Post edited 9:21 pm – June 30, 2010 by tmh

Just getting my unit back online after a few years where the boat wasn't used – new to me so figuring things out. 12,000 BTU, water temp around 70 F and air temp only 75 or so. 1988 boat, not sure if original equip. A/C or not. Marine air, Vector type (I think) three knob control.I finally got controls figured out/repaired and good cooling water flow from pump to discharge. Compressor turns on, but coils get hot even when control is turned to full "cooler". This is a three dial control, bottom control is for warmer-cooler control.

The unit could well need recharging, but would it heat (even when set to cold) if that were the case? Other ideas? Could it be the temp probe? Control box on back side of controller behind temp control dial? Ideas? Thx.

Also, while I'm asking… is there a filter on these things that needs cleaning? There is a simple filter in the wall cover piece where air would get into the area, but any directly on the unit? If so, where? How do I get it out to clean?

Also read this post for the answer to your filter question & more….

http://marine-ac.com/forum/mai…..e-checkup/

Steve~

Correct…If you remove the wire it can not send power to the reversing valve to energize it.

If you do it on the back of the control and your sure it's Marine Air…It will have two yellows connected on the t-stat and then tied together with a butt splice with one yellow heading out to the unit…The connectors on the back of the control are push on spades…Remove both.

Yes there is a calibration screw hole on the back of the t-stat, but I don't want you to mess with that yet…It could be fine & you will only get it out of calibration if the problem lies elsewhere…We have a few more tests to do before fooling with that…Removing the yellow is one that tells me what to ask next.

Steve~

OK, just back from the boat. I detached the yellow wires from the temp control knob back. The compressor then did not turn on no matter where I set the temp. Fan ran, but when set to "run" no compressor, nor the light on the control box lighting up to tell me the compressor was running. Reconnect the yellow wires, compressor fires up and it seems to get hot air. The cooling water (from the pump) section of the compressor was starting to ice a bit near where it comes in from the pump. It seemed less cold near where it exits the unit to overboard discharge, but still cold.

So, does this tell us anything? I had read about knocking the reversing valve to free it, but truth is, I have no idea what it looks like or where it is on the unit.

Thx.

Before you spend any money though…I'm still concerned about if the reversing valve is stuck…One more thing you can try…

Reconnect your yellow wires…Then go to the unit & find the reversing valve…It will have a Tube about the diameter of a quarter with 3 smaller tubes soldered into the top & one out the bottom….You will find a electromagnetic coil with two wires going into it attached…Either remove that coil…It's held on with a single nut, and once the nut is removed it will slide off a shaft…Once off, stick a screwdriver in the coil hole to absorb the heat it generates to keep it from melting….Then start the unit…If the unit cools then the valve is not stuck…If while running you can feel the magnetism on the screwdriver…Then there is a problem with the control….Replace the control & re-install the coil.

Steve~