AC freeze - Maxum Boat Owners Club

biggerseagar · 07-18-2011, 02:42 AM

Hi Maxum folks

Hope everyone is having a great summer so far. The admiral and I are doing great.

My question is......... ever since we have had our 2001 3000 SCR when the temps get into the high 90's my AC will freeze up. This is when it has to run along time and doesn't get to cyle off. The condenser gets a nice sheet of ice on it and then I shut it off and let it melt. After that it works fine.

If the unit doesn't cyle back and forth once it gets to it the temp setting I have this problem. Temp was high 90's today and had the ac set at 80.

I am going to give the condenser blades a good cleaning tomorrow and see if that helps. Nothing is blocked as far as air flow goes. Our unit is underneath the forward bed and I wonder if I remove a plywood divider that would help with the condenser circulation?

Two years ago I have had it checked out by an so called ac expert at our marina and said that I was not low in freon but had a bubble of some sort in the system. ??????

Any thoughts from any of you HVac experts out there in maxum land?

Roger

seapuppy · 07-18-2011, 03:09 AM

well...that is just wrong...especially since I don't have a boat...however....your AC freeze up is usually due to low freon...or not enough air flow over the fins of the exchanger...try turning your fan up on high..see if that doesn't change the freezing problem..

SP

biggerseagar · 07-18-2011, 03:22 AM

Thanks SP.......... we all hope that you and your admiral get your summer turned around for the better. This problem of mine is a pin prick compared to what you have gone through!

I am going to bring down a portable air compressor and blow the fins out to see if that helps.

Roger

brianbossman1 · 07-18-2011, 03:27 AM

Seapuppy has it on the nose, low freon and /or dirty coils. Clean her up first and see how she does. Good luck!

biggerseagar · 07-18-2011, 04:30 AM

Thanks guys..........I'm cleaning the coils tomorrow, then calling my hvac friend.

tackleshep · 07-18-2011, 02:53 PM

One other piece we experience here is hotter than hell land. Make sure the boat is sealed tight. If I leave a door or port open and run air conditioning the condensation will freeze it in a heartbeat.

biggerseagar · 07-18-2011, 05:39 PM

Thanks TS.......

That got me thinking (which is dangerous) I don't have a door vent on the head door so we keep a small fan going on the ledge in the head and then we open up the bathroom window and I blow all my stinky air next door toward my neighbor slip. (nice guy huh?).....It keeps the bathroom much cooler from if I did nothing. I wonder if that has anything?

tackleshep · 07-18-2011, 05:48 PM

I do that as well but keep the door shut. My buddy a couple slips away has to "step down" his air. (So if it's 90 in the cabin he goes to 85, then to 80, then to 75) and once he's there it's ok. Anything else and it freezes over. He definately needs a charge.

For me it's only when we have good humidity and the rear window, port hole, or door is left open she freezes over. I then turn on the heat for 10 minutes and defrost, close everything up and go from there. I have no other problems......sounds like that charge check is necessary for you.

biggerseagar · 07-21-2011, 04:37 PM

Well an update...............bought a can of Evap foam ( condensor fin cleaner) and a fin cleaner brush. Did the business on the fins. Clean as a whislte. While in the cabin...temp read 100 degrees. Turned on the A/C got it down to 96 within an 30 minutes. Getting late in the evening so took off. I am having the freon checked next week.

Thanks for all the help!

Roger

tackleshep · 07-21-2011, 04:57 PM

you still need freon. My cabin shows 100+ degrees and in 30 minutes will be in the low 80's to 70's.

biggerseagar · 07-21-2011, 05:43 PM

Kinda thought that.....

shrew · 07-21-2011, 05:57 PM

The other thing that I've read can lead to the coils freezing is poor coolant flow. The coolant is, of course, raw water. I've heard that the raw water cooling system needs to be peridically flushed and descaled. saltwater might be barnacle and salt deposit buildup. In any environment, possibly mineral buildup (lime, etc.). If freon doesn't do the trick, I'd start looking at this as well.

biggerseagar · 07-21-2011, 08:19 PM

Shrew...........I downloaded the Marine air PFD booklet and that was in there also. You use a solution of muractic acid to do this. Boat came from Lake Michigan and I'm on the Illinois River so I hope that is not an issue.

shrew · 07-21-2011, 09:23 PM

Yes, I try to keep in mind that not all boats are in saltwater, and thought that when I saw you are in Central Illinois. Though it never hurts to toss it in there for other's with similar issues. I doubt it is barnacles in your case. Though i understand zebra mussels can be an issue. I'd more suspect mineral deposits like lime to be a potential culprit. Heck, mineral deposits have completely clogged my Keurig coffee maker more than once and I only use tap water. If the freon doesn't do it, then descaling should fix the issue. nothing like an A/C issue in the middle of a heatwave. ARRGG!!!

biggerseagar · 07-21-2011, 10:35 PM

Wife had to clean our Keurig out last night............and all we use in it is bottled water...........but thanks for the info.

Knowing this strange weather we will have a cold wave in August??????

dronthelake · 07-22-2011, 02:12 AM

Being in construction I have dealt with HVAC contractors for years. They all have said that a a unit only gets low on freon if there is a leak. That AC units do not consume freon.

shrew · 07-22-2011, 01:26 PM

Quote:

Originally Posted by dronthelake

Being in construction I have dealt with HVAC contractors for years. They all have said that a a unit only gets low on freon if there is a leak. That AC units do not consume freon.

Very true. I learned that the hard way on a car a few years ago. I wanted to have the system recharged and my mechanic basically told me the same thing. The A/C replacement was worth more than the car and it was the middle of a heatwave. I traded the car in. I believe an HVAC guy should be able to do a pressure test to determine if there is leak in the system. I would think that would be a good first step. I'm thinking that he may also be able to help with the descaling of the system as well. IT might be time to bring in a pro for this one.

biggerseagar · 07-23-2011, 12:29 AM

Well it was an interesting afternoon........I met my Hvac guy at the marina around 2pm and he checked the marine air unit out. NO LEAKS! Freon is OK. Told him all that I had done, clean this and that and said great. The air temp was 59 degrees coming out of the main cold air outlet. Put the paper towel up to the cabin vent and sucked it right on. Thumbs up!

He didn't like or didn't think there was enough air flow going through the coil when he put his hand on it, but still he thought nothing definite in the wrong dept. He also thinks that the fan was on low (1) and that might of caused the icing. He also said that there might be an air imbalance, with all this air coming in and not enough going out (cold air) He suggest that maybe put another cold air outlet in the boat and run along the portside edge under the bed compartment. When he was all done he gave it a clean bill of heath. Fantastic. $40.00

The plywood divider that is in this compartment underneath the cabin bed next to ,the AC unit, I took down two days ago so I could spray the Evap foam and clean the coil fins. This piece of plywood was running along side of the coil face about 3 or 4 inches of room. My friend that was with me this afternoon suggested that I put the divider back up but find a 12v fan that I can attach to the divider and point it toward the coil to help with the air flow. My Hvac guy like that idea.

So back to square one with all this.

An after thought.......I would really would like to kick the person in the nuts a couple hundred times that wrote the Marine air program quide. Even Hvac guy was laughing while reading all that crapola. Give me a 2 by 4 instead.

Just another day of boating

Roger

biggerseagar · 07-25-2011, 04:59 AM

We had the a/c running and set on 79 all day saturday, throught the night and sunday morning without issue..........worked great.

One thing that I did read in the manual was that if the water temp is 90 degrees or higher the unit will struggle to work cooling the air. The Illinois river water temp has been right around 90 degrees........but as I said before it work great without freezing up. Fingers are crossed!

Roger

dronthelake · 07-25-2011, 02:48 PM

If you have to add freon then you have a leak. Freon is in a sealed environment and is not consumed during operation. If you have to add freon make sure you fix the leak or you will be adding it again. Our units are 12 years old and we are very fortunate that they have not needed any repairs. When we leave the boat on Sunday evening we raise the temp on both units to 78 and let them run all week. When we arrive on Friday I set the front unit to 75 and the rear to 72.

This past Saturday it got to 97F at the lake. That morning while out on the lake I shut both units down around 10 AM. I kept all ports, hatches and the cabin door closed. For the 3 round hatches and the oval skylight I insert fitted pieces of foil covered car windshield sun screens. The highest the interior got was 82. When I turned the AC back on around 8:00 that evening it took less than 30 minutes to cool back down to 72.