Air replacement.

What do you have now? I would replace it with same brand......either cruiseair or Marineair (both owned by Dometic). Do you have a split system or package unit (everything in one)? I'd stay with the same BTU's if the previous unit cooled well enough......go larger if you had cooling issues before and have the room and power for it.

They still make split units, look on Dometics website it has the list price on there as well. The package units are easy to install but don't seem to have the lifespan of the split units. I would replace with Cruiseair, you're probably going to have to replace the display/control which is additional.

I would get in contact with a few good a/c guys in your area and get quotes. The copper lines on the split system are going to need to be brazed, vaccuumed down, and charged. Need to check what voltage your units are etc. and going to have to update to new controls. The SMX II display usually fits in the same place as the old 3 button knob ones.

FWIW, I think self-contained units are simpler. Many of our owners club members have replaced aging units with Dometic "Vector Turbo" units and say their better (cooler, quieter, easier install), no rust from condensate, and in many cases they've been able to re-use existing control panels. (I suspect that's not likely with 36-year0old controls, though. It'd work for our 14-year-old units.)

Not a recommendation, just observations and thoughts...

-Chris

At 36 years old, I wouldn't spend a dime on the old units.

The self contains do cool very well. I manage one yacht that has 6 of them, we replaced one 2 years ago with a new R 410A marine air 16k btu and the temperature coming out of the vent is 34F, that one had a compressor failure at only 7 years old . We just replaced 2 more out of the 6, 1 was shot, coils disintegrated, the other was working ok but not large enough for the area, but the steel pan was getting to be in poor shape.

Pascal, I'm not a fan of chillers in your size boat for several reasons. It takes a lot more energy to run 1 chiller sized for the whole boat, (better have a 2nd chiller too) if you just want to cool off 1 stateroom or the salon. Or if you lose shorepower, it takes a good while to get the loop temp down AND cool off the entire boat with chillers. Even with soft start compressors, you're burning a lot of amps to have the unit cycle on and off, just if 1 a/c is calling for cooling. They also tend to always have a chilled water leak somewhere and always have to add water to them it seems........ And my biggest gripe is either the entire boat has a/c or heat, not both.

Don't forget in South Florida all of the chilled water lines should have 1" thick insulation around them, so that makes routing them a royal treat on a retrofit. You'll never find the coolant leaks usually, as a lot of times it's a drip or two here and there etc. etc. Is it coolant or is it just sweating etc. etc.

Condensation and Coolant should have one crucial difference- Coolant should have an antifreeze in it which in my experience adds colour to the water which makes the drips easy to identify

Is start-up surge really a big deal? Neither of ours trips a breaker...

FWIW, there's some kind of control in our overall system somewhere so both units (shared pump) won't start at the same time; don't know where that is or what it looks like, but at least we never see 2x (simultaneous) start-up surge...

Another FWIW: When I opine that a self-contained system is simpler, that's partly influenced by having two of 'em in place now... so that, for us, a one-for-one replacement could be very quick and easy, re-use plumbing, etc. Replacing one of our current systems with a split would be more work. Perhaps easier to replace a split with a split -- if that's the starting point anyway?

-Chris

A package unit is easy because you just hook up electric, the water lines and the controller and it's ready to go. Usually the new package units aren't much bigger than the split air handler you have now.

A split is more work even though you have one because you have to remove and mount 2 units (compressor and air handler) and also because you have to braze (weld) both copper freon lines at the air handler and compressor unit, then vaccuum them down, then add freon till you get to the right amount. But if you have a split, usually you replace with a split.

Yeah, I'm aware of that. Beard recommends I think it's a 15% Glycol mixture, but have seen green, but either the blue/red/ or green is pretty faint color at a 10% mixture. A faint blue drip in a bilge that has dark grey bilge coat can be pretty hard to notice sometimes.

Retrofitting a yacht under 75' with chillers can be a complete nightmare, you're running 2 1" hoses throughout the boat that are covered with 1" thick insulation, so all in all about a 3" hose. I've done them before. Yes you can get them so they don't drip/condensate but routing them in a retrofit of a yacht that size can be a nightmare through bulk heads and everything else.

I've had to redo Neptunus' insulation on a few of their yachts I managed because Neptunus being in Canada used only 1/2" insulation on the chilled water lines and when the yachts get to be at about the 5 year mark, the lines start condensating everywhere, a lot of them in places you can't really get to, but in the bilge so the dripping isn't damaging anything, just losing cooling efficiency.

Of all the yachts I managed with chillers and under 75', I've had to periodically add water to the chilled water loop on ALL of them, including a yacht thats a 2013 that I manage right now and a 2015 that I run North and South.

Do you bother to check and see where the leak is before adding coolant to the systems?