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A/C Efficiency
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Author:  firecadet613 [ Thu Jul 22, 2010 6:14 pm ]
Post subject:  A/C Efficiency
Some of you may know I have an ongoing AC issue. In Chicago when I met up with a few other boats, the 268's had no problem keeping their cabins at 68 degrees. Once the sun comes out...mine heats up and cannot keep it below 79.

As of right now, I have the problem narrowed to under capacity. I've added a vent forward of the galley, flushed the lines, and just now today tore apart the aft cabin so I can check pressures. They are all fine.

The other two boats in Chicago just had the coloring near the rub rail....mine is the classic color band with dark blue. I wouldn't think thats enough, but apparantly it is.

Shanman14's 278 had his A/C upsized under warranty from a 5K BTU unit to an 8K unit.

It's 90 out...and I'm getting an output of 63 on high, and 50 on low fan speed. What are you seeing, and ambient air temps?

So far after my talks with Cruisair...it appears my unit is functioning properly.
Author:  Flyer51 [ Thu Jul 22, 2010 7:37 pm ]
Post subject:  Re: A/C Efficiency
I meant to call you with my experience from last weekend. It was sweltering here when we got to the lake on Saturday. I unloaded the boat then went out and started the gen and AC. We pretty much went straight to the slip to unload from our trip the prior weekend and kept the AC running full on. I got unloaded and we headed out on the lake with the gen and AC running. I did notice that during the afternoon our boat really didn't cool all that well. As you know I rarely run the generator while out to keep the AC on but it was just too hot. The boat did cool down later in the evening but we were under cover in the slip which I think makes a big difference. I think you're just absorbing a lot of sun and with water temps in the Midwest closing in on 90 your AC/heat pump unit is just not able to keep up.

Sounds like you may need to upgrade to a larger unit. I'll be the 318 cools quite nicely :lol:
Author:  firecadet613 [ Thu Jul 22, 2010 8:40 pm ]
Post subject:  Re: A/C Efficiency
Thanks Dennis. I was about to shoot an email your way. I've been chatting with Ben about it today. He doesn't use the auto fan speed, but keeps it on 1 or 2...says it cools better. By the time I decided to try that, the sun was going down, so not the same comparision.

I'll give it a shot this weekend and see how it goes. I'm still in shock that waking up that morning at 11:30 and it saying it was 79 in my boat :o
Author:  Cap'n Morgan [ Fri Jul 23, 2010 6:16 am ]
Post subject:  Re: A/C Efficiency
The fan speed set to 1 or 2 will not cool it any better than auto, if it is not cooling properly to begin with. The only time we have ever had an issue with our AC not cooling properly, is when it was 90 degrees outside, and we set the temp to 69 degrees. The unit froze up in a short time, and did not get very cool. It's more than the system was designed for to get the temp that low with ambient temperature so high, and desired temp so low.
We have learned to set it at about 73 to 75 degrees when it is hot outside, and we have had no problems with freezing up since then. Who needs it to be 69 degrees when it is 90 outside? 75 degrees feels like a meat cooler when it is that hot and humid outside of the cabin.

When in the slip, our boat is exposed to direct sunlight for 16 hours a day, and the 6,000 BTU unit keeps it nice and cool in the cabin all day long.

And finally, a 5,000 BTU unit is more than enough to keep a small cabin cool. Hell, the cabin is half the size of a small camping trailer, not too difficult to deal with really. We have a 5,000 BTU window airconditioner in our house, and that keeps the entire 1st level at 72 degrees without any difficulty when it is hot outside. If you have a kid running in and out of the cabin a dozen times per hour, people getting snacks and beverages from the cabin every 15 minutes, and the cabin door is opened often while this is occuring, you WILL have problems keeping the cabin cool. Portlites must remain shut, and the cabin door must be opened and closed immediately after each use, if not, it will never keep temperature.
Author:  firecadet613 [ Fri Jul 23, 2010 7:36 am ]
Post subject:  Re: A/C Efficiency
Do they make a shade for the bow hatch? Similar to what they have on the newer biggger boats or just a snap in one?
Author:  Wet Doggg [ Fri Jul 23, 2010 11:59 am ]
Post subject:  Re: A/C Efficiency
First off...have a canvas cover made for your hatch. We had one made for our cruiser and it helped a ton. Second...you have to limit how much you open the cabin door to go in and out. Think about how small your cabin is and how much air is replaced just by opening the cabin door once...probably close to 25% - 40% I bet. So...get a cover or use a towel...keep the cabin door closed and set the temp at a realistic temp.

Heck...my Dad's Carver 506 have two large AC units...if it is hot outside there is zero chance he can cool the cabin to 68 degrees. Need to realize it is not your home AC system.
Author:  firecadet613 [ Fri Jul 23, 2010 1:46 pm ]
Post subject:  Re: A/C Efficiency
Good points. Thanks Wet Doggg. How did you secure the canvas cover? Inside or out? Any pics?

In the 90s here this weekend. Should be fun!
Author:  Cap'n Morgan [ Fri Jul 23, 2010 2:36 pm ]
Post subject:  Re: A/C Efficiency
You know what a PIA that screen on the 268 is to put up. The way the hatch is, I don't think
you can get a canvas cover for it and have it shut tight. We never could. Was not able to find a sliding
shade/screen for the hatch on our 268 either. Maybe it's different on a 2004 model.
Author:  firecadet613 [ Fri Jul 23, 2010 2:42 pm ]
Post subject:  Re: A/C Efficiency
Well the admiral's are talking. My wife had an answer for the shade idea. The split shade/screen similar to whats on the 318/338. Should bolt right up. Hey....now these boat dollars aren't being spent by me!
Author:  firecadet613 [ Fri Jul 23, 2010 3:50 pm ]
Post subject:  Re: A/C Efficiency
Capn you edited it out!

What did you use to make it blacked out? I just priced the shade screen....same one on a 318 nonetheless that will fit my boat. $260 from Bomar direct, $227 via Defender.

A bit rich for my blood..unless blacking it out will work. We will give it a shot this weekend. What would material would work to black it out the best?

Image

You remove the white interior trim ring, and install this in its place. It is VERY slick!
Author:  SundayDinner [ Sat Jul 24, 2010 1:18 am ]
Post subject:  Re: A/C Efficiency
I don't think shade on the hatch or the classic color band is your issue. Although I do think shading the hatch will help. As you know, we have the classic color band in all black on our 258. While I'm sure it doesn't help keep the boat cool, we have been getting it down to 70 or so in the late afternoon sun. It gets downright frigid once the sun dips. Not an A/C expert, but sounds like a coolant/performance issue to me. The vent addition was very nice! May do that to ours. But does no good if you're just pumping around more hot air. It's one thing gor it to struggle during daylight hours, but you should definitely get below 75 degrees overnight.
Author:  acguy [ Sat Jul 24, 2010 6:03 am ]
Post subject:  Re: A/C Efficiency
Have you ever had a service tech ever put a set of refrigerant gauges on the system to check the operating pressures. Sounds like the system may be slightly short on refrigerant. If the system is slightly short on refrigerant it will run and never make set point. Also check to see what the temperature difference is between the discharge air coming out of the unit compared to return air going through the evaporater. Not sure of the design specs of the unit but I would think that design would be around a 15 degree temperature difference. Start with the TD across the unit and then if your not getting at least 15-20 then find someone who can put a set of gauges on it. You would be surprised at the amount of units that come shipped short on refrigerant from the factory!
Author:  firecadet613 [ Sat Jul 24, 2010 6:19 am ]
Post subject:  Re: A/C Efficiency
I thought I had put that info in this post.

Anyways...pressures are great. Thursday I put a set of gauges on it. 68 low pressure high of 200....high is a bit low, but the low right in the middle of the spec per Cruisair. I had to add a bit of R22 to get it there but not much. Boat air temp of 85, its pushing out 62 degree air on the high fan setting, 54 on slow.

It appears to be working fine. I don't recall it every freezing up...but will keep an eye on it this weekend.

Nighttime 68-70 is no problem, only when the sun is out. And that sounds like the way it is. A friends SR 340 wouldn't get below 75 yesterday.....but its VERY hot and humid out.
Author:  acguy [ Sat Jul 24, 2010 8:13 am ]
Post subject:  Re: A/C Efficiency
firecadet613 wrote:
I thought I had put that info in this post.

Anyways...pressures are great. Thursday I put a set of gauges on it. 68 low pressure high of 200....high is a bit low, but the low right in the middle of the spec per Cruisair. I had to add a bit of R22 to get it there but not much. Boat air temp of 85, its pushing out 62 degree air on the high fan setting, 54 on slow.



200 psi on the high side is perfect that is just over 100 F condensing temperature. Looks like it runs just fine. I'm looking at putting A/C in my 248 but not sure what size to put in. If your unit is sized to small it won't cool the space... If it's too big you will get the temp down but won't to a very good job of removing the humidity!
Author:  firecadet613 [ Sat Jul 24, 2010 8:53 am ]
Post subject:  Re: A/C Efficiency
Good to hear. I picked up my brothers gauges and R22....I'm used to car or home A/C. I know one 278 had its unit replaced....they put in a 7k unit vs a 5k that it came with only because they could get it quicker. Same size constraints also. Cruisair signed off on a 5k unit when the 268 wqas designed. As you can tell, I've done my research on this issue. 5k should be good for your 248.

Ill post back with how this weekend goes.
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