Understanding Marine Air Conditioning Systems

Understanding Marine HVAC systems

Living on a boat full time in the southern area of the United States is great; we enjoy stunning waterways and favorable temperatures that permit cruising year round.

But cruising in the hot days of summer would be difficult if it were not for the marine HVAC we have on board. You might have a unit aboard your vessel.

But how do marine air conditioners function?

Marine HVAC systems make use of coolants that effortlessly convert from a gas to a fluid and back again. The coolant used for years was R-22 or Freon. A few years back Freon was replaced with Puron or R410A, a more environmentally safe gas. This compound is used to move warmth from the air within a vessel to the raw water used for reducing the temperature.

A marine HVAC system is comprised of two key elements. They are a compressor/condenser and an evaporator/air handler. The refrigerant starts at the condenser/compressor as a cool, low-pressure gas. The compressor compresses the liquid. The solution leaves the condenser/compressor as a blistering, high pressure liquid and moves into the air handler/evaporator. The liquid goes into the air handler/evaporator; on the other side, the fluid's weight drops. When it does, it starts to diffuse into a gas.

As the liquid converts to a gaseous substance, it removes heat from the air being stimulated by the air handler. When the gas returns to the condenser/compressor, the heat in the air is at that time transferred to the raw cooling water that is circulating in the condenser/compressor. The coolant then starts its trip throughout yet again.

The salt cooling water used on marine reverse cycle systems is pulled from the waters the boat floats in. The sea-cock fitting is utilized together with a number of clamps and hoses to affix to a moving pump that pulls water through a sea strainer. The water is pumped through the strainer and after that the compressor/condenser and in the end, overboard.

Coupled to the evaporator is an air handler (fan) that moves the air within the boat. Hot air weighs less than freezing air, so the hot air within the vessel goes up to the uppermost part of a cabin. The hot stateroom air is sucked into the reverse cycle system by way of intake vents and cold air is moved back into the boat. A thermostat turns the condenser/compressor off and on to uphold the preferred temperatures.

To attain the reverse cycle utility on the system, the system contains a valve that lets it change between "heat" and "air conditioning." When the valve is turned one direction, the condenser/compressor runs like an air conditioner, and when it is switched the opposite way it changes the flow of the liquid in the device and runs like a heater. When the unit is in the heating mode, heat is pulled out of the salt cooling water and the heated air is transferred back into the cabin; simply a turnaround of the process.

Marine HVAC units can be exceptionally efficient in their utilization of energy. But one issue with them is that the coils in the evaporator amass ice. The HVAC system has to thaw this ice frequently, so it switches itself back to heat setting to heat up the coils. Once the frost is thawed, the unit changes back to air conditioning mode.

One more concern in the warming mode is that the more frigid the water the vessel lies in, the less heat the system will have the ability to provide.

Troubleshooting
The primary source of marine air conditioning problems is the flow of the water, possibly ninety-eight percent of the time. This is what you have to know to resolve most marine HVAC concerns.

1. Make a point of knowing the proper flow of water from your air conditioning outfalls so you can detect any issues before they shut the system down when you least expect it.

2. Always presume the problem is the flow of the water unless you can see that the flow of the water is adequate.

3. Should you discover ice particles on the coils, you have a coolant leak, call a marine air specialist.

4. Feel the water from the outflow. It ought to be slightly heated. Scorching water signals some obstruction somewhere in the reverse cycle system.

5. Inspect the in-coming through hull initially and clear obstruction by utilizing a water hose; you might also utilize a compressed air horn.

6. After that, be certain the sea strainers are free from debris. I inspect mine every month based upon previous experience. You might find you should look at your sea strainers more often or less based on the quality of the water your boat is in.

7. On occasion, I recommend you detach the hoses leading from the through hull to the pump; these hoses will get obstructed with algae and mud occasionally.

8. Lastly, flush out the complete HVAC system by using the dock water hose on full blast, put into the hose that you took off from the in-coming sea cock. Keep the system switched off while you are doing this. Have someone watch the water flow on the outside of the boat and inform you when it runs clear. This may appear pointless but what occurs is that residue remains in the lines over a period of time, preventing correct heat transfer. Purging the lines will greatly improve the functioning.

9. Lastly, place roughly two bromine pellets into the sea strainer basket prior to closing everything up. If utilized in sea water, clinging critters and barnacles will not live in this water.