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Air conditioners stop working

Discussion in 'Technical Discussion' started by Dan balmer, May 14, 2018.

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  1. Dan balmer

    Dan balmer New Member

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    air conditioners stop working on offshore trip on 50 Post with 15 kw westerbeke running but it seem to be surging in rpm. Anyone know what problem is?
  2. MBevins

    MBevins Senior Member

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    Could be anything based on the description. Have you confirmed water flow? No water will cause compressor to increase current draw and load up the gen. Are all units doing the same thing? If so you probably have a common water pump.
  3. Dan balmer

    Dan balmer New Member

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    All the units stop working (3) and each has separate water pump that is clear of debris so it’s a power problem of some sort associated with the generator.
  4. MBevins

    MBevins Senior Member

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    Then I'd suggest you start with the generator, start one at a time and see if the Gen starts to overload. Watch the ameter on the panel so you can measure increase load.
  5. Pascal

    Pascal Senior Member

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    You need to start by defining "stopped working"

    Do the air handlers work, do you have power on the controls? do the breakers trip? How much voltage do you have on the panel? You said the generator seem to be surging, how about frequency? If rpm varies on a generator it will affect frequency not voltage.

    Need more details. We re not psychics.
  6. Capt J

    Capt J Senior Member

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    After what pascal said. The first thing I’d start with on the generator is to change the primary and secondary fuel filters.
  7. kiffa

    kiffa New Member

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    Hi on our 12.6 there was a faulty electric governor sensor that caused ours to hunt very bad, this may be the case with yours.
  8. Dan balmer

    Dan balmer New Member

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    Thanks everyone for your responses. I’m fairly sure that the generator is not producing the right electricity and the 3 units don’t like it and turn off Will ck engine details and then electricity details of generator Have an expert coming to ck it out. Again thanks
  9. Dan balmer

    Dan balmer New Member

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    Hello everyone. Just wanted to get your thoughts on my generator starting to act up when the engine room space gets above a certain temp. It runs fine until I come off plane and idle or stop. Then the generator starts acting up and won’t run the air conditioners. Any thoughts?
  10. Pascal

    Pascal Senior Member

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    Can you please define "acting up"? Does it throw a tantrum and yells at you? Does it spit back like a wild monkey? Does it kick like a child being dragged to the shower? Does it curse like a rapper?


    Seriously... define act up. Does it hunt, does frequency or voltage vary? Does it shuts down?
  11. Capt J

    Capt J Senior Member

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    How much fuel do you have onboard?
  12. Dan balmer

    Dan balmer New Member

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    I have plenty of fuel aboard and have changed the filters. It runs fine until the engine room gets hot and then it surges and won’t run ac units. It acts like the voltage regulating device gets hot and stops working right. Is there some standard of air temp that should not be exceeded in a generator space? The manual says the temp should not exceed 104• F It sure feels like the ER is that hot or more especially when you slow down
  13. Pascal

    Pascal Senior Member

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    Engine rooms will usually get hotter than 104.

    Any error code on the AC control like low voltage?
    What voltage do you see on the voltmeter when it happens and what freq. engine rpm (surging) affects frequency first.

    I dont remember how the westerbekes are set up but it is possible for a voltsge regulator to b affceted bt heat
  14. wdrzal

    wdrzal Senior Member

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    This sounds like there is not enough sub-cooling after the condenser allowing the refrigerant to vaporize in the high side liquid line before it reaches the metering device.
    Last edited: Jun 8, 2018
  15. d_meister

    d_meister Member

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    Seems like you should try to find out if it's the generator engine that is surging due to engine fuel or controls issues, or if the engine is overloading from demands on the electrical end. Are there ammeters in the panel that could shed some light on the electrical demands?
  16. wdrzal

    wdrzal Senior Member

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    What refrigerant does your AC use ???
  17. Dan balmer

    Dan balmer New Member

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    Thanks for all the responses. I’ve gone ahead and changed the electronic controller board on the generator which I believe was getting warm and not working right. It was 18yrs old and 3400 hrs old. Anyway this solved the problem! I also installed a temp gauge in the engine room and pass on that the ER temp climbs to about 120 degrees after many hrs. Of running . This does seem high but the genset still ran well with the new board Was wondering whether the engines are ok with this and if something should be done on this 50’ 2000 yr Post with the MTU 8v183’s
  18. Capt J

    Capt J Senior Member

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    120 degrees is pretty darn hot. I would install larger blowers and find some way to keep the engine room cooler. You're definitely losing Horsepower and burning more fuel with the engines ingesting 120F air. If you try to open the engine room door at cruise, is there resistance or vacuum on it?
  19. Dan balmer

    Dan balmer New Member

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    Yes Capt j I agree it’s darn warm There is no vacuum of air at the engine access hatchway when opening or closing when under way The engines seem to be taking in air thru the large air box on the outside of each engine Hopefully that air is cooler than the air where the temp gage is located between the two engines in the alley near the ceiling. I tried running with the hatch open for a while like a half hour or so and the temp did not change on the thermometer. There is an accumulation of soot on the transom that has occurred from my last 3 trips offshore from around 75hrs of use and about 2000 gals of fuel This may not be normal but I don’t know I’m new to this boat and learning.
  20. Pascal

    Pascal Senior Member

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    Does it read 120 deg underway at speed or only after stopping or running slow? How far is the temp gauge from the engines?

    Underway at cruise engines usually pull in a lot of air which cools the ER and doesn't have much time to get hot. After you shut down or slow down to idle speed, temp will come up from the radiant heat of the engines and will often exceed 120F. Especially in a small sportfish whith a low ceiling

    Some soot is normal after such a time frame. Depends how bad is it.

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