Marine Air Heat Pump Install

I spent 6 months considering all of the options and configurations that were available before I finally purchased and installed the system.  I did the whole installation myself and it went very smoothly.  I looked at Aqua Air (http://www.aquaair.com/), Cruisair (http://www.cruisair.com/) (located in my home town of Richmond, VA and recently acquired by Marine Air), Marine Air (http://www.marineair.com/) and Mermaid Air (http://www.mmair.com/).  I considered both self-contained and split systems.

I choose a Marine Air Vector Compact 16,000 BTU reverse cycle unit that I purchased from Ocean Options (http://www.oceanoptions.com/).  This is not the same unit as the Marine Air Cabin Mate (a retail kit) sold through places like West Marine and Boat/US.  The components used for both are pretty much the same, but the orientation of discharges are different and the over all cubic inches of space required was less for the Vector Compact.  I ended up spending a little more going this route than using a Cabin Mate, but it suited my needs better.  The 16,000 BTU rating could be considered over kill for an IP31, but for the little bit extra in cost, I have a unit that can handle the hottest days and perform the initial cool down much quicker.

I installed the unit under my v-berth, with the air discharging to my port side (the IP31 layout is the reverse of the IP32).  From the unit I lead a 6 inch duct to a Y.  From the Y for the forward cabin, I lead a 4 inch duct to a discharge grill mounted through the side of the hanging locker.  From the other side of the Y for the main saloon, I lead a 6 inch duct to a discharge grill mounted in the side of the other hanging locker.  The return air for the unit flows through the two louvered doors that serviced the cabinet space under the v-berth.  It is best to have the shortest duct runs possible with the fewest angles.

For electrical service, I ran 10 gauge 3 conductor wire down the starboard side behind the deck/headliner flange.  I installed a dedicated 20 amp breaker at the nav station to service the unit.  For the control head I replaced the flat silver satin cable with a twisted pair cable as it runs parallel to the power cable for the entire length and did not want to have to worry about electrical interference.

My water intake is through a speed scoop/thru-hole I located in the bottom of the port side cabinet under the v-berth, the thru-hole for water discharge is just forward of this and located about 8 inches above the water line.  It is very important to take in to account the relative levels of each device.  I followed the mounting instructions provided at http://www.marineair.com/manuals/vector_compact/ to the T.  The only deviation I did was to drain my condensate pan to the bilge.  This is not normally recommended as bilge vapors could get sucked through this and then discharged into the air via the unit.  I overcame this by running the discharge hose through a hole in the bottom of the locker.  The hole is the same size as the hose so provides a tight seal when inserted.  I then created a water trap (similar to what you would find under a standard sink) for the apor block.  Another option that Mermaid Air sells is passive device (http://www.mmair.com/cond/cond.html) that connects to the discharge line that sucks out the condensate.  I will probably go back and retrofit one of these and see how well it does, but for now this setup works well.  I will also remove the unit this spring to paint the interior of the locker and may install some sound dampening material.  Other needs include installing longer tailpieces to the raw water fittings to allow for double clamping.