Adding a second Air Conditioning Unit to 350 Mariner

[Bryon857]

I am thinking about adding a second AC unit in my 350 Mariner. Has anyone done this? I know the second AC was a factory option, can someone send pics of unit under dinette? What size are the in and out ducts? Thanks for any info you may have.

[Bryon857]

Also, is there one water pump or two on a factory setup? What size is the pump, 500 gph?

[km1125]

How big is the existing unit? I would think 500 GPH should handle two units without a problem.

If you need ducting, let me know. I just picked up a variety of surplus parts from one of the local installers who retired I have 2, 4 and 6" flex and a whole bunch of various colored 4" grill/registers and a several other parts. When you get your list together let me know.

[Bryon857]

The existing one is 16000 btu. Thanks will contact you when I decide what to do.

[Midnightsun]

I can highly recommend the MarinAire brand which I have retrofitted in no less than my last 2 boats and have on hand 3 new units to retro fit Midnight Sun this summer as the originals are rather noisy and inefficient. MarinAire is not to be confused with Marine Air as many do. The units I have had were extremely quiet, so quiet that if you stare the unit in the face and wait for the compressor to kick in, you will be hard pressed to hear it, no kidding. They use Toshiba compressors which are arguably the best in the industry. Larger units come with diagnostic gauges built in and the price is surprisingly low not to mention service when you call is next to none. See here. https://www.marinaire.com

[CaptBob]

I will add a +1 to the MarinAire People. I installed one in the Salon for this winters project (that stretched into the spring) . After a fair amount of research, I wanted a quiet unit, and it is. Very quiet, and the AMP draw is very low. Genny doesn't even notice when it kicks on. Problem is, now I hear just how much noise the lower unit makes.

Watch the water flow. A 16K unit calls for 400 GPH. My 14 year old pump at a 1000 GPH (at 3 feet of head) I feel is struggling to supply both units. I suspect it is time to upgrade/replace that also. Grrrr it's a never ending cycle.

ac-install.jpg

I was messy for a while, some trimming (cutting) involved, I had to space the ice maker out about an inch with some black starboard to gain some room for lines behind it...

[DesertX]

I have a 2001 350 Mariner with the factory second AC option. Both units run from the same water pump. Here is a picture of the second unit under the dinette seat nearest the kitchen.

P1020557.jpg

[bud37]

Qr Bbpost Watch the water flow. A 16K unit calls for 400 GPH. My 14 year old pump at a 1000 GPH (at 3 feet of head) I feel is struggling to supply both units. I suspect it is time to upgrade/replace that also. Grrrr it's a never ending cycle.

You could measure your water flow to check...timed 1 gallon, then a little math will give you the flow now...

[Bryon857]

Thanks everyone for you knowledge. I think am going to check airflow on my 16000 unit, I am thinking my evaporator is dirty. I am fairly sure it has never been cleaned.

[CaptBob]

Qr Bbpost
You could measure your water flow to check...timed 1 gallon, then a little math will give you the flow now...

Math is hard. I'm looking for a 1000 gallon tank, and just let it run for an hour.


On the realistic side, the pump splits into to two lines just past the pump. The upper unit outflow hose runs all the way to the stern and exits there. The unit under the bed exits in a thru hull in the bow. I can access the upper's return line before it exits (under the swim platform, right near water lever) pull it, put it in my 1000 gallon tank, (might get 500 and only have to multiply x 2 ) and see what it's doing.