Boat heat and air system installations are a joke

Discussion in 'Modifications/Customizations' started by Carpediem44DB, Jan 2, 2022.

  1. Carpediem44DB

    Carpediem44DB Well-Known Member GOLD Sponsor

    Aug 18, 2015
    Sanfransico Bay area
    2000 Carver 506
    2006 44 DB Sedan Bridge
    Volvo TAMD 74 P
    This is the first winter we are enjoying on the 506. We have 6 heat and a/c units. The four cabin units are 16000 BTU Dometic units installed in large compartments under the beds or under lockers. The units are secured to the decking and a hole has been cut and filled with a louvered panel of some sort for the return air from the associated cabin and then the treated air is routed via flex ducting to a poorly placed but convenient outlet. It takes forever for the cabin to warm up from the high 40's to 70 degrees in the morning and then the system runs for quite a while when it cycles at the temp selected at the controller. Upon investigation since these units have no return air ducting, they take air in from the surrounding area and whatever comes in through the return vent on the cabin wall. Most of these areas however are unsealed and open to the cold air from outside the cabin area. There is just a simple dust collecting half ass filter at the heat exchanger to boot. I will be fabricating actual sealed return air ducts that will accept household air filters. I would love to plumb the system with better placement of outlet air vents as well but that would involve a lot of cabinetry removal and modification which is not worth it but I think recycling only the air in the cabins and not outside air will make the system much more efficient.
    Nater Potater likes this.
  2. Strecker25

    Strecker25 Well-Known Member PLATINUM Sponsor

    Nov 20, 2014
    Rochester, NY
    2002 410DA
    Caterpillar 350HP 3126
    i always thought the same. Our 410 only has two units and both are somewhat centrally located but they cycle often since the intake is just open to the room. It should have proper returns in a couple
    Locations and a properly located thermistat sensor. I set our fans to run constantly so the air or recirculated otherwise the temp swings are outrageous
    Nater Potater likes this.
  3. 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
    We have two units with the same poor air return designs... I leave the fan on a low-speed setting with no cycling and find I'm much more comfortable.
  4. Dani-Lu

    Dani-Lu Well-Known Member SILVER Sponsor

    Apr 20, 2007
    Delray Beach, Fl
    2001 410DA
    3126 Cats
    You can move the temp sensor probe to anywhere you choose. As you can see in the attached pic, I moved mine outside of the salon couch so it is sensing the air before it goes thru the air intake vent:
  5. Strecker25

    Strecker25 Well-Known Member PLATINUM Sponsor

    Nov 20, 2014
    Rochester, NY
    2002 410DA
    Caterpillar 350HP 3126
    i did move it in the old boat, considered it for this one as well. Do you find it keeps the cabin more even?

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