My 2000 Catalina 36 has factory installed Marine Air System Passport ll 16,000 BTU AC. Have washed fresh air intake filter, filled coils with vinegar (letting sit for one week) to loosen any possible calcium deposits), bled the Venturi valve for any air bubbles, took out raw water filter and cleaned it. Air vent under port cabin window feels cool but not super cold. Made sure not getting iced up. Water definitely discharges out the port side but not as vigorous as other boats in the marina. Checked water intake & discharge for obstructions (zebra mussels) & found none. How vigorous is your water discharge? Should I consider replacing the factory installed raw water approximately 4" long raw filter with longer water filter jar & strainer? Would you recommend getting a larger capacity pump? Dock neighbor with brand X sail boat, same size as ours has 580 gallon per hour pump and has strong discharge. (I can't find what my OEM raw water pump gallon per hour capacity is). Suggestions would be appreciated.
peter g
2000 C36, MK2, Hull. #1897
wonderful, wonderful, wonderful ! ! !. 5 th Catalina
If you have the condensator from mermaid, disconnect it and give it a try. Put it on my unit and it restricted the water out flow tremendously, would like to use it but on system other than mermaid caused more problems than it was worth. Go outside and measure out flow in a bucket. Mark bucket with I gallon marks and time for a minute, multiply by 60. Then disconnect condensator and do again you should see significant difference. If still not could enough think about a refrigerant recharge. Chic
I had a similar issue on my two Mermaid units The water leaving the boat was much less compared to my neighbors, especially for the forward unit. The aft unit discharge was probably at 40% and the forward unit discharge at 20%.
First, I checked the strainer and found nothing.
Next, I removed the plumbing attached to the exit of the raw water pump and used a garden hose with some flexible hose attached to the end to flush out the lines running from the pump to each a/c unit and out of the boat while the Admiral observed from the dock. She reported that silt and other gunk came out, but nothing that alarming.
A neighbor who lives on his boat in the slip next to me mentioned that at this time of year in Miami, he needs to flush out the line from the strainer back to the seacock every few days. I took the garden hose and snaked the flexible hose attached to into the strainer where water enters from the seacock. I shot a few blasts of water in there and immediately noticed the flow of water into the boat increase from the seacock. I closed the seacock and put everything back together.
Finally, I reopened the seacock and primed the system by powering up the a/c to engage the raw water pump, but turning it off just before the fan and compressor engaged on the a/c units. I repeated this 7 or 8 times before leaving it on for good. Needless to say, water is now exiting the boat like my neighbors.
I think the main problem was that I had some gunk on the bottom blocking the seacock...my bottom cleaner will be getting a call this week! There is no doubt, however, that flushing out the lines from the pump to the units and out of the boat helped too. Mermaid suggests flushing the lines once per year.
Hope that helps!
Matt
Matthew Becherer
s/v Constellation
Catalina 36 MKII, #2104
Wing Keel, Standard Rig, Universal M-35BC
Miami, FL
Hey, It Works!!! Marine Air Systems Passport 2,16,000 BTU on 2000 Catalina 36. Sailed in Lake Michigan & Upper Mississippi River. This the season to get this thing going! Below is my learning curve and now works on my boat. Some of these suggestions are obvious, but might get overlooked.
1) Do you have healthy water discharge? Check water flow system, from water intake to water discharge for obstructions (zebra muscles might be clogging hoses, valves, screens, fresh water filter filled with algae). You might have to ream out hoses for obstructions.
2) The heat exchanger, aka evaporator coil) water flows through a box with filled with a copper pipe, surround by freon), air is drawn by the blower over the fins of the evaporator. Heat from the air is transferred to the refrigerant (freon or similar). The heat is transferred to the fresh water and heated water discharged. Hope your coils feel really cold. If you have your windows and hatch covers open, you will only invite too much moisture in and you CAN freeze up the copper pipes -if you freeze up, there is a defrost cycle on control panel for the heat exchanger. You will never cool the boat if you are inviting hot humid air to easily enter cabin. Close boat up, hopefully you have a hatch cover alternative - my boat came with zippered hatch cover, snaps in place, with clear plastic flexible plastic window material.
3) if your boat has been in high mineral content waters, there could be a calcium build up in heat exchanger. Disconnect both upper and lower hoses for heat exchanger. Plug discharge pipe with 24" clear hose and insert funnel to other end of hose. Raise funnel above the top of heat exchanger and Pour vinegar in the funnel until it comes out the heat exchanger on the top (muriatic acid or lime away scares me - vinegar is much less toxic to the environment and your hands). Secure funnel end so it remains above the top of heat exchanger and let the vinegar sit for a day (or a week). Vinegar will dissolve any calcium deposits in the exchanger.
4). One reason your AC system might not be working is because there may be air bubbles somewhere in the water lines. My set up has a small valve on the discharge side of the pump (between the pump and the hull) that allows me to discharge a small stream of water for a few seconds to purge any air bubbles out of the system (yes, the fresh water hull valve must be open).
5). Make sure return air grill next to the heat exchanger (in the cabin) is clean. The return air grill will be at floor level in the main salon. You should vacuum it or wash if possible with fresh water. Cat and dog hair stuff these grills up.
6) Make sure the cold air grills in all cabins are un obstructed (yes, this past weekend a family member conveniently put a book or magazine covering the grill.
7). Read your manual or download and keep printed copy on board.
peter g
2000 C36, MK2, Hull. #1897
wonderful, wonderful, wonderful ! ! !. 5 th Catalina