Cruisair 16K BTU compressor overheating

[derfy]

I have two Cruisair A/C units, a 12K and 16K BTU, and until now have had few problems. They share a common water pump">raw water pump, and raw water discharge flow is good. They work well.

These units both cool and heat.

I was running only one of unit, the 16K, in reverse mode (heat), which had been working fine from some days. Then one morning, I turned on the unit at 4 am, went back to sleep, and 2 hours later woke up to a very cool cabin. No heated air. I checked the compressor (the cylindrical/spherical gadget in the condensing unit chassis) and it was quite hot, too hot to touch. I shut off the unit.

I remembered there is a reverse valve or solenoid that is actuated in heat mode, that sometimes gets stuck, and can be jarred loose with a tap of a screwdriver handle in the right place.

I tapped a few places that seemed likely candidates for such a valve or solenoid on the condenser chassis, but to no avail. Not sure where this valve is or what exactly it looks like.

Since this incident, the 16K unit fails to heat or cool, even though it "runs". Something was damaged when I ran it two hours and got the compressor hot. The 12K unit continues to work fine at both cooling and heating.

Has anyone treaded here before? I am climbing the marine A/C learning curve from the very lowest first step. Thanks in advance.