AC/HEAT system

[KEVMAR]

I am looking at replacing my current unit which was installed in the 90's .. the compressor is shot and cant be fixed.. I have been looing at the dometic/marineair units and have seen one which is self contained 16000,btu and has air and a heat pump ..and others that done mentioned the heat pump part in the description.. what is the difference and should I stay away fro the heat pump There is about $500 dollar difference in the heat pump vs non heat pump the heat pump being 500 less. thanks for your input I have a 1983 36 albin trawler .

 

[Comodave]

I have installed Mermaid 16K with reverse cycle units in 4 different boats. Really like the Mermaid units. No interest other than a satiffied customer.

 

[DavidM]

Air conditioning units that can also function as a heat pump, so called reverse cycle, have a solenoid operated three way valve that reverses the normal flow and lets it pump heat from the raw water to the room, rather than pump heat from the room to the raw water as it does in cooling mode.

That little valve probably costs Dometic or whoever 50 cents. It does take a bit more electronics to manage it properly. That is why it costs more and like everything sells for many times more.

Heat pumps that are raw water cooled like most marine systems work well until the water temps get down to 35-40 degrees. Then the raw water starts freezing in the heat exchanger and finally plugs up, stopping the system. Most newer units have sensors that shut the heat pump down below 40 degrees raw water.

David

 

[sbu22]

I don't know about reverse cycle performance, but will echo Comodave on Mermaid. Great units, great factory support on the rare occasion you need it.

 

[KEVMAR]

Which mermaid unit ??

 

[sbu22]

I've bought 3 units from them. Here in the semi-tropics, never considered the add-on heat (reverse cycle). This is going back to the 90s to maybe 2010 - three blow boats. As I recall, maybe 4k to 6.5k AC units.

 

[tiltrider1]

I bought a boat that had reverse cycle heat pumps installed. The PO used the boat south of the border and only ran AC. I use the boat in the PNW and primarly use them for Heat. You just never know were you and your boat is going to end up or what the next buyer is looking for.

 

[Comodave]

I installed the 16K btu with reverse cycle units.