Salon temperature

[bmac]

I have 2 zone A/C, one zone for the salon the other for the two staterooms. Both A/C systems are cooled by a common raw water pump. It's been in the mid to upper 90's for an extended period. During this period the stateroom A/C has maintained a relatively constant 68 degrees, day and night. The Salon A/C starts the day fine at 68 degrees but the temperature slowly rises until it stabilizes at about 74 to 76 degrees. It feels as if the unit is blowing plenty of cold air but the Salon is noticably warmer than the system is set at. The filters on both units are clean as is the raw water strainer. I don't think it's water flow as the other unit is fine. Has anyone seen this on their multi unit A/C boat? Any suggestions?

 

[sbw1]

Close the shades on the hatches and windows. You could try setting the offset a little lower in the salon using the set up function in your software so your starting temp is lower than 68.

 

[shinsr]

Brian,
I have noted that if I dont close the "sunroof" shade in my saloon in this weather I have a similar problem. With all of the windows on your boat you may not have much luck other than to keep those shades and curtains drawn as much as possible.

 

[tobnpr]

Q is: Does this represent a change? Or have you not owned the boat long enough to have a history regarding this issue?

If it's "new to you", I agree with the above posts. I always keep the sunbrella covers on the hatches during the summer to reduce the heat gain.

 

[elreyos]

We have temps well over the century mark, and our salon unit will hold the the temp at 65 deg with no problem. The only time I've and a problem is when the filters get dirty. Are you sure you've cleaned all the filters? I know the DA may be a little easier to cool because we dont have all the windows the sedan has. However even the cockpit ac does a good job in these temps the same goes for my Buddies 52DB. Now that I think about it my friend does mention that his salon ac does have to work to get the salon cool if the mains are hot after a run.

 

[fwebster]

Sundancers and Sedan Bridges are different animals.......the bridge boat has a deck house and more glass so they are harder to cool and keep cool than DA's. The other issue is that the interior layout and duct locations may mean that there are some dead air spaces in the salon/galley area. I've never heard a 44DB owner with that complaint, but I have seen it on early 480DB, and early 420DB's.

 

[jpk33]

One other varible is how often are you opening the cabin door? In warm weather that influx of warm (hot) air will tax the AC.

 

[jetlag]

We had an insulated sunbrella cover made for the windshield. Makes all the difference in the world. What you're seeing is what we live with for four months out of the year in Houston....blazing hot sun. And that's exactly how our 44db acted until we replaced the mesh cover with the insulated one. Best $350 you can spend.
Jet Lag
2007 44DB

 

[bmac]

This is our third season with the boat and although it's not a "new" issue it appears worse this year than in prior seasons. The blinds are always drawn during the day and so is the rear curtain. Door opening is fairly frequent and the salon AC is right by the door, but I don't think that's the primary driver of the problem. Jet, where did you get the windshield cover made? Is it Sunbrella or some other material? Is it solid or somewhat translucent?
I'm also wondering if something is up with the unit itself. Wouldlow freon look like this? How about coil internals, could they foul at a different rate than the Stateroom unit even though they see the same hours of raw water flow?

 

[fwebster]

Low freon would make the unit cycle more often, and a quick way to check the efficiency of the unit is to measure the temperature of the plenum air with a digital thermometer before the ducting at the same point on the forward and aft units and compare them.

Yes, the 2 units can and usually do foul at different rates.........has to do with use, the cooing water runs and water temps. Swim around to the a/c outlets and feel the water coming out of both units when the units are running. If you have a fouled line, the water will be noticeably warmer. But keep in mind that water flows out of both outlets when either unit is running. Generally, if you have an A/C discharge line that is fouled enough to cause a meaningful rise in the cabin temps , the decrease in water flow is obvious.

I'm betting that you are dealing with heat gain via the "greenhouse" windows in the cabin vs. none in the stateroom.

 

[Skuza]

What about the calibration of the temp sensor on the control pad? I noticed a similar situation on ours and recalibrated the temp sensor. The two zones seemed to fight with each other over temp settings. It was outlined in the owners manual for the SMX control. I did it with a cheapo outdoor thermometer. I placed it in a central location to the area controlled by the pad I was adjusting and let it stabilize for an hour. Alos make sure its not in the path of any airflow. I then did the recalibration procedure. After doing both zones it seems like the worked together closer. If you do this I would recommend using a better thermometer than the one I used.
I do keep most of the shades closed even though they are small. Perhaps your percieving the temp different due to the amount of sunlight coming in. Kinda like standing in the sun on a cool day. You will feel warmer than you would think at a given temp.

 

[rmadaris]

I am having similar cooling issues....and simply can't gedt to 68 degrees period. I was wondering if it could be the water temp, which is 87 degrees in Charleston, SC. Also, if the lines are fouled (the strainer was pretty nasty) how do you clear them?

 

[Texashornet]

We had an insulated sunbrella cover made for the windshield. Makes all the difference in the world. What you're seeing is what we live with for four months out of the year in Houston....blazing hot sun. And that's exactly how our 44db acted until we replaced the mesh cover with the insulated one. Best $350 you can spend.
Jet Lag
2007 44DB

Hi Jetlag
I'm also in the Houston area and have been thinking about having a cover fabricated for the windshield of my 400db similiar to what you have done. May I ask where you had the cover made?
Steve

 

[Robski97]

Brain,
Im insulted !! The a/c unit is probably just undersized. I have same issue. Bay water temp is up which degrades the units capacity. Measure the supply air temp coming out of the unit . There should be 15 -20 degree difference between the supply temp and the space temp. U need a shade on the those windows too !! will make a huge difference.

Oh and I got ur message from Dom @ montauk( small world )

Rob

 

[tobnpr]

I've seen some bridge boats with white sunbrella all around (not just the windhsield). Anything to cut down the heat gain as has been said above...

 

[acs330]

You could try to back flush your system through the thru hull where each A/C discharges. I did this several times and it was amazing how much gunk came out of the discharge. I used to do this with the A/C pump off but recently was having the same problem and a local mechanic said to do it w/ the pump on. I did, even more crud came out and it solved the problem.
I also wet down the bow and sides when at the dock several times/day when it's hot/sunny and this also seems to help.
I use a piece of hose approx the same diameter as the thru hull fitting and put a brass twist nozzle in the tube and open fully for 5 to 10 seconds, pull the tube out for a while and do it again until the water running out is clear.

 

[bmac]

Brain,
Im insulted !! The a/c unit is probably just undersized. I have same issue. Bay water temp is up which degrades the units capacity. Measure the supply air temp coming out of the unit . There should be 15 -20 degree difference between the supply temp and the space temp. U need a shade on the those windows too !! will make a huge difference.

Oh and I got ur message from Dom @ montauk( small world )

Rob

Rob, don't feel insulted it's my dementia setting in (I turned 50 last weekend and forgot you are the reefer man) When I return from this trip I'll get a calibrated thermometer from work and check the air supply vs. space difference (as Frank also suggested). I have a feeling extra high temps are the culprit as I've also found a pretty wide (4-8"x 4') in the bulkhead seperating the salon where the A/C uint is and the exterior cabinet in the cockpit, essentially allowing outside air to get to the A/C inlet constantly. Although that can't be a change in the way the boat has been since new it can't be helping. I'm wondering if this combined with 3 seasons of built up fouling on the raw water side of the unit have conspired to give me this problem. Any thoughts on whether a chemical cleaning would help this issue if all else were the same?

 

[bmac]

Low freon would make the unit cycle more often, and a quick way to check the efficiency of the unit is to measure the temperature of the plenum air with a digital thermometer before the ducting at the same point on the forward and aft units and compare them.

Yes, the 2 units can and usually do foul at different rates.........has to do with use, the cooing water runs and water temps. Swim around to the a/c outlets and feel the water coming out of both units when the units are running. If you have a fouled line, the water will be noticeably warmer. But keep in mind that water flows out of both outlets when either unit is running. Generally, if you have an A/C discharge line that is fouled enough to cause a meaningful rise in the cabin temps , the decrease in water flow is obvious.

I'm betting that you are dealing with heat gain via the "greenhouse" windows in the cabin vs. none in the stateroom.

Frank, I agree with your point on the solar gain difference between the salon and the staterooms. However, the salon A/C unit running continuously and not maintaining temps is a change that occured this season. Waterflow out of the salon unit appears stronger than the forward unit but I've always attributed that to the much longer run forward (and it's been that way since new). I'm in the second week of a 2 week trip and will check air discharge temps with a calibrated thermometer when I return to try to get to the bottom of this. I'd rather fix the problem (if there is one) than mask it by just reducing the solar gain with a windshield cover like Jetlag has, though I may go that route as well to reduce the overall load on the system.

 

[Robski97]

Brain,
NO chemicals.. Ill come by one weekend and flush it for u. But thats not ur issue.

Its undersized equipment and too large load . Also unconditioned air migrating into the space doesnt help....

Alittle insulation during construction would help but that's another thread completely!

Rob

 

[Converse48]

Brian-
This is a common issue with 44DBs. I battled with Sea Ray when my boat was new. Local A/C tech told me that the flow from the salon A/C was too small. Sea Ray's answer was that CruisAir signed off on the design. Here's what I have done the following things to address, and for the most part rectify, the issue:

1- I have had 90% sun shades made for the side windows and a 100% (blue sunbrella) for the front window that I use when temperatures are forecast to be 95 or above (which has been all too frequent this year).

2- The outflow of the salon unit was quite restricted from the factory. The opening of the vent at the bottom of the register in the salon was considerably smaller than it should be... see this picture here:

Note how the opening on the underside of the register is significantly smaller than the 7" oval opening that it is attached to. By my measures this represented a 40% reduction in the cross-section. Something tells me CruisAir did not sign off on that! I widened the opening on the underside of the register to be the same size as the actual duct attached to it. This greatly improved airflow to the main salon register.

3- I added a duct from the salon A/C unit to the galley. You can see it on the right here:

(Pardon the fingerprints on the door).
This has also improved overall airflow across the salon unit and has eliminated "dead space" (as Frank mentioned) in the galley. I added a 7x7x4 tee to the outlet of the A/C and ran 4" duct behind the love seat to the false panel (which is no longer false) in the galley. There was some non-structural modification involved behind the galley cabinets... but that's another whole story. Let's just say that the guys in the yard over the winter were wondering what the hell I was doing with a Sawzall with a 10" blade on it...

4- I had new custom supply registers made for the forward A/C outlets to have dampers, so I can selectively force more air to the outlet from the front unit that is in the salon (up next to the dinette). And I put an oscillating fan up there to make sure that sure finds its way around the salon.

5- I also had a 90% white sun shade made up that we put up in place of the three middle aft curtains to keep the sun from shining directly in to the salon.

6- I insulated the cockpit locker just to the right of the salon door. The openings in the locker all provide hot, humid, unconditioned air directly to that unit.

None of these were particularly cheap or easy fixes though, so you should exhaust all other options before pursuing.

Can I get the little blue wrenches next to my name now?