A/C Not working

Tim Brouse

New Member
Apr 13, 2022
Boat Info
2004 260 Sea Ray Sundancer. Garmin Echomap plus chart plotter.
2018 Mercruiser 5.0 MPI 300hp. Bravo III drive.
I have a 2004 260DA Sundancer with Crusiair for air conditioning. I am not getting cooling or heating. When I bought the boat 2 years ago, the A/C at the sea trail worked. The thermostat works fine and the blower works fine. The Sea strainer is clear. The seacock is open and clear. I am not getting any flow from the starboard drain. I removed the hoses on the inlet and output of the water pump to clear any blockage and to verify it is working. Plenty of pressure on the output side. I flushed the water line, with a garden hose and nozzle, from the pump out to the starboard drain and vice a versa. Found debris from bugs and now have good flow but when I run the A/C, no water comes out. Checked the A/C unit and have a little frost on the low pressure side pipe so I must have Freon in the system. I have not put gauges to the unit since I don't have any. Any ideas? Also, how long should it take until I should feel cold or warm air. I have run the systems a couple of minutes. Didn't want to run it too long in fear of damaging the system. First time post here. Thanks. Tim.
The A/C cooling water pump only turns on when the A/C compressor kicks on, pump will not run with compressor off (even if the A/C unit fan is running). There is a relay in the A/C control unit that completes the circuit to the pump.
If you have removed all debris from the water lines and verified that the pump works, then most likely the relay is bad.
I can almost guarantee your air conditioning pump is air locked and needs priming. Many of us have been through this situation. Whenever I've lost water prime to my AC pump I attach a submersible pump in a bucket of water, attach it to the hose that leaves your AC strainer, have someone turn on the AC upstairs and....there you go, prime is re-established! Now have your upstairs friend turn off the AC, you reconnect the strainer (without letting air back into the line) and you'll be good to go.

FYI...prime can be lost whenever you open the seastrainer with the air conditioner pump running, or when the boat has been on dry land or for a bunch of other reasons.
The key thing I read in your post is that you still do not have flow. Brewster is on point. Another method you could try is to back fill the system from the thru-hull exit on the side of the boat. Water is heavier than air so it should displace the air by the pump.
Thank you all for your responses. Gallf1, I will check the start relay.
Electricaldoctor, I will check the starting capacitor since I will be right there.
Brewster16 and Lazy Daze, I will try filling the water line. I don't have a submersible pump so I will have someone back fill from the thru-hole, wait for solid flow and reconnect the line to the pump.
The thing that was not mentioned here is, is the compressor actually turning on? I am assuming it is since you mentioned frost on the low side. If the AC pump is not turning on with in thirty seconds of the compressor turning on. Then verify that power is being placed on the pump line. Put your meter on the pump terminals of the AC control board.
Thank you all for your responses. Gallf1, I will check the start relay.
Electricaldoctor, I will check the starting capacitor since I will be right there.
Brewster16 and Lazy Daze, I will try filling the water line. I don't have a submersible pump so I will have someone back fill from the thru-hole, wait for solid flow and reconnect the line to the pump.
With the example I provided, you don't need to remove the line to the pump. Just backfill - the air should burp out enough for the pump to get a good suction going. It's easy enough to try that first, anyways. Fill from the outside at about a 1/4 of the normal hose flow.
SKbolt, I have verified there is power. Thanks.
Lazy Daze, I was thinking either open the top of the sea strainer and verified any air that might escape or open the sea cock valve and watch for steady flow. My boat is on a trailer. Thanks for the suggestion to run the water at a slower rate. I have been running it on high flow to clear any obstructions.
Tim, the suggestion to only use 1/4 flow was only because it would probably backfill the line more efficiently. You're fine with flushing at full force.

Oh, you're on a trailer? Hmmm... the force of the hose coming through the fake-a-lake should be plenty to fill the strainer and give the pump plenty to get going.

Try this... with fake-a-lake hooked up and hose on full bore, open the sea strainer till it fills, then close the lid. Then go ahead and turn the system on.

Or... instead of a fake-a-lake, are you using a sea strainer lid with a hose attachment? That's fine - but be sure the seacock is closed.
Update, Looks like it was a air lock. Kind of. Ran water from the outside drain slowly and then filled it from the output side of the pump when I disconnected the hose from the pump. Turned on the heat. I could feel the compressor running and heard a different sound. Reconnected the hose and ran water into the strainer and got water to come out the drain hole. It started draining decently but slowed to a amount 1/4 of what it had started at. It was 48 degrees outside so didn't even try the A/C. I got heat. I got 75 degrees on the a handheld thermometer. I let it run for about 10 to 15 minutes and then the water stopped coming from the outside drain and the temperature dropped from the air vent in the cabin. Checked the unit and found frost on the pipes as you see from the pictures. boat AC frost.jpg boat AC frost2.jpg Not sure how much frost is normal. These were taken a couple of minutes after I turned it off. The blue cap did have ice on it. I am wondering if the pipes froze up on the inside and that is why water is not flowing. 2nd Update! While writing this I let the unit defrost and ran it again. Water flowed and got the air temp from the vents up to 94 degrees. Yeah! 15 minutes later it froze up again and no water flowing out. Defrosted again and water flowed and got heat again. My wife stood outside and noticed the water flow every couple of minutes would go full stream for a second then back to a dribbling out the drain. I watched it and it did the same thing. 15 minutes later no flow. I now suspect it is the water pump. Even though it flows water, it is not pumping enough water to keep the pipes full, which would allow them to freeze up being only partially filled. I saw a video of someone replacing their pump and saw a solid stream coming out the drain. What do you all think?
@Tim Brouse Before you go changing the water circulaiton pump, I would check the "freon" at the compressor with AC gauges. Typically, when AC units freeze up it is due to an insufficient amount of coolant in the compressor/evaporator/condenser loop. What is happening (assuming in AC cycle) is that the pressure after the expansion valve is too low causing too much refrigeration, the temperature is going below 32 Deg F. The frost is the humidity in the air freezing on the coils. Our units on the boats are essentially heat pumps, so in heat mode, the cycle is just reversed (very simplistic explanation).

Jaybeaux, thanks. I wonder, if the coolant is low enough in the loop, would I get a low pressure warning on my thermostat? I have never got a LO-PS or HI-PS warning on the thermostat while I ran it the last time. My manual states any PSI below 30 and the system will shutdown and resets at 45 psi. Which it never did. I guess the only way to be sure is to check the pressure. I am going to get a set of gauges and read the pressure and then decide if I need a mechanic.
The first chance I will get will be next week. I will let you know. To be continued...
I would suspect that frost would build before the alarm. Just my opinion.
General rule of thumb, freezing coils are caused by:
1. Low charge
2. Restricted air flow over evap coil (ie: blower not blowing as designed, closed vents and / or dirty filters)
Update! Today was warm enough to work on the boat. 25 degrees at night here in NC along the coast is too much. Put a set of A/C manifold gauges to the compressor and got 50psi on the low side and 75psi on the high side. Turned on the A/C and both gauges dropped to 0. I think I found the problem!
Brewster16 sorry but the filters are all clean. Bill and Jaybeaux you called it. Thanks.
I also disconnected the inlet and outlet hoses from the compressor to much sure the water lines were clear, which they were. I blew air through the compressor coils to make sure they were clear. I got good air flow. Removed and cleaned the Sea Strainer and replaced all the gaskets. Checked the inlet opening on the cap to the Sea Strainer and it was clear. Still trying to figure out why I have such low flow of water out the thru-hull fitting. I might have to replace the pump. I will check with the mechanic and see what he thinks.
Ok, so its off to the mechanic to get the unit evacuated and recharged. This is a R22 unit, originally, and I don't know if it has ever been updated. Might as well start fresh and have it done right. I appreciate everyone's help and will let you know what the outcome is after I get it back. It may take awhile but I will keep you updated. Thanks.
Glad to be able to assist. You are welcome
Update! The A/C IS WORKING. I put a set of refrigerant gauges on the unit and found it had only 50psi not running and 0 running. "There's your problem". I called around to the local marinas to find a mechanic who does A/C. Turns out, in the Southport NC area, there is none. One marina did have someone but he went to work for a HVAC company. Looked some more but to no avail. We are having a split A/C unit installed in our house, so I talked to them and they said they could do it. Told them is was a R22 system. They said no problem. They still have some R22 and the approved substitute. So no having to evacuate the system for the new stuff. Saved some money there. The process took about half a hour. He said he probably only used about 5oz but what a difference. Total bill will be around $200. Well worth it to have heating and air conditioning again.
Had to come up with a fake a lake. View attachment 141817 The picture is sideways. Let me know if the picture didn't come thru. Used 1/2 threaded pipe nipples, couplers, rubber gaskets along with plexiglass as a cap. Made it from off the shelf parts. The plexiglass I already had. Spent about $22. Probably never need it again but I am not throwing it away. It worked perfectly. Had water flowing out the side of the boat the way it should be. On a previous post I thought the seawater pump was bad. Checked it out and it was fine. I realized the pump is not self priming and the light bulb went off. Need pressure to get the water to the pump and it takes over from there. Duh!
Thanks for everyone's help. Got to love these forums. Tim.

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