Marine A/C Installed on 2120

I know there have been some posts regarding air conditioning solutions on 2120 and 2320's with portable units as well as roof mounted. I had been mulling over options for quite some time and finally decided to install a true marine water cooled unit, so wanted to share my solution for any others also considering this option.

-Installed Webasto 5000 Btu reverse cycle unit
-Had previously installed shore power, A/C panel, and inverter for powering while underway

A shelf was built behind the helm out of oak planks and starboard to support the unit. I installed two vents: one at the top of the helm to direct air upwards, and then another on the side that may be rotated either front towards the cuddy or aft. The electrical control box is mounted underneath (and out of sight) on the bottom of the shelf. Two above the water through hull fittings were installed for the water discharge and the other for the drip pan. For now, I installed a relay on the water pump output of the A/C and plumbed the livewell pump to supply water (thus avoiding another sea cock and hole in the bottom of the hull). So far this solution has worked flawless, but I may install the included water pump with new pickup at a later date.

Tried it out this weekend with air temp of 85 degrees and 80% humidity. Within 30 minutes had the cabin cooled by 10 degrees to 75, and then another 30 minutes down to 70 degrees. Running off the inverter and my house bank of two 100 amp-hour batteries the unit ran for approximately 2 hours before the inverter shut down. Running the unit while underway and the engine on, I had no problem keeping the unit going off the inverter continuously. Obviously, for longer stays at anchor will need to bring the portable generator.

Works great and hope this helps any others who may want to do this as well

Chris

That is so cool!!! I don't know if you read my post/project on a portable AC? I just returned the first unit a got another one (different brand) to try and get thru this season. I purchased the protection plan on them so the return/repurchase has not been a financial beating. I have resolved to just do what you have and instal shore power and a marine AC system. The portables just don't cool very well. Seemed like a good/cheap option at the time. Maybe this new one will do a little better? I've been looking at that same system you installed too. Didn't think about installing it under the dash though. Never thought it would fit there. I was thinking about building a custom cabinet that would fit behind the helm and that area with the starboard storage by the helm. Thought about running the intake water line across the fuel tank and thru the side of the copit floor?? I read the inlet needs to be a continuous uphill run to the unit? Also wondered about running the unit on the inverter while underway. I have so many questions. Can you take some pics of your inverter/battery and pump install? Also where you put the shore power inlet? Curious how the 5000BTU unit performs for you this summer? I'm planning on taking on these projects between December and March in the off season. I just finished up tabs/nav lights and VHF antenna & mount and my plan is to play/fish the rest of the season. I hope you don't mind me picking you brain on this stuff but you are one of a few who have attempted this set up. Again, very nice job and good luck! 8)

My only question is why did you use plastic thru hulls? The Sun eats them up. I've seen them so bad the head popped off of one.

You want 316 series Stainless above the waterline.

Shawnee,

Thanks for the reply. I actually did see your post on the portable unit, and after hearing some of the feedback on those helped sway me towards the marine unit. I like the idea of building a box behind the helm chair and running the water line above the fuel tank. You are correct in that the supply line should run steadily up hill (no dips to avoid issues priming the pump I think). It does fit behind the helm like I did, however it is a very tight squeeze. The other obvious issue is the need to move the unit out of the way to access wiring or any maintenance behind the helm. On the plus side, it is completely out of sight, allows for some air vents mid cabin, and also allows for a downhill run to the overboard discharge. I wonder if that might be an issue with a box behind the helm depending how you plan to route the discharge? I am out of town but will take some pictures of plumbing set up as well as batteries/inverter.

Warthog, completely agree with the stainless through hulls however the plastic fittings are what came with the AC installation kit. I was excited to install the unit and did not want to wait on ordering new fittings. Will probably replace in the future with SS type.

I have been thinking of putting a marine A.C. in my 2120. Under the bench seat I was going to remove the tackle box & mount A.C. unit inside. Also put a divider between that area & the storage area. Hinge the top of the bench seat for access
and go from there. The unit would be mounted high enough for drain & feed lines. I will keep an eye on your posts and see if you are pleased with your job. My concern is to much weight on the starboard side of boat.

Best of Luck

" Bean "

Thanks TTucker for the reply. My plan for the condensation ,if mounting behind the helm chair, was to use a sealed shower sump to pump the water back up to a side drain similar to yours. To be honest, it's all just been in the rough draft stage, brainstorming. I have the older style dash so it may help some with fitting it there? I've been looking at the Marine Air 6K BTU unit and your Wabasto. I really like your dash mount as it solves several issues (plumbing, fabricating storage unit to mount...)and it uses space I won't miss. I hear ya about the wire access though. I'm going to take some measurements next time I'm at my boat. I look forward to seeing your pics and talking with you about these projects. The more I look at yours the more I like the concept.

Attached are the photos for my shore power inlet installation, battery bank, and inverter set up. I have both a 15 amp and 30 amp inlet connection - on the back (interior) side they are behind the plastic wire run cover and are completely hidden. Battery bank is stock, except added an additional battery in parallel (both 100 amp-hour AGM batteries) with in-line breaker straight to Xantrex inverter, with remote control in cabin. Inverter is a tight fit but was able to mount neatly in front of the batteries with only an 18" cable run from battery terminals.

Happy to report A/C is still working great and functioning fine off cooling water supplied by livewell pump. Did notice a little extra weight that Bean mentioned, however this has somewhat been mitigated by the additional house battery on the port side. When the wife & dog are along they sit on the port side and everything is balanced great. When its just me the boat has a slight starboard lean that i just level out with the tabs - has not been overly noticeable so far. I will note that after a couple hours with the inverter running the A/C and engine running, I did notice the voltage start to dip into the 12's (alternator was not keeping up with the load). Did fine for almost 3 hours running before I noticed the low voltage, so something to think about for those wanting to run this while underway. I might have to start running off the portable generator if going to be out for longer and running the A/C.

Tucker, your installs are very nice. I'm having trouble figuring out the orientation on the battery box's? Is the inverter and 2 batteries on the port side? Do you have a newer model 2120 with the live well built into the transum? I know the jump seats/boxes are bigger on the new 2120's. I thought that you mounted the extra house battery on that shelf in the bilge? What motor do you have? My 06 F225 has a 45amp altanator I think? I thought the new 225/250's have a 65amp? Anyway, I think that would be about what you would need to about break even with the draw while running your AC on the inverter? Again, great set up. All stuff I want to do to mine.

Shawnee, I've got the newer model with the built in live well. I think the space under the back seats may be bigger than yours as I do not have the shelf in the bilge. From the factory, mine came with two batteries, one under each seat. Now I have 1 starting battery on starboard side and 2 house batteries on port side underneath the jump seat (they run the length of the boat, so front to back). Seems to be a good set up but it is very tight on space with two batteries and an inverter in that compartment! Have you thought about building some sort of box to house additional batteries if they won't fit under the seats?

My motor is the new 175 HP model (2.8 liter block) and has the 50 amp alternator. (really need a larger 65 or 75 amp to maintain the load of the AC/inverter more than a couple hours) What I've ended up doing is strapping my Yamaha 2000i portable generator to the roof and just running that all day...has been great keeping the AC running as well as battery charger going when we are anchored. Of course have to be careful of the CO fumes when anchored, so we make sure to just run off inverter as much as possible and when winds are light.

AC still working great with this set up and no complaints. I am still using the livewell pump to supply water to it without any issues. Was 85 deg outside last weekend and unit kept the cabin a comfy 72 and compressor was even cycling off occasionally (5k Btu has ended up being adequate with outside temps below 90, above that and it just runs constantly)

Make sure u put a carbon monoxide alarm in cabin if u are gonna run genny off roof. Just mt 2 cents.

Tucker, I hope you still check this. Anyway, what size inverter did you install?

Hey Shawnee,

I installed a Xantrex Pro 2000 watt inverter. It started the AC unit no problem and runs pretty much anything I needed (microwave etc) since it is pure sine wave power. I would not use anything smaller than a 1500 watt unit if trying to start and run an AC unit.

Tucker, was it the Prowatt SW 2000? It appears to only have GFI connection but not hard wire option? Did you hard wire it to the panel or make a plug and wire to the panel? Thanks.

Sorry, yes Prowatt SW 2000 was the one I used. That particular model did not have a hardware option so I added a plug (from local hardware store) to some 12 gauge marine wire and ran that to my AC input selector and from there to the panel. They may some models with a hardwire option, but that was not a deal breaker since it was easy to just add a plug and those units (hard wired) tend to be a little more pricey.