A/C orientation in boat question ...

Discussion in 'Beard Marine Vendor Forum' started by Jennimar, Jul 26, 2020.

  1. Jennimar

    Jennimar New Member

    Feb 16, 2020
    1990 310 Sundancer
    Twin 5.7 Merc's
    We purchased our 1990 310 Sundancer around Labor Day last year, and it is Great (mostly). The A/C unit coninually has been freezing up after running for 10 to 12 hours. While running it blows cold and we have no issues, until the find for the coils freeze up.

    Had a few opinions from friends, but wanted a better source. The intake vent/filter comes from the main cabin under the front V-berth. The A/C unit is located under the V-berth, and the coils are on the side of the unit closest to the bow.

    My thought is that the unit was installed backwards and that the coils should be facing the vent opening (towards the main cabin). It seems to me that the return air needs to come from the main cabin, through the vent/filter, around the entire unit, and then reach the fins/coils.

    I have checked the water filter basket and the air filter in the cabin ... all clean there.

    Any thoughts on what the proper orientation of the A/C unit should be ?
  2. NotHerDecision

    NotHerDecision Well-Known Member PLATINUM Sponsor

    Jun 28, 2016
    Houston, Texas
    2001 Sea Ray 460 Sundancer
    2014 Seadoo 155 LTD
    2105 Seadoo 130 SE
    2013 Mercury Dinghy
    Cummins 6CTA 8.3L
    I agree with you but...

    you most likely have one of 2 issues.

    1. the refrigerant is low. You should have this checked.
    2. The fan is not working properly. (Recently I had a unit that wasn’t running on low speed)

    so. I would set the fan on the unit to run on high all the time and see if that corrects it. Then have the refrigerant checked before you turn the entire unit around and have to modify the water, drain, and air ducts.
  3. Creekwood

    Creekwood Well-Known Member GOLD Sponsor

    Apr 26, 2009
    Oakville and Georgian Bay, Ontario
    '97 330 Sundancer, Raymarine C80 suite with radar, Mercury 310 Hypalon w/8hp Yammie 2stk
    2X 454 carbs w/ vDrives
    I would think it should not matter how it is oriented since the air is drawn into the unit over the coils and then blows out through the ducting. Here is what Dometic suggests:

  4. PatSea

    PatSea Member

    Aug 9, 2008
    Lake Erie
    I have had icing of the coils a few times over the years. Each time it was on a very humid day and I had let the cabin door open enough that the load of humid air caused it to ice over. I set a fan on the coils for an hour or so, melted the ice and all was good.
    gasketguy likes this.
  5. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    2018 Back Cove 34
    Cummins QSB 6.7 480
    The orientation doesn't really matter much relative to airflow. The more determining factors are how to route the air lines and water hoses. The air is going to get into the system so long as there is an unrestricted supply.

    As an example I have 2 AC units on my helm deck, port and starboard, each mounted inside the bulkheads. There's an intake grille with a filter - then no ducting at all. The system will pull in air through the grill and it gets sucked into the fan. Both AC units are mounted the same direction. That means one has the air intake facing in, the other is facing out. They both work fine.
    Tacoma290 likes this.
  6. Korkie

    Korkie Active Member GOLD Sponsor

    Feb 2, 2016
    Leonardtown, MD Potomac River / Chesapeake Bay
    340 Sundancer 2006, Garmin 7612, xHD Radome
    Merc 496 Mags
    Bravo III Drives
    Had same issue with freezing up. A/C unit in same place on our 340 with coils facing aft. When we had freeze up issues, it always came back to fresh air restriction. Usually from putting the Yeti we have on the floor in front of the birth being too close. We keep it at least 8 inches out from the air inlet and so far so good. We do keep a hair dryer handy if it does re occur.
  7. BlueYonder

    BlueYonder Active Member

    Jan 12, 2015
    Chesapeake Bay
    QSC 8.3 600
    Some marine A/C units have an automatic de ice mode that can be enabled. Check your thermostat manual to see if it has one. Where is your thermostat located? Sometimes a remote temperature sensor need to be installed at the return air grill because the thermostat is in too warm of a location (direct sunlight, too close to the hull, etc.)
    gasketguy likes this.
  8. Jennimar

    Jennimar New Member

    Feb 16, 2020
    1990 310 Sundancer
    Twin 5.7 Merc's
    Thank you all for your responses. Going to check a few of your suggestions and see what can be done
  9. Express 390

    Express 390 Active Member GOLD Sponsor

    Sep 14, 2018
    South Shore of Long Island NY
    1986 SeaRay 390 EC
    1993 SeaRay 290 DA single 7.4 /Bravo 2
    1992 SeaRay 230 DA 4.3LX Alfa drive
    Twin 454 Crusaders inboards 4 blades
    Another reason for icing up is an improper charge if the pressure is too low it will cause an icing condition
  10. Jennimar

    Jennimar New Member

    Feb 16, 2020
    1990 310 Sundancer
    Twin 5.7 Merc's
    I went through everything and it all seemed correct. Took the advice that the cooling vents might have debris in them. Brushed out the cooling vents and vacuumed out that debris. Appeared to be quite a lot. After this cleaning, we have had no issues.

    Thank you everyone.
    Tacoma290 and Chris-380 like this.

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