![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/IMG_7117.jpg\")
The forward unit, a 6,500 BTU Dometic unit was very easy to get at, located in the back of a roomy forward hanging locker.\u00a0 Getting to the unit was very simple and yet the installation still took the tech nearly two days.<\/p>\nI’ll be truthful when I say that we hardly ever use our AC, especially in the Caribbean where there are constant cooling breezes.\u00a0 However, in New England and the Chesapeake, where the breezes die at night, that’s a different story.<\/p>\n
On the rare occasion that we tie up in a marina, even in the Caribbean, we use our AC to stay cool.\u00a0 \u00a0 The problem, even in trade winds, is that in a marina, we are generally not facing directly into the breeze so getting sufficient air below can be a problem.<\/p>\n
When we found ourselves in the midst of pandemic lock-down in St Lucia last winter we fired up the AC units only to find that both units were just blowing hot air as they had lost their coolant charge.\u00a0 We contacted a tech who quickly recharged them both and cool we were again.<\/p>\n
Unfortunately, that “repair” was only short lived and when we arrived in Florida, following our run home to the US, both units were again low on coolant.<\/p>\n
I contacted a local tech that declared both units dead and recommended that they be replaced.\u00a0 His opinion, after making a service call of course, was that it never made sense to try and repair what he referred to as “package units”, those units where the entire system is housed in a single “package”.\u00a0 \u00a0He went on to say that the life expectancy was about 7-8 years.\u00a0 So, I guess that Pandora’s units, now more than a dozen years old, were well overdue.<\/p>\n
This is the front unit after it was removed, and it sure looked ready for the scrap heap.\u00a0 Note all the rust in the drip pan.\u00a0 \u00a0I had the forward unit replaced by a tech in FL, but replaced the aft unit myself while Pandora was in Annapolis.\u00a0 It was surprisingly easy although I did have a tech hook up the unit and check that it was running properly. The forward unit, a 6,500 BTU Dometic unit was very easy to get at, located in the back of a roomy forward hanging locker.\u00a0 Getting to the unit was very simple and yet the installation still took the tech nearly two days.<\/p>\n
The new unit, also the same 6,500 BTU output, but with a stronger blower, is much improved and works beautifully.\u00a0 ![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/dometic-6500-btu.jpeg\")
One issue with any AC unit is that they give off a lot of water that drips off of the condenser and can add up to several gallons per day, per unit.\u00a0 \u00a0Normally, this water drains into the bilge, which isn’t ideal.\u00a0 In this case, the tech recommended that I add a special positive drainage device that installs into the cooling water exit line.\u00a0 It is the grey unit with the red arrow.\u00a0 It also has a small strainer to the right to be sure that nothing can be sucked into the unit and block the tiny exit hole.\u00a0![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/IMG_20200716_124012181_PORTRAITa.jpg\")
The principle behind this active condensate drain is that when the water is forced through the narrow part of the fitting, it passes a small hole on the bottom, causing a vacuum that sucks out the condensate and evacuates it overboard as part of the cooling water.\u00a0 \u00a0The suction is caused by the venturi principle where a fluid is passed horizontally, constricted as it passes a hole, causing the formation of a vacuum. ![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/300px-Venturi5.svg_.png\")
It’s a simple, elegant approach and works very well.\u00a0 I installed one on both units.\u00a0 I’d put in a link but could not find one on the Dometic site.<\/p>\n
The aft 16,000 BTU Dometic unit had never cooled the main cabin effectively and after analyzing the installation, we determined that the two ducts that were part of the original installation, did not allow for sufficient air flow over the condenser and therefore caused the unit to ice up and further restrict air flow.\u00a0 We were never able to get the main cabin down below the high 80s.\u00a0 The prior owner told me that the unit was just too small for the boat.\u00a0 However, with modifications, this hypothesis proved to be incorrect.\u00a0 It was simply a badly designed installation.<\/p>\n
After thinking about the problem, the simple answer was greater airflow, the addition of a third vent.\u00a0 \u00a0The fix was simple, well simple in concept, as I had to install a new duct that went through the top of several lockers, using a 5.5″ hole saw, intimidating to use as it creates a lot of torque as it bites into the bulkhead.\u00a0 \u00a0![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/hole-saw.jpg\")
I’ll admit that I really took a deep breath when I started to cut that 12″ square hole in a cherry bulkhead, but it turned out well.\u00a0 ![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/IMG_20200909_145905313.jpg\")
What a difference it\u00a0 the extra air flow has made and basically doubled the cooling capacity of the system.\u00a0 The original ducts included a 4″ duct with a very long run, in the main cabin and a 3″ vent in the aft cabin.\u00a0 \u00a0 It was not practical to change the main cabin duct but I upgraded the aft cabin duct to 4″ and the new duct in the galley at\u00a0 5″, allowed for a substantial increase in capacity, matched to the system.<\/p>\n
Adding air flow capacity to the system was doubly important as the new unit has a larger blower with greater flow.\u00a0 Now we get 60 degree air blowing right into the galley, where it is needed most. I also split the forward unit so that I could divert some of the cold air from the forward cabin back to the main cabin.\u00a0 That involved putting in a small 4″ louvered vent on the bulkhead adjacent to the unit in the forward locker.\u00a0 That was fairly simple and it is set up in a way so I can close it and divert all of the air into the forward cabin as needed.\u00a0 It is a nice edition and blows cold air over the starboard settee, the hottest part of the main cabin.![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/IMG_20200909_145846546.jpg\")
The unfortunate reality is that we had not been able to use our AC at all at anchor as Pandora does not have a built in generator.\u00a0 As I mentioned, previously, we have not felt a need to use the AC at anchor, when there is a breeze, but summers in the Chesapeake or New England, south of Maine can be stifling at night when the breeze dies.<\/p>\n
With 600 watts of solar we have never felt the need to have yet another complex and EXPENSIVE piece of equipment on board and many of my friends with generators have reported plenty of maintenance issues, especially if they don’t use the generators regularly.\u00a0 And, to spend $20k+ to put in a generator and add all that weight to the boat when we won’t be using it much, doesn’t seem prudent.<\/p>\n
Once the 16,000 BTU unit is running it doesn’t draw all that much power and the small Honda 2000 gas generator can handle it.\u00a0 However, when the compressor starts, the draw causes too much of a amp spike and causes the generator to surge, tripping the fuse every time.<\/p>\n
![\"\"](\"http:\/\/www.sailpandora.com\/wp-content\/uploads\/2020\/09\/soft-start.jpg\")
I understand that the Easy Start’s magic is that it “learns” the momentary peak draw of the starting compressor and somehow smooths out the load so the generator is not hit with a sudden jolt.<\/p>\n