 260/V8
    The coils on the ac unit are freezing up? Does it work on heat mode?
    Maybe it is overcharged or your reversing valve is sticking causing the compressor to work too hard.
     
  15. joeyleggz

    joeyleggz Member

    292
    Jan 15, 2013
    long island
    current boat: 1997 sea ray 330 express cruiser
    twin 454's efi
    I have noticed when my generator is cold and I turn on the air-conditioner it’ll Bogg down not kill the generator but it resets the AC After the Genny runs for about 10 minutes and gets warm that every system works perfectly fine only in the beginning anything that draws a quick 20 A on the start up wI’ll bog down the generator Westerbeke 4.5
     

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