www.iFourWinns.com

I was hoping for some insight. Two weeks ago my heat was working well on boat. when I left I left the heat on at about 75. When I returned this past weekend, the boat was chilly, and upon inspection, I had a ice build up on the unit. Has this happened to anyone, and what is the cause?

Cheers

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Vista 318 2007

You need to do a search. The answer is a very common one. Clean your filter and screens.

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One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy

It happened to me last winter. I had my unit set to 55 degrees. The outside temp was in the teens and 20's for several days. I can say that my filters and screens were plenty clean though. The water temp was right above freezing in the slip. The only thing I could guess was that the water temp and outside temp were just too low for it to keep up. This winter, if we experience those temps again, I will take off the seat cushion and access pane just to be sure that I have increased the opportunity for warmer air to surround the unit to hopefully prevent this.

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Current Boat:
2004 Sea Ray 320 Sundancer "Nauti Luvin'"

Previous Boats:
1999 298 Vista "Seas The Day"
2008 H200SS "Nauti Luv"
2006 Tahoe Q4

I don't have heat or AC, but is this unit a heat pump?

The 318 unit is Reverse-Cycle. With a reverse cycle heating system, a reversing valve reverses the flow of refrigerant, making the condenser an evaporator and the evaporator a condenser.Reverse cycle heat will not work with a raw water temperature below about 45-50°F and the compressor is stressed near these temperatures. Thus the freeze up can occur. Opening the unit up to warmer air in the cabin, will not prevent the freeze up if the water temp is too low for the compressor to keep up.

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One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista

Current Boat: 2004 Chaparral 235 ssi cuddy

Thats what I was driving at. Basically, it is a heat pump (reveres-cycling), and heat pumps do not work will in temps (I think) below 50. Thats way you see them in the southern states. So for it to shut down and stop is not surprising. Just curious!!

Cap'n you ever need a job give me a call, we have guys in the feild who can't understand that, oh ya they can't fix anything either!!

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2001 328 Vista "Nauta Dream 2"
AB Inflatable 10AL "Little Dreamer"
2000 248 Vista
1997 225 Sundowner


Mike

What's the water temp? That, more than the air temp, drives how the system performs for both heating and cooling.

I believe the manual has a graph showing what performance a unit is capable of using across various water temps. As I recall it's not designed to work with water cooler than 45F.

If you think about how they work it's based on being able to extract heat. Either by using the raw water to warm up the refrigerant when it's uncompressed, or to cool it off after it's been compressed. The system works both ways. One direction releases heat from compressed refrigerant (heat), the other uses the tubes to collect it (AC). The raw water is where the heat is transferred. Either from the water (heat) or to the water (AC). But this cycle only works if the water is above a certain temp for heat, or below a certain temp for AC. Thus in the summer if the water temp is very warm the AC will only be able to cool the cabin down by only so much.

I forget exactly what causes the systems to ice up. It can happen using either mode; heat or cooling. It has a lot to do with the outside humidity too.

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-Bill Kearney, 2005 348 Vista

Icing is caused by conditions which are directly related to your saturates suction temperature (refrigerant temp on the low side of the system) So if the water is too cold (in the heating mode) the unit will run for a long time and not satisfy your thermostat which in turn will lower you saturated suction temp and cause icing on your coils, onece you have a little bit of icing you then create lack of air flow......and so on.

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2001 328 Vista "Nauta Dream 2"
AB Inflatable 10AL "Little Dreamer"
2000 248 Vista
1997 225 Sundowner


Mike