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HVAC placement

Discussion in 'Technical Discussion' started by ArielM, Jul 28, 2011.

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  1. ArielM, Jul 28, 2011
    #1
    ArielM

    ArielM Senior Member

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    I have 4 split system AC units in the boat. (condensers in the engine room) about a month ago one of them went bad and i had to take the condenser out of the boat. I got a smoking deal on a single unit (condenser and evaporator coil in one). Now i was thinking to place this new unit in the bedroom and simply run raw water hose from the engine room to the master bedroom (drainage as well). The only problem i have with this plan is the raw water hose will be about 15-18 feet from the raw water pump. Considering all the condensers are in the engine room, will enough water reach this new unit in the bedroom? Elevation of engine room and bedroom are roughly the same.

    NOw if this idea wont work can't i simply disassemble the unit and make it split system? as long as i place the air handler in another location and connect with copper lines it should work no?

    Any input would be great.
  2. Capt Bill11, Jul 28, 2011
    #2
    Capt Bill11

    Capt Bill11 Senior Member

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    With the right pump and plumbed correctly it should work fine.
  3. Capt J, Jul 29, 2011
    #3
    Capt J

    Capt J Senior Member

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    Correct, I agree with Bill. What you want to see is a manifold thats say 1" going to say 1/2" hoses going to each unit. That should supply enough backpressure on the manifold so that all of the units get waterflow.
  4. ArielM, Jul 29, 2011
    #4
    ArielM

    ArielM Senior Member

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    I will check it out tomorrow.

    What if i put the self contained unit in the engine room and placed a duct from engine room to unit? I guess i might have carbon monoxide issue IF there is a leak in engine room.
  5. Capt J, Jul 29, 2011
    #5
    Capt J

    Capt J Senior Member

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    Do not do this.

    You shouldn't have issues with water flow, providing your pump is large enough to pump enough seawater for all 4 units to start with.
  6. Bill106, Jul 29, 2011
    #6
    Bill106

    Bill106 Senior Member

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    Unless you also duct (with insulation) the return air to the air handler, you do not want to do this. Besides the potential monoxide issue, an average AC unit will only change the temp of the air moving across the coils by ten degrees or thereabouts.

    You didn't mention what type of seawater plumbing you have, single pump with manifold or multiple pumps. If the elevations at both locations are about equal, either should work fine. Hopefully it is a newer unit with refrigerant gas alarms so if there is a lack of seawater it will tell you in short order.
  7. ArielM, Jul 29, 2011
    #7
    ArielM

    ArielM Senior Member

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    ya i was thinking about it and the risk of carbon monoxide and differential of heat in engine room kills the idea real quick.

    The pump is designed to provide water for 4 units. There is a manifold. I just thought that maybe because this unit would be farther away most of the water would flow to the 3 units in engine room.

    My only real problem with putting this unit in the engine room is that it will be noisy.

    A split system and self contained unit all have the same parts. Does anyone see a reason why i can't splice the Hi and low side and split the unit? Put the condenser in ER and the evap coil in master bedroom? Then i can use the original copper lines. what do you guys think about this strategy?
  8. Marmot, Jul 29, 2011
    #8
    Marmot

    Marmot Senior Member

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    Not necessarily. What unit is it, how old is it, what refrigerant, does it use an expansion valve or a capillary tube?
  9. Pascal, Jul 29, 2011
    #9
    Pascal

    Pascal Senior Member

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    Any spare sea cock you can reuse close to the master ? Small Pumps are cheap and redundancy is always nice

    That could be a big difference in back pressure between the ER and the 18' hose, easy to hook up the hose before making a decision and see how much flow you have
  10. ArielM, Jul 29, 2011
    #10
    ArielM

    ArielM Senior Member

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    unit is probably a few years old. capillary action evap coil and R22 freon.

    There are obviously two lines going into the evap coil which is where i would splice it at. i would have to solider on some pressure fittings.

    Only question i have is that the hi pressure and low pressue copper tubes are both the same size. i guess it is because the unit is so small and all lines are no more then a 1.5 feet long.

    btw it is a mermaid 9000 btu self contained unit with reverse cycle.
  11. Bill106, Jul 29, 2011
    #11
    Bill106

    Bill106 Senior Member

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    Many of the newer units have an optional compressor sound shield that helps a lot with the noise issue. If that unit has one available, spend the extra $100 or so and add it while your doing the install. If it doesn't, you can always add some insulation in the compartment around the unit but use marine not household type, which can shed fibers and clog the vanes in the evap.
  12. Marmot, Jul 29, 2011
    #12
    Marmot

    Marmot Senior Member

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    I think a visit to a local marine air conditioning specialist is in order.
  13. CaptPKilbride, Jul 29, 2011
    #13
    CaptPKilbride

    CaptPKilbride Senior Member

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    Quite possibly the "smoking deal" mentioned in the original post isnt looking so great with all the added headache?
  14. wdrzal, Jul 30, 2011
    #14
    wdrzal

    wdrzal Senior Member

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    Not knowing the compressor type here's some things to think about:

    Hermetic rotary & scroll compressors reject from 5% to 15% of their "heat of compression" through their shells. If this heat is not vented the compressor will overheat and shut down or eventually burn out. They need airflow over the compressor.

    Only hermitic reciprocating compressors can be 100% suction cooled. (heat rejected out the heat exchanger/condenser).
  15. ArielM, Jul 30, 2011
    #15
    ArielM

    ArielM Senior Member

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    This compressor has an optional sound shield that can go over the compressor to reduce noise so i am sure it doesnt need ambient air flow over the unit for cooling.