A/C orientation in boat question ...

[Jennimar]

We purchased our 1990 310 Sundancer around Labor Day last year, and it is Great (mostly). The A/C unit coninually has been freezing up after running for 10 to 12 hours. While running it blows cold and we have no issues, until the find for the coils freeze up.

Had a few opinions from friends, but wanted a better source. The intake vent/filter comes from the main cabin under the front V-berth. The A/C unit is located under the V-berth, and the coils are on the side of the unit closest to the bow.

My thought is that the unit was installed backwards and that the coils should be facing the vent opening (towards the main cabin). It seems to me that the return air needs to come from the main cabin, through the vent/filter, around the entire unit, and then reach the fins/coils.

I have checked the water filter basket and the air filter in the cabin ... all clean there.

Any thoughts on what the proper orientation of the A/C unit should be ?

 

[NotHerDecision]

I agree with you but...

you most likely have one of 2 issues.

1. the refrigerant is low. You should have this checked.
2. The fan is not working properly. (Recently I had a unit that wasn’t running on low speed)

so. I would set the fan on the unit to run on high all the time and see if that corrects it. Then have the refrigerant checked before you turn the entire unit around and have to modify the water, drain, and air ducts.

 

[Creekwood]

I would think it should not matter how it is oriented since the air is drawn into the unit over the coils and then blows out through the ducting. Here is what Dometic suggests:

 

[PatSea]

I have had icing of the coils a few times over the years. Each time it was on a very humid day and I had let the cabin door open enough that the load of humid air caused it to ice over. I set a fan on the coils for an hour or so, melted the ice and all was good.

 

[b_arrington]

The orientation doesn't really matter much relative to airflow. The more determining factors are how to route the air lines and water hoses. The air is going to get into the system so long as there is an unrestricted supply.

As an example I have 2 AC units on my helm deck, port and starboard, each mounted inside the bulkheads. There's an intake grille with a filter - then no ducting at all. The system will pull in air through the grill and it gets sucked into the fan. Both AC units are mounted the same direction. That means one has the air intake facing in, the other is facing out. They both work fine.

 

[Korkie]

Had same issue with freezing up. A/C unit in same place on our 340 with coils facing aft. When we had freeze up issues, it always came back to fresh air restriction. Usually from putting the Yeti we have on the floor in front of the birth being too close. We keep it at least 8 inches out from the air inlet and so far so good. We do keep a hair dryer handy if it does re occur.

 

[BlueYonder]

Some marine A/C units have an automatic de ice mode that can be enabled. Check your thermostat manual to see if it has one. Where is your thermostat located? Sometimes a remote temperature sensor need to be installed at the return air grill because the thermostat is in too warm of a location (direct sunlight, too close to the hull, etc.)

 

[Jennimar]

Thank you all for your responses. Going to check a few of your suggestions and see what can be done

 

[Express 390]

Thank you all for your responses. Going to check a few of your suggestions and see what can be done

Another reason for icing up is an improper charge if the pressure is too low it will cause an icing condition

 

[Jennimar]

I went through everything and it all seemed correct. Took the advice that the cooling vents might have debris in them. Brushed out the cooling vents and vacuumed out that debris. Appeared to be quite a lot. After this cleaning, we have had no issues.

Thank you everyone.