Might have A/C fixed.....but

[tawcat]

what will happen if I let the unit run while frozen?

We think we have our problem is fixed, however, the unit ran non-stop for like 14 hours and then it froze up. I switched to heat for a few minutes and when it thawed I switched back to a/c.

Left the boat this afternoon, set the temp at 85 and keeping fingers crossed. I'm thinking that if it freezes eventually the unit will shut itself down. Am I right or do I need to go back and just shut the thing down?

Arkansas right now is hitting high 90's to 100 degrees, heat indices well over 110. So when we get back to the boat next weekend, we'd like to have it a bit cool.

Am I looking at buying a new system? How long to these units last? Heck it's an '05, surely it's not due for a new unit yet!

Thanks for any advice, tips, hints or criticism

 

[tobnpr]

What size unit did SR install? Sounds like your unit is working constantly but not getting it done...

While the 90's are pushing it, it's important that there be adequate BTU's to handle that kind of heat load. Nowhere is worse than here in FL- but I have no problem getting the temps down to 75 in the cabin right now, and it was 93 today with HI of 105. Two units putting out a total of 25,000 btu's. I think a 320 needs a 16K unit to be able to handle that kind of heat load.

Other things help- like keeping curtains drawn and sunbrella covers for your hatches, they really cut down on the heat gain in the summner.

 

[tawcat]

What size unit did SR install? Sounds like your unit is working constantly but not getting it done...

While the 90's are pushing it, it's important that there be adequate BTU's to handle that kind of heat load. Nowhere is worse than here in FL- but I have no problem getting the temps down to 75 in the cabin right now, and it was 93 today with HI of 105. Two units putting out a total of 25,000 btu's. I think a 320 needs a 16K unit to be able to handle that kind of heat load.

Other things help- like keeping curtains drawn and sunbrella covers for your hatches, they really cut down on the heat gain in the summner.

Exactly what my a/c guy said. It's got a 12k unit and he says it needs a 16k.
Weird thing i this is our third season and this is the first season we have encountered problems.

 

[firecadet613]

I've heard you can get build up in the lines and can be cleaned with an acid? Don't quote me on that, as I'm still searching to find out. My 5000BTU system had a tough time this weekend. It's in the 90's here...and it wouldn't get below 81, but we were in and out of the cabin.

 

[tawcat]

Well I think that happens with us as well. Cabin door opens and closes. So who knows!

 

[tobnpr]

Depending on how big an issue this is for you, you might consider upgrading to a larger unit, and selling your current unit on Ebay.

Good possibility that a 16K unit would take the same size duct and might be an easy swap-out if the unit's accessible. No other mods should be necessary, perhaps a larger breaker but I doubt it. If access isn't an issue, A/C swap-outs are very simple- especially if you stick with the same manuf and can keep the original controls. Takes less than hour.

 

[kg4vgh]

might also check for air restrictions in the return.....if the filter is dirty it will restrict the air....which in turn causes freezing.....mine is a reverse cycle...so cooling and heating is dependent on water temp.....I added a stand alone upright this year (14,000btu) and it is working well...getting close to the same temps that you are.....so far...it's maintaining....I believe my AC is the originial...so it's 20 years old....time to replace....

 

[tawcat]

might also check for air restrictions in the return.....if the filter is dirty it will restrict the air....which in turn causes freezing.....mine is a reverse cycle...so cooling and heating is dependent on water temp.....I added a stand alone upright this year (14,000btu) and it is working well...getting close to the same temps that you are.....so far...it's maintaining....I believe my AC is the originial...so it's 20 years old....time to replace....

Thats my thought, 5 years is much too early to be thinking replacement. But, if thats what it takes than thats what we'll do.

 

[billnpat]

What size unit did SR install? Sounds like your unit is working constantly but not getting it done...

While the 90's are pushing it, it's important that there be adequate BTU's to handle that kind of heat load. Nowhere is worse than here in FL- but I have no problem getting the temps down to 75 in the cabin right now, and it was 93 today with HI of 105. Two units putting out a total of 25,000 btu's. I think a 320 needs a 16K unit to be able to handle that kind of heat load.

Other things help- like keeping curtains drawn and sunbrella covers for your hatches, they really cut down on the heat gain in the summner.

We have on our 2002 310 MFG Cruise Air 10,000 BTU's reverse cycle .

and i have to shut it down after a while because it gets so cold in the cabin...after shutting down it stays cool for hours..
i have the fan on low and temp at 65-70 all shades drawn and cabin door closed, we did clean all filters and vacuumed out the intake grill near the bunk..
isn't there a thermastat on the unit...:huh:.

 

[tawcat]

billnpat: Yes there is a thermostat, but for some reason, who knows, the cabin just doesn't reach the set temp. And again it could be just due to water being so hot.

Here is my original question (at bottom) and the response from CruisAir:

Stan,

It sounds like you're doing everything correct. Usually, a unit freezing up in the cool mode is caused by air flow, or refrigerant. If the refrigerant gets low, the pressures will run low, causing it to freeze, as well as air flow. The pressures will drop.

If you've already checked the filters and the coils, what you can do is run the unit w/ out the discharge duct work hooked up to the unit. It could be some kind of restriction in that causing it. Disconnect that and run it for a while. If you no longer experience the icing, then the duct work may have to be checked or re routed.

Tx.

Jacob Prince
Administrative Service Technician





Joann Brown/Richmond/North America/Dometic
06/28/2010 08:31 AM
To Jacob Prince/Richmond/North America/Dometic@Dometic
cc
Subject Fw: From Www.cruisair.net, To service






Jacob,

Could you please help this owner out with this unit that is freezing up.

Thank You

JoAnn Brown
Warranty Administrator
Dometic Corporation
Environmental Division
Phone - 804-746-1313
Fax - 804-730-6781
email - joann.brown@dometicusa.com


----- Forwarded by Joann Brown/Richmond/North America/Dometic on 06/28/2010 08:30 AM -----
Cruisair Contact <sales@cruisair.com>
06/27/2010 09:35 PM
To service@cruisair.com
cc
Subject From Www.cruisair.net, To service









Mr Stan

address 1:
address 2:
AR 72207
USA


Information:
What size boat do you own? 32 ft
What model is it? 320 Sundancer
What make is your boat? Sea Ray
What year is your boat? 2005

Do you currently have Air Conditioning on your boat? yes

Do you currently have Refrigeration on your boat? yes

Customer comments:
We have a 12k unit on our boat. Recently the unit has begun to freeze up. We've had freon checked; filters are clean; and we've cleaned the coil.

Arkansas is experiencing temps of high 90s to 100 degrees. Water temp probably 80. Unit just never gets to set temp before freezing. When it freezes I switch to heat to thaw it; then set unit about a degree below cabin temp. Then it seems to cycle on and off normally. However cabin temp is still in high 70s or low 80s.

This is our 3rd season with this boat and this is the first time weve experienced problems. Any suggestions Is there something Im doing right

Thanks so much.

Stan

 

[Windjammer]

Usually inadequate air flow over the condenser is the main cause of a unit freezing up. Start with the simple things first. Remove and clean/wash the filter. With the filter out, vacuum the area where the unit is located and the condenser fins. Home Depot sells a non-corrosive coil cleaner for about 10 bucks. With unit off, spray on the fins and let it set for about 10-15 minutes. This will loosen the dirt and grime the filter misses. Start the unit back up - the condensation water will rinse the cleaner out of the fins.
Assuming you have a strong flow of water from the thru hull. If not, check raw water strainer basket and the raw water pump impellor for broken/missing vanes. Again these are the relatively simple things to check first.
If problem still exists, might want to have the freon level checked and a leak test performed.
I would not leave a unit running while frozen as it may damage the compressor.
If you decide to replace with a 16K BTU unit, you may have to add an additional return duct.
My unit had to be replaced this year as the previous owner had some problems and used a cheap compressor. New unit is a Cruisair STX12-410(A) and works great, plus it will work with existing SMXII controls. Cost is in the $2600 range plus shipping and installation. If you are handy and don't mind standing on your head, it could be a DYI project.

 

[jg300da]

First off the 12K BTU unit is the factory installed unit on every 320DA, so you can cross off lack of capacity as an issue. In addition a frozen coil evaporator coil is an indication of too much capacity brought on by a reduction of air flow, not too little. You can also cross off a plugged or restricted condenser as a possible suspect, the symptoms of that would be elevated evaporator temps, not freezing. The evaporator coil freezes because the flashing refrigerant cannot absorb enough heat from the air passing over it. Some things to check are dirty coil or filter, closed vents or collapsed or crushed supply ducts, dirty or blocked blower wheel, or a low fan setting that is too low (this is adjustable in the setup menu). Anything that can impede supply air flow.

 

[tawcat]

First off the 12K BTU unit is the factory installed unit on every 320DA, so you can cross off lack of capacity as an issue. In addition a frozen coil evaporator coil is an indication of too much capacity brought on by a reduction of air flow, not too little. You can also cross off a plugged or restricted condenser as a possible suspect, the symptoms of that would be elevated evaporator temps, not freezing. The evaporator coil freezes because the flashing refrigerant cannot absorb enough heat from the air passing over it. Some things to check are dirty coil or filter, closed vents or collapsed or crushed supply ducts, dirty or blocked blower wheel, or a low fan setting that is too low (this is adjustable in the setup menu). Anything that can impede supply air flow.

Blocked blower wheel? Can you explain this?

The blower earlier in the season seemed to making a bit of noise. Louder than usual while running. We adjusted the fan speed, to see if that would help. Hmmm, could the blower be the problem? Although each vent seems to blowing a very good amount of air, so I'm not sure how the blower could be the problem. But then again I'm not an HVAC guy!!!

 

[jg300da]

Check the inlet of the blower wheel to see if something is blocking it. Also check the vanes to see if they have dirt or debris on them. The only noise you should hear from the blower is the sound of moving air.

 

[billnpat]

Stan, thanks for sharing that info.......:thumbsup:

 

[tawcat]

Check the inlet of the blower wheel to see if something is blocking it. Also check the vanes to see if they have dirt or debris on them. The only noise you should hear from the blower is the sound of moving air.

My a/c guy it sounded like maybe a bearing was going. But I'll surely check the vanes to make sure they are clean as well.