Maxum 3000 SCR Air Conditioner - Maxum Boat Owners Club

jayesq · 07-25-2011, 07:32 PM

I have a 1999 3000 and the fan on the airconditioner seems to work only intermittently. It is the Marine air vector compact model. When you first start the unit fan comes on and everything works fine, after a period of some time the fan stops working before the set temperature is reached. I shut off the sytem for a few hours and it started back up and the sytem worked fine and then the fan stopped again. I checked to make sure i have sufficient dishcarge and that seems fine also. Any ideas or thoughts would be appreciated.

Thank you,

seapuppy · 07-25-2011, 08:54 PM

it sounds like the unit is icing up..when that happens..the unit will shut down the fans to keep it from damaging itself....

you can try cleaning the fins on the heat exchanger...and have it serviced by a tech to check the coolant levels in the system....low freon (or whatever their using now) will cause icing....

Sp

jayesq · 07-25-2011, 09:29 PM

seapuppy

Thank you for the info, I guess that could explain why after it sits for a while it works again. Do you know the best way to clean the heat exchanger? Do you just vacuum it out. I guess I should also make sure the filter is clean as well? We had some extreme heat last week maybe the system couldn't handle the temp and humidity.

seapuppy · 07-25-2011, 09:35 PM

check on the forum here...we're actually having a good discussion about that very same thing.......one individual did a full up cleaning and explains it......
http://www.maxumownersclub.com/forum...3052-AC-freeze

oh..and welcome to the zoo..

SP

jayesq · 07-25-2011, 09:44 PM

I will check out that discussion. Just to clarify one issue. When the fan goes off the control panel stays on and the raw water pump continues to pump water through the system. Thanks.

biggerseagar · 07-25-2011, 11:14 PM

Jayesq...........I have been going through a bit of discovery about how to operate my marine air the last month, even though I have had our boat for four years.

First.......get a quaified HVAC repairman to look at your unit. The money spent will be well worth it. I hope you have read my ac freeze thread and sort of gotten what was going on with my ac unit. The marine air manual explains alot of do's and don't. But..........Get somebody to look at it before you do anything.........

Mine was a simple fix and it has worked fantastic so far!..........good luck and let us know how it comes out........

Roger

jayesq · 07-26-2011, 12:12 AM

biggerseagar

Thank you for the advice. I always like to try to get some info before I call the tech's just to make sure everyone is being honest. I thought maybe someone has been having a similar experience. When your unit freezes up does it shut down or does the fan shut off?

biggerseagar · 07-26-2011, 01:10 AM

It did neither...............The fan would still run but that was it...........no cold air. The compressor would shut off.

I would get icing on the bottom of the fins and then around the tubes that when you open the air vent you see them.

I don't have any experience in a/c so it was great to get my tech over and we figured this out..........and again good luck...

lynn · 07-06-2015, 07:16 PM

We have a 1999 3000 scr and the A/C does the exact same thing. The until gets all icy and stops blowing cold air. If I try to turn the fan up it will trip the circuit breaker. Turn it off and let it thaw then it works again for a while.
Boat is new to us so we haven't had a chance to start working on this issue. I just figured out how to flush the toilet. Next, I need a lesson on using the garmin. As soon as I think I have it figured out... I find out I don't. We learn new things everyday!

Kevlar7r · 07-07-2015, 01:16 AM

Lynn, that is low Freon in the ac unit. It is r-22, so you will need a licensed AC tech to check it out. Your local marina should be able to recommend someone, but any home AC tech can top it up.

CGG · 07-07-2015, 01:32 AM

First, make sure the filter is clean. You can buy these at the hardware store. Next, when you start the unit set the temp at 72. Too many people set it as low as it will go and the unit will just freeze up. Bring down the temp gradually. I have my fan set to A (automatic) and the unit works great. Have to keep your door shut as much as possible. Constant opening and closing or leaving open for a few minutes will make the unit work too hard causing it to freeze. If the unit does freeze, reset the temp above the current cabin temp and the unit will turn off the compressor and it will thaw out the fins. Once thawed out (a few minutes) reset the temp lower.

Kevlar7r · 07-07-2015, 01:37 AM

CGG, the only thing that causes an R-22 system to freeze is low Freon. You tune the Freon volume to keep the low side temp around 40-45 degrees. Regardless of what temperature you set your thermostat to, the unit cools the evaporator to the same temperature. Thermostat controls the cabin temperature by adjusting how long the unit runs, not by changing its temperature.

The same is true for all package refrigeration units, such as your house.

biggerseagar · 07-07-2015, 01:27 PM

It is the design and placement of the A/C unit in the boat that is the cause of the icing IMHO. The unit is sideways from the air vent. The fix is to bring your temp down at 3 or 4 degrees at a time so if there is icing it can recycle for a little while, then turn the temp down another 3 or 4 degrees until you get where you what it. Set the fan on 6 the highest will also get the best results. Mounting a small fan for air circulation to prevent icing in front of your condenser would help also.

Hope this helps.

Roger

pgp · 09-10-2015, 05:57 PM

Icing in any refrigeration system is always a case of low refrigerant. Get your system topped off by any HVAC repair dude....

lynn · 09-10-2015, 08:02 PM

That's what we did, no problems since then. This heat has been a good test.