Marine Air Conditioners

[ksanders]

I need to aquire Marine Air Conditioners, but am a total newby to this area.

My boat will be in Mexico much of the year and I need keep it livable.

What are your recommendations?

What I have now are furnaces that will be removed, leaving the ducting in place for re-use.

What are my alternatives?
Are all of them sea water cooled?

Thanks!

 

[O C Diver]

Not sure I would remove your furnaces. My preference is the raw water cooled all in one units. I have one for both staterooms, one for the saloon, and one for the pilothouse. All 3 units are 12,000 BTU reverse cycle to do both heating and cooling. IMO, smaller units are better as they allow you to cool just what you want and make each area the ideal temperature.

The best efficiency comes from extremely short duct runs with the least amount of bends. Two of my units have less than 4' of duct work. Don't underestimate the amount of cooling required for areas with lots of windows such as your helm station. Too large a unit won't run often enough to dehumidify the area. A perfect sized unit will run 90% of the time on the hottest days.

Ted

 

[Larry M]

We did the same thing when we brought Hobo from Alaska to Mexico in 2007/2008. I waited too long to sell the Espar heater though. I paid extra shipping from southern California to the buyer in Seattle. There weren’t many people in California looking to add heat to their boats.

We installed 2-16k BTU Dometic Vector Turbos. We went that route after polling as many Krogen 42 owners as we could find who had AC on their boats. That was invaluable. They gave us an idea on the unit(s) placement, routing the duct work, makeup air grills, where to mount the pump and water lines. We went with 2 identical units so if we lost one, we could still cool part of the boat plus it made stocking spares easy.

We purchased the units and materials in San Diego and I did the install. I was able to source everything there. If you can find a connection so you can pay dealers/installers cost you’ll save several thousand dollars. I found that the mark up was huge.

One thing that took a while to get use to was we could run the Espar on our house battery bank at anchor. With the AC units we had to run the generator.

 

[ranger58sb]

Our previous boat started with Marine Airrrrr Vector Compact self-contained units and they worked reasonably well, decent life span.

They evolved the Vector Turbo units, Dometic acquired Marine Airrrr, and the same units (with some evolution) are now called Dometic Turbo DTG. Re replaced the two ACs on the previous boat with the newer Dometic model, more airfow, quieter, rust-proof drain pan, all good... except I dunno about longevity yet. Sold that boat.

New boat came with Cruisair Stowaway self-contained units. Dometic has since acquired Cruisair, and the Turbo DTG is a replacement option (and we've replaced one, already). The Turbo DTG can be fitted with pre-existing control, if useful. For example, our Cruisair wall panels are all SMXir (or something like that, and we didn't have to change that fr the new Turbo DTG unit.

Recently, I've been reading about CTM Marine units, which seem to compare favorably with the Dometic Turbo DTGs... for less money. And they can use the same controls we already have. Our DTG installer became a CTM dealer last year too, have installed a few units, haven't had any warranty claims, but not enough time has gone by for them to rave yet. They specifically said they get really good warranty service from Dometic; verdict still out with CTM.

"Boat show discounts" are not uncommon with Dometic, or at least with a couple local dealers we have around here... and I think some of that depends on whether Dometic is offering the discount or not in any given year. (Our installer can sometimes offer us the same discount anyway.)

As it happens, I'm juggling the plan to replace our other 4 ACs, so I'm watching CTM closely... 'cause they still seem to be about $1K less expensive even after juggling "boat show" discounts.

-Chris

 

[Larry M]

…They evolved the Vector Turbo units, Dometic acquired Marine Airrrr, and the same units (with some evolution) are now called Dometic Turbo DTG. Re replaced the two ACs on the previous boat with the newer Dometic model, more airfow, quieter, rust-proof drain pan, all good... except I dunno about longevity…

We installed the 2 Dometic Vector Turbos in 2008. We never had any issues when we sold the boat last year and I talked to the new owners the other day and he said they’re fine for what it’s worth.

 

[tiltrider1]

It’s really hard to give good advice on marine a/c right now. The market is changing. Some of the old bomb proof systems have started out sourcing to China. Meaning past performance is not an indication of future performance. Then there are the new systems like what Webasto is putting out. They are self contained, can’t be serviced are much cheaper and haven’t been around long enough for any one to comment on.

The best systems on the market currently are referred to as chillers. They are the bomb, but they require 240v and are very expensive.

We are testing the Webasto units. So far no issues but the installation is only 3 years old.

I would suggest you do some serious research and make your best guess on current quality vs cost.

 

[Graeme Walker]

We have same boat as you. Our 3 A/Cs are Marine Aiiiire and are original and I'm starting to get worried about longevity. 12kBTU under master bed (noisy, rarely use, too cold), 16kBTU under bench in PH used to cool Salon with vent above fridge (not enough cooling), 16kBTU unit under PH dashboard which has been ducted to Master. All units are relatively noisy. All of this is based on Ontario weather where it is hot (95F) and humid (90%), similar to Mexico/Florida but only July/August. The only issues we have run into is the raw water strainer getting plugged or pump not starting. Controllers aren't the best either but work.



I am seriously considering getting a 12v 5kBTU unit for the Master.
If any of the other units fail I will consider CTM or MarinAir (no 'e').

 

[Insequent]

I have seen some house mini-split systems installed on a few boats. Whether that could be an option depends on your boat's layout, but it can work very well and be cost effective.

The main compressor unit can be on your flybridge and have a box to cover it when not in use. That provides it with weather protection when not in use and some seating. If you need to run A/C then you likely wont need lots of seating up on the flybridge anyway. Then it comes down to whether or not you can fit one of more of the largish evaporator units on walls of salon and master stateroom etc. It could be an option worth considering versus dedicated $$$$ marine systems.

 

[rgano]

Great advice from the guys above. Did I miss any comments about powering with 240 volts ac versus 120 volts ac? There are smarter folks than I in the above group who can discuss the pros and cons, but 240 is of course more efficient.

 

[O C Diver]

Then there are the new systems like what Webasto is putting out. They are self contained, can’t be serviced are much cheaper and haven’t been around long enough for any one to comment on.

We are testing the Webasto units. So far no issues but the installation is only 3 years old.

My three 12K BTU units are Webastos. Installed 10/2015 during my refit. Will be 7 years this October without a problem, touch wood.

Ted

 

[heysteve]

As you might imagine, we run our 16 kbtu Marine Air Vector Compact (circa 2008) quite a bit down here in La Paz. The rust in the pan is not from the tray but from condensate water eating away at the base of the compressor. Why? Because the tray drains are not low enough to allow all water to escape with any kind of list. Definitely make sure whatever you're looking at has good, low tray drainage.

When considering a new install, make sure it's easy to clean the raw water system with BanacleBuster (or whatever) as you'll likely need to do that a couple times a year in high growth areas. Just cleaning the strainer is only half the problem.

 

[ksanders]

Thanks Guys!

Here is a question...

I have a through hull with sea cock that only serves my watermaker.

Is there a logical reason not to simply tee off of the output side of the sea strainer for the AC pump pickup?

I could fairly easially install a separate through hull but for the life of me I cannot think of why this is necessary.

What are your opinions?

 

[Larry M]

Your water maker will draw back water from the ac. The ac pumps are not self priming.

 

[ksanders]

Your water maker will draw back water from the ac. The ac pumps are not self priming.

The only way to solve that is a check valve or a dedicated through hull.
My boat is on the hard right now so it would be a perfect time to add a through hull.

 

[Larry M]

We ran our ac in July, August and September almost 24/7s. We had the March AC-5C-MD pump that was pushing close to a 1000 gph. Because of the flow rate, we were cleaning the strainer pretty regularly and we also had high barnacle growth. They loved the high water flow.

 

[smitty477]

Thanks Guys!

Here is a question...

I have a through hull with sea cock that only serves my watermaker.

Is there a logical reason not to simply tee off of the output side of the sea strainer for the AC pump pickup?

I could fairly easially install a separate through hull but for the life of me I cannot think of why this is necessary.

What are your opinions?

I believe that the flow rate required for your 45K BTU's will specify a size of seacock/hose/strainer etc to maintain minimum flow.
Does your existing system meet or exceed those limits?

 

[Osprey69]

Thanks Guys!

Here is a question...

I have a through hull with sea cock that only serves my watermaker.

Is there a logical reason not to simply tee off of the output side of the sea strainer for the AC pump pickup?

I could fairly easially install a separate through hull but for the life of me I cannot think of why this is necessary.

What are your opinions?

My water maker's manual specifies a stand alone seacock. My 2019 Dometic A/C manual does not specify.

 

[Osprey69]

We have same boat as you. Our 3 A/Cs are Marine Aiiiire and are original and I'm starting to get worried about longevity. 12kBTU under master bed (noisy, rarely use, too cold), 16kBTU under bench in PH used to cool Salon with vent above fridge (not enough cooling), 16kBTU unit under PH dashboard which has been ducted to Master. All units are relatively noisy. All of this is based on Ontario weather where it is hot (95F) and humid (90%), similar to Mexico/Florida but only July/August. The only issues we have run into is the raw water strainer getting plugged or pump not starting. Controllers aren't the best either but work.
I am seriously considering getting a 12v 5kBTU unit for the Master.
If any of the other units fail I will consider CTM or MarinAir (no 'e').

No matter the AC unit config, or capacity, if the ducting is inadequate so will be your comfort. I was able to solve my ducting problem, but I consider myself very lucky.

 

[Larry M]

My water maker's manual specifies a stand alone seacock. My 2019 Dometic A/C manual does not specify.

I wish companies could be consistent. It’s no wonder installations are difficult. This is from a Dometic installation manual dated 2011-2106. Note 3:

3) PUMP NEEDS DEDICATED THRU HULL NOT SHARED WITH OTHER PUMPS.

 

[tiltrider1]

Kevin, I plumbed my watermaker and my wash down pump to the same thru hull fitting. I have 3 a/c units. All 3 are fed from one pump which has its own dedicated thru hull.

 

[Comodave]

Thanks Guys!

Here is a question...

I have a through hull with sea cock that only serves my watermaker.

Is there a logical reason not to simply tee off of the output side of the sea strainer for the AC pump pickup?

I could fairly easially install a separate through hull but for the life of me I cannot think of why this is necessary.

What are your opinions?

Depends on how much you use the watermaker. If I were to use one thru hull for two purposes then I would have shutoff valves on each side to isolate the two items, watermaker and A/C. Then close off the shutoff valve for the item not being used. But that could end up being a PITA if you have to open and close the shutoff valves frequently.

 

[ksanders]

Depends on how much you use the watermaker. If I were to use one thru hull for two purposes then I would have shutoff valves on each side to isolate the two items, watermaker and A/C. Then close off the shutoff valve for the item not being used. But that could end up being a PITA if you have to open and close the shutoff valves frequently.

That would work. I use my water maker every day, and yes it might be a PITA but it would work.

 

[smitty477]

That would work. I use my water maker every day, and yes it might be a PITA but it would work.

If memory serves me well the factory thru hull for the 3 AC units on that model Bayliner is either 1" or 1-1/4".
What size ids the water maker?

More important - please check the required specs on any chosen AC units to be installed to see the minimum.

 

[Scottwb96]

Kevin-
Check out the Velair units! That's the next item(s) on my to-do list. Just finished the LFP conversion... So air will be next. I have the OLD Marine aiiiiiiire (lol, or whatever they are called) units...

The Velair ones are SUPER efficient (can run off batteries). Come standard with wifi control, not as an add-on. Really slick units!

Also, previously, the largest unit for 120v was about ~16K BTU. These ones will run a 21K BTU on 120v!

 

[Scottwb96]

oops, forgot the specs sheet...

 

[mvweebles]

Kevin - just finishing this for Weebles. A few lessons' learned (might be duplicate of other comments):

1. Ducting. Your existing ducting will not work. You need insulated ducting. The stuff is huge, and relatively expensive, but don't cheap-out here. At some point you'll end up in humidity.

2. Condensate drain. You will need a third hull penetration for the drain from the drip-tray. 1/2" thru-hull.

3. Single-pump for multiple ACs. They make a relay/junction box that can allow a single pump to service 2-3 AC units. You will of course need a much larger pump, but it's possible. Personally, I went with separate pumps.

4. The most common service item on the system is the AC raw water pump loses its prime for some reason. Make sure the sea strainer and pumps are accessible. You will not be sorry if you over-size your sea strainer(s).

5. The reverse cycle heat function works really well. I have no regrets about uninstalling my SigMarine diesel heater.

6. SureMarine in Seattle is great. They have all the ductwork parts in stock or can source them quickly. Tech support is good, and prices are fair. Despite being a loyal Defender customer for years, SureMarine is my first and last call for anything involving HVAC/Refrigeration.

Good luck -

Peter

 

[mickand]

Marine a/c for me is a pain in the a__, but I do understand why most use them.
I ripped out both my units, years ago and installed 2 x RV type units which are self contained and don't need any water supply in order to function. My salon unit lives on the flybridge partially under a bench seat and the staterooms unit lives on the front as per the attached photo. They are both by Dometic and have separate wall mounted programmers. I love them, but recently a friend of mine installed 3 x mini-splits on his 53ft trawler and if I were to do it now, that's what i would install on mine. The units are by Pioneer ($700 each)and he has one compressor unit in his cockpit and 2 tucked away up on the flybridge. The interior units just hang on the walls and are extremely quiet. You do need to run some small bore piping between the compressors and wall units, but the installation is pretty easy, providing you have the wall space to hang the units.
Any replacements needed are cheap and easy to replace - for example I can change one of my units complete in less than 1 hour at a cost of about $800 for a 16k btu unit.

 

[mickand]

Excuse the fenders out in the photo, but I was negotiating locks on the Erie Canal. I try not to commit this cardinal sin out in open water.

 

[ranger58sb]

2. Condensate drain. You will need a third hull penetration for the drain from the drip-tray. 1/2" thru-hull.

Or its not uncommon to plumb the condensate drain to an existing shower sump... depending on locations, height of source versus height of sump, etc...

-Chris

 

[ramkay]

I just installed on my GB 32 a 12K BTU water cooled unit. It's a Frigomar CL532. You have to have a thru hull seacock that you connect to a water filter with a basket and from there to the pump. The pump pushes the water through the condenser and then a thru hull nozzle throws the cooling water in the in the sea. The unit must be above the float line by about 10" as well as the thru hull nozzle. In my case, the unit runs on 220v (European standard) either on shore power or genset, for my Victron can only handle1200 watts. It draws 750 watts for starting and then 350 Watts eco mode. If you need to run it while cruising (not recommended) you'll have to ve the genset on. It's a reversible cycle unit that has both cool and hot air. Attached some pics. This will give you an idea. It comes in up to 16K BTU. More than this you would need two units. Hope this helps.