Scored a Marine Air Systems AC/Heat unit!

Feb 14, 2014
7,400
Hunter 430 Waveland, MS
My biggest concern is the sticker says it uses R22 refrigerant, which is being phased out.
Yes and about 80% of all commercial, older homes, auto AC are using R22.
We are on a collision course.:rolleyes:
I will not engage on the refrigerant phase out, but alert you to this fact.
____
I just fixed my same 16k BTU unit about 4 months ago. The Tecumseh® rotary compressor was checked by my AC repair service with a High Tech computer gauge, but I had to show him where to connect is Temperature probes on the Sea Water cooler.
My 16K compressor was ID'd by Tecumseh® as built in 1997. If you get the number off the side of your compressor, I can decode it for you.;)
_____
Bottom line was my Tecumseh® compressor was in great shape. No R22 was needed.:clap:
If you look on the top of the Compressor, there are 2 black connections [pict 2]
The smaller is a combination Surface Temperature and Current overload. Mine was bad and I got a wholesale replacement part, per Tecumseh®, and replacement for total installed cost of $150.:)

The rest of your unit is basically simple. I would use a water side heat exchanger, cleaner like Barnacle Busters to circulate and clean it prior to installation.;)
I keep mine clean, by periodic [ ≈4 times a year] addition of 1" Chlorine tablets in the intake water strainer.

You got a great find since a new 16K unit is about $2500 brand new uninstalled.

A happy MarineAirrr. owner.

Jim...

PS: I have all the manuals and even the Tecumseh® detail shop drawings for the compressor. I will share them in a PM. Beer is always welcome bribe.:beer:

PSS: Tecumseh® service representative was fantastic with his help.
 
Last edited:
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Hopefully it will work with a replacement refrigerant if needed.
Per Tecumseh®, they have not tested that compressor with the new refrigerant, but told me it was estimated to drop 35% on the output and the water exchanger may not be sized correctly.

Since there is a lot to be installed, like the remote controller, power, ducting, seawater pump and sea water pump relay panel, your adventure is just starting. I can help, but not on this forum link.
Jim...

PS: R417a is NOT a direct R22 replacement. Sorry.

PSS: https://www.chemours.com/Refrigerants/en_GB/products/freon59.html
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Dometic bought Marineair and they should be able to support the A/C. My old R-22 Cruisaire compressor rusted out a couple of years ago and lost it’s R-22 charge. Between the compressor, labor, and R-22 cost it was totaled. There isn’t a good replacement for R-22 refrigerant in a unit designed to run on it. In addition you have to be a certified, licensed A/C tech to work with the gas, so it isn’t a DIY job.
 

Ward H

.
Nov 7, 2011
3,645
Catalina 30 Mk II Barnegat, NJ
@DayDreamer41
Thanks for that link. I found the thermostat manual and a AC unit manual that is close enough to my unit to give me what I need for install.
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
AC unit manual
Figure 11 and 12 in the Vector manual is close. The Assist Start PTCR is old style compressor start up.
I replaced that compressor startup with a Hard Start combo, 2 years ago.
You may not need the Pump Relay Panel . if you only have ONE unit running on your sea water pump. I have 2 AC units and need it. I have a magnetic coupling sea water pump with a Gronco Stainer.

If you look on those Figures, you will see a small circle with "OPT" in it on the Compressor pictogram. That is the Part, I referenced in my post#21.
Good Luck...
Jim...
 

capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
After our winter experience I’m sure the Heat side is as important as the cold. Great score Ward!!
Sady these units will only heat in water temps above 40 degrees, so you may have been outta luck this winter!
 
Feb 14, 2014
7,400
Hunter 430 Waveland, MS
Sady these units will only heat in water temps above 40 degrees
They will still extract heat from the water, but not as much, if it was warmer water.
If you have a fouled seawater exchanger, even less heat.

Although the circulating air may be, say 50°F it will keep your boat interior warmer than freezing.
Also the 16K Btu/hr is the rating, in colder water the Heat will be much much less.
Jim...
 

Ward H

.
Nov 7, 2011
3,645
Catalina 30 Mk II Barnegat, NJ
Figure 11 and 12 in the Vector manual is close.
The Vector manual appears to be close enough to help get me through the install layout, plumbing and wiring. I'll PM you with additional questions as I get closer to the actual install.
Thanks
 

capta

.
Jun 4, 2009
4,766
Pearson 530 Admiralty Bay, Bequia SVG
They will still extract heat from the water, but not as much, if it was warmer water.
If you have a fouled seawater exchanger, even less heat.

Although the circulating air may be, say 50°F it will keep your boat interior warmer than freezing.
Also the 16K Btu/hr is the rating, in colder water the Heat will be much much less.
Jim...
Having spent a winter aboard in RI, I can assure you that reverse air units do NOT make any heat when the water temp gets low enough. Thankfully, someone on the dock mentioned this to me before I began tearing the unit apart trying to find the problem.
 
Mar 20, 2011
623
Hunter 31_83-87 New Orleans
I have a 16k unit on my 31’. When planning your install, look at the number of ducts you will need. PO installed 2 small ducts and I had a problem with the compressor freezing up during the night. Added addl and larger duct work for air movement and haven’t had a problem since.