We replaced the original Dometic AC/heat unit with the same about 5 or 6 years ago. Went with a new 16,000 BTU which was much more compact and efficient and we even installed a Smart Start capacitor so that our unit will run off our Honda 2000 generator. However, we have had nothing but trouble from this unit and have replaced the circuit board 3 or 4 times, the first 2 times under warranty but twice on our dollar (a lot of dollars). The digital thermostat is a POS and very hard to operate. The thing is that we almost never use this unit. In the winter months we have been in south FL so not needed and in the summer the boat is in a slip and we only visit to check on things and run a plug-in dehumidifier 24/7. We had a relay replaced in the spring and just tried the unit yesterday for the first time and not working again. We do not know the reason yet but a service visit is scheduled for Monday and I am expecting the worst...maybe another circuit panel replacement. My question (finally) is what brand of units should we consider to replace this Dometic POS? With all the repair costs we could have purchased a new unit by now. Wondering what others have experience with in terms of reliability? Could part of our problem be lack of use? Thanks!
Marine AC Unit
- Thread starter Cat 310 #1 in GA
- Start date
I installed a Marineair Cabinmate 12000 BTU unit back in 1993. It runs pretty much 24/7 here since it runs its dehumidification cycle when I am not on board.. I have had outstanding service from the unit over the 32 years of running. The only failures were not faults of the unit.. Failures were control board after a lightning strike.. a compressor failure because the installer 
banghead:me) allowed condensate to build enough to touch the bottom of the compressor can and rust a pinhole through.. The machinery inside was fine but the corrosion was such that a few more pinholes were there .. that was after 16 years. I replaced the compressor and returned it to service.. I had one March pump fail after 17 years.. I replaced it with the same brand and model.. .... Now.. that unit was built before Dometic bought them.. I have no experience with the newer ones.. Thing is, Dometic doesn't build the components, they only give a specification to a builder who actually puts it together.. They use components that are purchased on a low bid for quantity and these components may be different from year to year.. its kinda a crapshoot ..
When I buy another, it will have a composite plastic drain pan and quality coils and heat exchanger.
banghead:me) allowed condensate to build enough to touch the bottom of the compressor can and rust a pinhole through.. The machinery inside was fine but the corrosion was such that a few more pinholes were there .. that was after 16 years. I replaced the compressor and returned it to service.. I had one March pump fail after 17 years.. I replaced it with the same brand and model.. .... Now.. that unit was built before Dometic bought them.. I have no experience with the newer ones.. Thing is, Dometic doesn't build the components, they only give a specification to a builder who actually puts it together.. They use components that are purchased on a low bid for quantity and these components may be different from year to year.. its kinda a crapshoot ..When I buy another, it will have a composite plastic drain pan and quality coils and heat exchanger.
I have a Dometic 16000 BTU emerald series split system. Definitely not my choice; PO had it installed one year before I purchased the boat. It works very well and ventilates the entire boat. Over 10 years, I replaced the compressor relay & more recently, the circuit board. Fortunately, I was able to do the repairs myself, so it was not terribly expensive. My fear is that it will become expensive when I have to replace air handlers, etc. Much easier to drop in a self contained unit, but I don’t have the ducts for that.
I have seen air conditioners by Flagship of south Florida. They claim that their system has readily available generic parts that can be obtained at a hardware store.....no printed circuit boards. They will build a custom self-contained unit for your space. Last time I researched them, their unit was not reverse cycle; they used heating elements for the heater. I have no personal experience with Flagship; however, I had a friend who had one & was satisfied.
Don’t know about lack of use being the problem. Only thing that I am aware of is that Dometic recommends occasionally running heater in summer & AC in winter to prevent reversing valve from getting stuck (on a reverse cycle unit).
I'm guessing that the rarely used system has growth in the seawater cooling system, and is not getting sufficient water flow.
Good/honest marine AC contractors, especially in SoFla, are one of the most difficult contractors to find.
Once I found one, I would fly him down from the states to the Caribbean to work on my AC and refer systems when needed. When you run a $26k a week (back in the early '80s) charter boat, you can't just say, "Oops, I'm sorry, but you won't have any AC in your cabin this week." nor can you put the charter off until the repair is made. If you find one, cherish and nurture the relationship. However, it sounds like your guy isn't very good at his job. It isn't enough to get the system up and running. One must find out WHY you have the same problem over and over again!
When I first went to sea, I was an electrician on a 630' ship. One day I was sitting across from the AC guy and I asked him how AC worked. He basically replied that to make things cold you use heat. I added that to the theory that space was infinite and the light from the stars I was seeing was from millions of years ago. yeah, OK!
One year,in Granada after our annual haul out in Trinidad we found our refer system wouldn't work (refer & AC service personnel are usually the same company), so we had the system charged there, before sailing back to Grenada. The next morning it needed more gas. 3 more AC guys came and went with various ideas, from the unit was too old to the best (by popular opinion on the local forum) guy in Grenada saying we should tap a solenoid with a rubber mallet every time we started the unit. That suggestion was idiotic and I got mad. I went online and in half an hour I knew all there was to know about my unit and I asked Nikki to find the leak. Five (5) minutes later she was back with oil on her fingers and the knowledge that the RFD had a leak. FOUR PROFESSIONAL AC guys with sniffers and gauges had cost us us$500+ were unable to solve such a simple problem. I ordered an RFD and the fittings we needed, called back the one guy who we liked (no it wasn't the nut job that the cruisers loved), had him drain the system, install the new RFD and vacuum the system and refill it. That was the last time we had anyone onboard for refer or AC work, except to use their vacuum (while they sat around drinking beer), because we didn't want to buy and stow one, for the few times we needed one. We carried the gas, gauges and soldering tools to do everything else.
However the secret, and it isn't much of a secret, to keeping equipment functioning well is to use it as much as possible. As the fellow above said, his AC worked day and night for something like 32 years. Many snow birds find a it a lot of work to commission their boats after 6 months away. Probably more than I did in daily use over the whole year.
Good/honest marine AC contractors, especially in SoFla, are one of the most difficult contractors to find.
Once I found one, I would fly him down from the states to the Caribbean to work on my AC and refer systems when needed. When you run a $26k a week (back in the early '80s) charter boat, you can't just say, "Oops, I'm sorry, but you won't have any AC in your cabin this week." nor can you put the charter off until the repair is made. If you find one, cherish and nurture the relationship. However, it sounds like your guy isn't very good at his job. It isn't enough to get the system up and running. One must find out WHY you have the same problem over and over again!
When I first went to sea, I was an electrician on a 630' ship. One day I was sitting across from the AC guy and I asked him how AC worked. He basically replied that to make things cold you use heat. I added that to the theory that space was infinite and the light from the stars I was seeing was from millions of years ago. yeah, OK!
One year,in Granada after our annual haul out in Trinidad we found our refer system wouldn't work (refer & AC service personnel are usually the same company), so we had the system charged there, before sailing back to Grenada. The next morning it needed more gas. 3 more AC guys came and went with various ideas, from the unit was too old to the best (by popular opinion on the local forum) guy in Grenada saying we should tap a solenoid with a rubber mallet every time we started the unit. That suggestion was idiotic and I got mad. I went online and in half an hour I knew all there was to know about my unit and I asked Nikki to find the leak. Five (5) minutes later she was back with oil on her fingers and the knowledge that the RFD had a leak. FOUR PROFESSIONAL AC guys with sniffers and gauges had cost us us$500+ were unable to solve such a simple problem. I ordered an RFD and the fittings we needed, called back the one guy who we liked (no it wasn't the nut job that the cruisers loved), had him drain the system, install the new RFD and vacuum the system and refill it. That was the last time we had anyone onboard for refer or AC work, except to use their vacuum (while they sat around drinking beer), because we didn't want to buy and stow one, for the few times we needed one. We carried the gas, gauges and soldering tools to do everything else.
However the secret, and it isn't much of a secret, to keeping equipment functioning well is to use it as much as possible. As the fellow above said, his AC worked day and night for something like 32 years. Many snow birds find a it a lot of work to commission their boats after 6 months away. Probably more than I did in daily use over the whole year.
Anyone have experience with the Mermaid AC/heat systems? I have spoken with them and their service is excellent. Have a friend who went out of his way to purchase and install one due to his opinion that they are much better quality than Dometic. They have a 5 year warranty compared with 3 years from Dometic and 2 years from Webasto. I just can't find any recent comments online from people who have these units. I just hate to buy another Dometic unit given how terrible my previous unit was and now needs replacement after 6 years.