AC questions

I’m not directly answering your questions but on my boat on hot days (not hot by FL standards mind you) I put a small fan in the door of my master strm blowing down the passageway and up the stairs to the salon. My staterooms gets much cooler than the salon and moving that air up and around seems to really help. Especially since the cold air is going to naturally settle downstairs and heat will rise anyway.

The freon type should be on the nomenclature plate on the units, but you probably won't get it at an auto parts store. You'll need a set of gauges to add freon.

It’s not just the outside temp but the water temp as well. If you re on a canal or closed basin chances are the water is hotter than it would be in a larger body of water.

we re having a big issue in sofl with small
Mussel shells growing in the hoses. This summer has been a real struggle. They restrict the water flow causing the units to run hot and in some cases tripping on high pressure. Descaling helps.

if your units are cooling why would you want to add “Freon” ? If the pressure isn’t right, they will trip

and if they are working, why do you want to replace them? Assuming you have self contained and not remote condensers, a 16k BTU will about $3k. Oh and yes the older units were better built than the new ones…

as to brands, I consider Dometic to be the evil empire of the boating world. They ve gobbled up dozens of food brands and either merged them or eliminated them altogether. All their units whether self contained, splits or chillers use expensive proprietary electronics control boards.

5 years ago I installed a chiller system on my personal boat to replace the old remote condensers aka splits. I picked Flagship Marine in Stuart fl. All MADE IN AMERICA, which designed and built. No fancy electronic, they use off the shelf parts and thermostats. They also make self contained and splits.

in fact I have already replaced 6 failing Dometic Cruisair air handlers on the 110 I run with flagship air handlers. In all fairness they were 2005 vintage so I can’t complain. I just prefer the simplicity of the flagship and their solos construction

but again, no need to replace yours if they work.

Like Capt. Ralph wrote; you probably have R-22 units but that gas is many years out of production and even if you found an AC guy with some you best be sitting when you hear the cost of it. That said; before adding any you need to put pressure gauges on to see if it's even low. My 3 units, including blowers were replaced last year and I found the new blowers from Dometic do a much better job and even on the hottest S. Florida days the boat stays nice and cool. On my previous smaller spt. fish with only 2 units I had the forward salon windshield glassed and that made a huge difference.

@RossC

Nature of the beast, yep.

You've seen external covers -- mesh, Sunbrella, Stamoid, etc. -- can help. Another you might consider in the longer term is interior window tinting, with a product designed for IR/UV filtering. (FWIW, we used 3M Prestige 50 on the front windshield and it makes a good difference. We used Prestige 60 on the rear slider, don't get as much sun there anyway so can't tell degree of difference. Neither obscures our vision outward, and neither is "privacy" tinting. We're now thinking of adding the same tint to some of the side windows.)

Flushing your system with dockwater can sometimes help. Water pressure will force water straight through and overboard... although I think the outcome isn't too much different than running the system on raw water with your existing pump. Still, it's clean water...

Flushing the raw water circulation system with either Barnacle Buster or Rydlyme can work. Both products recommend constant recirculation for best results, but... that's not so easy to do with the boat in the water. Still, I've used the "fill, wait, add more, repeat..." approach with Barnacle Buster and it works reasonably well. A small transfer pump will push solution right through your onboard pump, so it's not too difficult to add a gallon, wait, add another gallon, wait, etc. (Even better in our case would be a valve'd manifold so we could better control flow especially through our "farthest" (bow stateroom) unit... and the valves are on my To Do list.)

We've replaced a couple Marine Airrrrr Vector Compact units and one Cruisair Stowaway unit (so far) with Dometic units that are now called DTGs (descendant from the Marine Airrrr Vector Turbo) and they've been a great improvement. Better air flow, better (composite) drain pan, better cooling overall and worked with our pre-existing control panels (Passport II on the previous boat, SMXir on this one) although maybe we had to order the right unit to get that compatibility. (Can't remember.) Best to order at a time when you can get "boat show pricing" discounts.

The CTM units, same footprint, are said to be ditto all that... including working with existing control panels, and so far estimates tend to be slightly less expensive than the Dometic units. I've read their delivery packaging is sometimes challenged, but also that if the units survive transport everything else is good. As our remaining 16/12K units age out, I'm considering trying CTM...

The original bridge unit on this current boat was delivered as a Cruisair 24K BTU model, don't know product number. We replaced it with a more current Dometic DCU 27-2361-410A unit... which was about an arm and a leg $$$ even with 20% discount... but seems to work OK. Not easy to cool the greenhouse; works better when we close the hatch to the bridge (which you might not have?).

-Chris

Barnacle buster works pretty well and it a not as corrosive and nasty as muriatic acid. Not familiar with Bright Bay.

the easiest way to do it is to get a bucket, a small bilge pump and the right size hose or fittings. Ideally you want to descale the hoses as well between the strainer and the units. Problem with self contained is that they are scattered all over the boat making it difficult to catch the outflow back into the bucket. If that’s not possible then you need to descale one by one

as a pump, I like the 120v rule 1800 as you can plug it anywhere and don’t have to worry about finding 12 volts. I always have one handy on board as a back up or for whatever emergency may arise.

back flushing with pressure water helps as well especially for the **** mussels I mentioned in my first reply. When they get dislodged they usually pile up at the coil inlet or in manifolds. In fact it’s been so bad this summer that I have rigged both my own boat and the 110 with valves and tees so I can just flip valves and back flush one chiller at a time when needed. Sometimes I get as much as 1/2 cup of shells out. No hoses to pull off fittings or anything.

air con techs charge around $200 per unit for descale… it adds up.

We upgraded our window tinting on the salon level 3-4 years ago. Has made a significant difference for us.

Forgot to include:

If you have Groco strainers, Trac (the Barnacle Buster people) offers a lid replacement that takes a garden hose attachment.

Or you can insert a Groco SSC with flush adapter somewhere in your system, either before or after the strainer.

-Chris