Compressor not producing cold air

[Peter3607]

My AC unit in the aft cabin (3 knob control) cycles when the fan is turned on. When I switch on the compressor, it too cycles however it does not produce cold air. The water pump is circulating and water is flowing out the outport. Either the refrigerant is low or the compressor is not functioning properly. If it's a matter of replacing the compressor, where can I find a new or used one? The unit is a Marine Air VR6K-H. Or is the last option to replace the entire unit with a new model more cost effective?
Any suggestions?

[tomschauer]

When you say the compressor cycles, how long does it run? It should continue to run until the thermostat is satisfied or it locks out on high or low pressure.

[Peter3607]

Let's just say that when I turn the knob once more after turning on the fan, I can hear the compressor kick on and the indicator light comes on. All remains the same but no cold air exits the vents. I've ket the system run for several minutes and nothing. At this point I give up and shut the AC unit off.

[Viper]

Take a look at the evaporator fins and ensure they're clean. If it's in a hard to get to enclosure, it may not have been cleaned in years. If it's in a storage space, make sure there is nothing blocking off the return air, it's best not to store anything in the same compartment that might block the evaporator or reduce air flow.

[Peter3607]

Thanks Viper. I will take another look at the evaporator fins. They are tucked in a tight corner but I will do what I can to clean what I can. As for the return air, that is already clean and should not pose a problem.
As this picture shows, the fins would be located in the top right corner of the picture.

[vineyardgray]

Oh they left you lots of room

Honestly I have no idea how an AC unit can function all jammed up like that

[tomschauer]

It looks like the one supply duct is wedged against the evaporator coil. I would think that would cause low air flow and a low pressure lockout. The older unit may have a manual low and high pressure reset switch. Are you 100% certain the compressor actually starts?

[waybomb]

If you can't get it working with some simple cleaning, and not putting money into it, I strongly suggest a new unit with a scroll compressor.
They are, for all intents and purposes, silent.
I happen to have webasto, but almost any brand with a scroll compressor will be so quiet, all you will hear is the air moving.
Well worth it.

[Viper]

Ya I'm not liking the placement of the duct. While it may not be the culprit, it doesn't help and will reduce overall efficiency.

[tomschauer]

I don't know of any marine manufacturer that uses a scroll compressor in anything under about 36,000 btu or more and 240 volt applications. Most are and have been rotary vane compressors for many years. These are the same compressors used in the super quiet LG, Mitsubishi etc, ductless splits. Most marine a/c manufacturers have been using Toshiba rotary compressors for the last 10 years or so. These are tough little units. If mounted properly and with a bit of insulation, like manufacturers have been doing for the last couple years, the fan makes more noise than the compressor. Especially, if they have a soft start incorporated into the control board.