Reverse Cycle Heater Question 1

[Andy1237]

Turned my heater on without thru-hull open.OOPs. Opened valve and turned on and it would not pump. Tried the old wet vac on the exit hole and could not get any water. Checked pump-plenty of pressure. Checked in hose all clear but NOTHING would come out. When I ran the unit it just froze over. Turned off and threw on every blanket. Net morning, I clicked it on just to see what would happen-worked fine! What was going on?
Can low batteries in a thermostat do that?

 

[Andy1237]

Reverse Heat Cycle Question 2

So the unit worked fine Saturday am, worked fine all through Saturday night to Sunday morning. But later Sunday morning it would not get warm! Water pumping all the way through, fan blowing, but no heat.

 

[Rich Stidger]

Question 1:

It sounds like the unit iced-up and froze solid. The typical solution is to put it into cooling mode and then it will heat the seawater in the heat exchanger tube and thaw it out. As soon as it gets running again you can switch back to heat mode.

Question 2:

This sounds like the compressor is not running or the thermostat is satisfied. Can you get it to switch from heat to cooling by changing the thermostat setting? Is there a breaker that got tripped that supplies power to the compressor?

I am only familiar with the Marine Air brand of A/Cs, so it you have something else I may not be able to help.

 

[petersea]

If it is a marine air unit with electronic controls you can set it up to auto "defrost" in the program read the manual for further info and instructions. The default mode is "no de ice". Unit has setting for 1,2 or 3 mintues if no temp change in one hour. Manual is online if you need it.

 

[Andy1237]

Its a Mermaid Air unit. I don't think it has a defrost mode. Rich, it probably was frozen solid and I was not patient enough and didn't think about using the AC to thaw (counter intuitive thinking!). There is a breaker on the unit for the compressor. I have had to reset it using AC but didn't think about that with heat.

 

[Andy1237]

Duh! The compressor breaker! Popped in the Reset button and it heated right up. I've had to "reset" for AC a few times but didn't think about it for heat. Quite warm when the compressor is working and the water is flowing!