Maintenance

Reversing Valves

Reverse cycle units have a reversing valve; the valve must be energized periodically to keep the internal parts moving freely. To do this, switch the a/c unit into heat for a few seconds once a month.

Seawater Strainer

Insure that your pump receives adequate seawater flow by regularly cleaning the strainer basket. Periodically check the overboard discharge for a steady stream of water. Check seawater intake speed scoop for obstruc- tions. Make sure hoses are not looped, kinked or crushed.

Condenser Coil Cleaning

1.With the system turned off at the circuit breaker on the ship’s panel, disconnect the inlet and outlet connec- tions of the condenser coil.

2.Use chemical resistant hoses (MAS white PVC 5/8” I.D., etc.) to connect the inlet of the condenser coil to the outlet of a chemical resistant, submersible pump (MAS P-500 pump, etc.) and let the hose connected to the coil outlet flow freely into the container mentioned below.

3.Place a strainer or piece of screen over the inlet of the pump and submerse the pump into a container filled with a 5% solution of muriatic or hydrochloric acid and fresh water or use a premixed over-the-counter solution. Use a large container as possible to hold the solution (5-25 gallons).

CAUTION: Avoid spilling or splashing the solution. Follow all warnings and recommendations given by the manufacturer of any acids or premixed solutions.

4.Power the pump and circulate the solution through the condenser coil for 15-45 minutes depending upon the size of the coils and the extent of the contamination.

Visual inspection of the solution in the container should indicate when the contamination removal has stopped.

5.Circulate fresh water through the coil to flush any residual acid from the system.

6.Restart the system and check operational parameters to ensure thorough cleaning has taken place. Addi- tional cleaning may be necessary with extreme contamination.

WARNING: For the purpose of protecting the environ- ment, dispose of any contaminated acid solutions in accordance with federal, state and/or local regulations.

Return Air Filters

Check the return air filter about once a month and clean as necessary. To clean the filter, remove it from the unit, rinse with water, air dry and reinstall.

Winterization

There are several methods of winterization, some of which work better than others. The four various methods employed using a 50/50 nonpolluting biodegradable antifreeze/water solution are:

1.Pumping of antifreeze solution into the overboard thru- hull fitting, and discharging through the intake thru-hull fitting.

2.Use of the seawater pump to pump antifreeze solution through the system and discharging through the overboard thru-hull fitting. Close sea cock, remove hose from strainer discharge, raise hose above pump (so pump does not lose its prime) and pour in anti- freeze solution. Pump solution through system. The strainer and hose to sea cock will also need to be drained of water.

3.Use of pressurized air injected at the overboard discharge fitting and the water being discharged through the seawater intake fitting.

4.Use of pressurized air to force water from the intake through the overboard discharge.

Any method that causes the antifreeze solution to flow downward is the method of choice. By this means, the antifreeze solution will displace any water trapped and eliminate the possibility of freezing in hidden areas. In addition, since the seawater pump utilizes a magnetically driven impeller, the impeller should be removed from the wet end assembly, wiped with an alcohol solution, and stored in a warm, dry area until commissioning takes place.

Note: Collect all discharged liquids and re- cycle or dispose of in a proper manner.

L-2254 Maintenance	15	❖ English