To run the A/C or not..

[stormchaser]

Most Hatts have Cruisair and they will keep trying to restart.

I guess that depends on the controls. Mine do NOT restart until I power off and back on. But I also have brand new digital SMXht controls and cards.

 

[Pascal]

well, both of these sounds like poor engineering to me... for one, the tubes must be too small. On the 70 footer i run, there are two fiberglass tubes that run the length of the boat, there might be PVC inside..., but it's at least 2 1/2" and they were smart enough to route all the Air con water in separate thru hulls.

on the older hatteras, i guess that if you were to plug the discharge at the bottom of the sea chests water could rise and back flow into the bilge thru the bilge pump discharges... possible, but i guess it's one of those what ifs that never happened. if it did, hopefully at least one bilge pump woudl be on a another sea chest...

let's put it this way... down south, tens of thousands of boats have their AC running 24/7 and almost 365... accidents are VERY rare, in fact i've never heard of one unless negligence was involved.

as to wear and tear, i strongly believe that unused system are more prone to failure... for instance if during winter i dont' run my AC for a few weeks, the pump has problems starting up...

 

[stormchaser]

I agree, lack of use is BAD. I always use my ac at least once a month, even in winter...even if for just a min or two. I also flip it over to reverse cycle heat once a month in summer...just for a min or two...just to exercise it.

 

[Trojan]

I never leave mine run more than 24 hours unattended. After all mine are only 30 years old. And you guys are worried about using and leaving shore water unattended. not a whole lot of difference. All AC cooling is below the water line since the pumps are not self priming. The insurance companies state that most sinking happen at the dock. I never leave the water or AC running unattended longer than 24 hours or over night. My 43 cools quite fast. Faster if I spray the outside of the Solon with cold hose water. I have a solar fan that works quite well and I leave the bow protected port holes open when I leave for any great time.

BILL

 

[Traveler 45C]

on the older hatteras, i guess that if you were to plug the discharge at the bottom of the sea chests water could rise and back flow into the bilge thru the bilge pump discharges... possible, but i guess it's one of those what ifs that never happened.

No, it happened exactly like that to me. The seachest filled up with growth restricting the flow and water back fed through the bilge hoses back into the boat. The solution to this problem is dedicated thru hulls for the A/C.

I leave mine running set at 80f, but I check on the boat often.

 

[saltshaker]

I'm with Dave on this. I've never had a problem but it just seems too risky to have a raw water pump running for days when I'm not there. The fact that he sees problems with customers boats makes me feel I am making the right choice.

I also have a 46C with new compressors and SMX controls. I do use the dehumidify function which turns each unit on for a predetermined time. I have mine set to run 1/2 hr each every eight hours. I stagger when the units run so only 1 runs at a time. I would never leave the units on when I had the old rotary controls. If you don't have digital controls, I would highly recommend you upgrade. I put off doing mine for a long time. Last summer one of my original 1974 Cruisair units died so I decided to change out all the controls when I had the new unit installed. Amazing how much better they work.

My 46C cools off pretty fast even on very hot days. The salon will cool off in about 20 mins and the staterooms might take about 1/2 hour. We always leave the boat with the blinds closed to keep the heat down.

 

[Angela]

Most Hatts have Cruisair and they will keep trying to restart.

I don’t have digital controls. I do have the original CruisAir system. Everything is original with the exception that the condensing unit on the modulating system that serves the staterooms has been replaced, but not the evaporators to that system. If water is cut off, each of my condensing units will shut down and will not continue to try to start. They each have their own individual overheat breaker located in a control box on the wall. It came from Hatteras this way and it works. No water..no workie.

 

[REBrueckner]

"I do use the dehumidify function which turns each unit on for a predetermined time."

nice feature, but I wonder why they don't provide a humisdat control like portable dehumidifier units so you can pick your level of relative humidity... doesn't seem like it would be expensive nor difficult....

 

[34Hatt]

I too have the SMX and agree they are better and some what safer mainly for the fact of doing like Jack said and use the dehumidifying mode.

But the problem is you only have a 50/50 chance of the over heat shut down to work! If the output side of the ac springs a leak the unit will work just fine all day and night.

What I do is make sure my bilge pumps can out do the ac pump!

 

[Pascal]

"All AC cooling is below the water line since the pumps are not self priming"

not really... the strainer, line to the pump, pump and a little bit of the outlet line are under WL but everything else is above.

so, to be really safe you should close the sea cock before leaving the boat since a failure below the waterline will have the same results whether or not the pump and air cons unit are working.

then you shoudl also close the sea cocks to these old galley maid heads...

and to the generator...

and...

indeed, most sinking take place at the dock, but most of them involve small boats, not air con systems.

I bet that most boats are lost from boat fires due to heaters than from sinking because of air cons.

 

[Angela]

If I closed all of my seacocks (I think there are 14 of them)when leaving the boat each time, I'd never get off the boat, or I'd have arms that looked like those of a body builder! Instead, I have insurance if some catastrophe happens when I'm on the boat or away. I do inspect my stuff and maintain/replace it on a regular basis and can say that I'm not scared of it. I can sleep at night, and I don't worry about the boat when I'm gone for a few hours or a day.

I'm more concerned about fire which is something I can't really "see" that's going to happen. I can see a hose or fitting going bad and fix it, and a lot of boats can recover from flooding or sinking...just ask Yachtsmanwille, but there's not much I can do with a blob of melted plastic.

 

[fissioneng]

I had a pinhole leak develop in the water hose between the pump and one of my condensing units in a very awkward spot. It sprayed seawater all over the the PWX box that controlled the unit causing a nice 240 volt spark and unit shutdown. There was no flooding because the pinhole leak was above the waterline thankfully. The spark actually charred the terminal block causing it to be permanently conductive. I had to replace the terminal block and hoses. Fortunately I was in the engine room when this all happened. I have since removed this PWX from the system.

Two weeks ago, I had one of my Honeywell thermostats fail and it started oscillating the pump and the condensing unit (start/stop/start/stop in rapid succession). It wouldn't stop until I shut the unit off.

So, obviously stuff can happen. I think the answer here is it depends on the health of your system. If you have replaced a lot and run your system a lot, it is probably okay to leave it running. If your system is older, and it has some less than healthy components, I wouldn't leave it running for days unattended unless I knew someone was regularly watching it.

 

[captddis]

I guess that depends on the controls. Mine do NOT restart until I power off and back on. But I also have brand new digital SMXht controls and cards.

I did say that they will restart if you do NOT have digital controls. The SMX have the failsafes that is why Crusair doubles the warranty if you have SMX's.

 

[stormchaser]

OK, sorry. Oh, the SMX is great, well worth the cost to upgrade...

 

[captddis]

well, both of these sounds like poor engineering to me... for one, the tubes must be too small. On the 70 footer i run, there are two fiberglass tubes that run the length of the boat, there might be PVC inside..., but it's at least 2 1/2" and they were smart enough to route all the Air con water in separate thru hulls.

on the older hatteras, i guess that if you were to plug the discharge at the bottom of the sea chests water could rise and back flow into the bilge thru the bilge pump discharges... possible, but i guess it's one of those what ifs that never happened. if it did, hopefully at least one bilge pump woudl be on a another sea chest...

let's put it this way... down south, tens of thousands of boats have their AC running 24/7 and almost 365... accidents are VERY rare, in fact i've never heard of one unless negligence was involved.

as to wear and tear, i strongly believe that unused system are more prone to failure... for instance if during winter i dont' run my AC for a few weeks, the pump has problems starting up...

I guess if you don't hear about it it does not happen! I had three boats spring a leak in their manifold last year, one sprayed the engine room, one sprayed the pump and ruined it and one just dribbled. The last two were 2007 model boats. I have done Marine AC work since 1984, but it is always good to hearfrom an expert like you.

 

[Top Shelf]

When I'm in town and can check on the boat every couple days I do run the AC all the time. In So FL it's just too hot. But I will tell you a year or so ago I got a pinhole in the 1 to 3 manifold and it sprayed raw water right into the old Sentry 230 volt AC battery charger. Salted up the front of the Stb main and eventually shorted out the March pump. it must have done that for hours. Why that didn't start a fire is beyond me, the Lords blessing and good luck.

The boat is in San Sal now and the AC's are shut down along with the Through hulls. But it will routinely get over 100 degrees in there and I know the fridge and freezer are suffering. Good idea about leaving the ports in the showers open. If that cools it just a few degrees that would help. Thx.

 

[Pascal]

I guess if you don't hear about it it does not happen! I had three boats spring a leak in their manifold last year, one sprayed the engine room, one sprayed the pump and ruined it and one just dribbled. The last two were 2007 model boats. I have done Marine AC work since 1984, but it is always good to hearfrom an expert like you.

did these boats sink? obviously leaks can happen... following your logic, i guess we shoudn't run air cons at night either... you never know, while you're asleep your air con pump could start leaking so let's shut them down at night...

what kind of material were these manifold made of?

 

[captddis]

did these boats sink? obviously leaks can happen... following your logic, i guess we shoudn't run air cons at night either... you never know, while you're asleep your air con pump could start leaking so let's shut them down at night...

what kind of material were these manifold made of?

I did not know you used air, I thought you anchored out and opened the windows. Hey maybe your AC sprung a leak and ruined your engine.



BTW manifolds were Cruisair brand Cupro nickel. In all cases it was the T fitting that let go.

 

[Angela]

I did say that they will restart if you do NOT have digital controls. The SMX have the failsafes that is why Crusair doubles the warranty if you have SMX's.

Not true in every situation. I've got the old rotary dials and Honeywell thermostats...nothing digital at all, and OEM overheat "breakers" from 1980. When water stops flowing, the system shuts down and will not restart until the breaker is pushed back over by my finger. I have a "breaker" on each of my three control/connection box (one for each condensing units) in the engine room that trips with an overheat/lack of water flow. These "breakers" are in addition to the double pole electrical breakers on the electrical panel. Hatteras built my boat this way. While some systems may try to restart in the absence of digital controls, it's not fair to say that all of them will.

 

[captddis]

Not true in every situation. I've got the old rotary dials and Honeywell thermostats...nothing digital at all, and OEM overheat "breakers" from 1980. When water stops flowing, the system shuts down and will not restart until the breaker is pushed back over by my finger. I have a "breaker" on each of my three control/connection box (one for each condensing units) in the engine room that trips with an overheat/lack of water flow. These "breakers" are in addition to the double pole electrical breakers on the electrical panel. Hatteras built my boat this way. While some systems may try to restart in the absence of digital controls, it's not fair to say that all of them will.

I think you already posted this. Check # 27. I will put a disclaimer in just for you.

The question was asked whether to run or not. I gave my reasons and observations. Feel free to do whatever you want.