Air conditioning battle continues ...Cabin will not cool.

[bigdealsam]

2012 R25 with Dometic 16000 BTU Air unit. Simply will not get the cabin cool. Thermostat registers in the 80's either on shorepower or the generator. I see a steady (but certainly not overwhelming) stream of water dispelled and the strainer appears to be clean. I feel cool air from the vent beside the Captain's chair and the vent beside the passenger seat but not "real" cold air. Those are the only two vents that appear to be blowing cold air. Nothing in the V berth.

The air is cool enough to drop the cabin temp down a few degrees but not enough to be anywhere near comfortable.

Is it possibly a lack of freon? Am I missing any of the vents that might be blocked or turned off? Something else?

Any help is much appreciated.

 

[Matty]

I would think either low refrigerant or your water line is partially blocked. Not sure about in your area but in Florida we can get some blockage from seawater growth which could explain what you describe as less than powerful flow. Sounds like equipment is functioning.
Heat is taken out through the water so might be the issue. There are YouTube videos on how to flush or a service could do it.

 

[CaspersCruiser]

The volume of conditioned air delivered to the cabin is marginal at best. If there is significant sun coming in the cabin windows, the system simply cannot overcome the solar heating. The only way to mitigate this is to draw the curtains on the windows facing the sun and the only way to ventilate the cuddy is with a fan.

To make the most of the conditioned air on my 2012 R27, I made reflective heat screens that attach with Velcro to the window frames. They’re very effective. Even on the hottest days (90°+), I can cool my cabin into the low 70s. I put them in windows facing the sun and on the overhead hatches. Here’s a link to a post I made about them:

viewtopic.php?f=24&t=12705

I only use the heat screens at the dock or anchored. The only way to mitigate solar heating underway is to tint the windows as Tim McMillan, aka “Boatdreamer” has done. He also installed an additional port side vent.

 

[fishheadbarandgrill]

Probably a control board. I had similar symptoms on a previous boat.

 

[knotflying]

Has this always been a problem or is it something new? Are you an original owner or bought used? Just wanted to know the history of your problem. There can be a few factors that result in your issue, some mentioned above. Most importantly is the shading of the windows. When in a hot climate at the dock we pull the curtains and shade the hatches. I did change my water pump to a larger flowing one and that also helped. There is also a setting on the thermostat that allows for deicing the coil. This will remove any ice build up on the coil which leads to reduced air flow around the coil. Additionally, when I had my compressor replaced I had them use R-22 and that made a difference as well. As an initial check I would see what the temperature is of the air discharging from your vents. It should be about 14 to 20 degrees lower than the ambient air. If it is running hotter than that it indicates that you may be low on refrigerant or you are not getting enough water flow to aid in cooling.

 

[scross]

Just a reminder for those with older a/c units on their boats or at home using R22 refrigerant that new EPA rules will completely ban all production of the R22 (aka Freon) refrigerant next year. Supplies of R22 will slowly sell out until you can’t get it anymore or at best it will be recycled R22 and be very expensive.
Don’t know if the new a/c units on our boats use R22 or the newer R410a refrigerant. I have been told by several HVAC tech that you can’t use the new R410a refrigerant in a unit designed to work with R22.
https://www.serviceexperts.com/blog/wha ... affect-you

 

[Matty]

Newer ones are 410a which is required.
Since R22 and R410a are completely incompatible you either will need a retrofit or new unit. But as old as it will be that will not be all bad. It is my understanding retrofit cost is equal to or more than new unit.

 

[bigdealsam]

Has this always been a problem or is it something new? Are you an original owner or bought used? Just wanted to know the history of your problem. There can be a few factors that result in your issue, some mentioned above. Most importantly is the shading of the windows. When in a hot climate at the dock we pull the curtains and shade the hatches. I did change my water pump to a larger flowing one and that also helped. There is also a setting on the thermostat that allows for deicing the coil. This will remove any ice build up on the coil which leads to reduced air flow around the coil. Additionally, when I had my compressor replaced I had them use R-22 and that made a difference as well. As an initial check I would see what the temperature is of the air discharging from your vents. It should be about 14 to 20 degrees lower than the ambient air. If it is running hotter than that it indicates that you may be low on refrigerant or you are not getting enough water flow to aid in cooling.

I purchased the boat last November so this is the first real summer season that we have experienced. I am near Charlotte NC on Lake Norman and the ambient temp has been low to mid 90's recently. I can't get the air below 83 or so. The survey that was done prior to purchase did not note any air conditioning concerns.
I will take your advice and measure the temp at the vents. I suspect the refrigerant will be low. Thanks much for the ideas. MUCH appreciated.