Leaving Air Conditioner running on when not at boat

[patswil]

Originally Posted by Panacea2183

Guess you don’t live in Florida.
Ever try to get mold out of your boat after no A/C?
Yes we live in a world where we are addicted to many things.
I for one run my A/C 24/7 at my dock. Pristine interior no mold or foul smells.
Would you not run the A/C in your house? When your gone?
Turn up the temp still removes humidity.
Safe travels and stay well!

I leave the Mariaire on for days at a time. if you AC is plumbed for overboard discharge of the condensate, then what's the reason for a fuss....even automatic bilge should cover things. I wouldn't leave the shore water from the dock on....could sink the boat. Only takes one broken hose fitting to ruin your day

[smj]

Originally Posted by patswil

I leave the Mariaire on for days at a time. if you AC is plumbed for overboard discharge of the condensate, then what's the reason for a fuss....even automatic bilge should cover things. I wouldn't leave the shore water from the dock on....could sink the boat. Only takes one broken hose fitting to ruin your day

Only takes one broken hose fitting from your Ac to ruin your day. Lots of people here have tons of faith in their bilge pumps.

[Palarran]

Originally Posted by patswil

I leave the Mariaire on for days at a time. if you AC is plumbed for overboard discharge of the condensate, then what's the reason for a fuss....even automatic bilge should cover things. I wouldn't leave the shore water from the dock on....could sink the boat. Only takes one broken hose fitting to ruin your day

Originally Posted by smj

Only takes one broken hose fitting from your Ac to ruin your day. Lots of people here have tons of faith in their bilge pumps.

Lets see, so first you would have to have the 1 in 100,000 boat that has a hose break and flood the boat, then have the unfortunate 1 in 100 bilge pump not work. What are the odds?

If someone doesn't want to run their A/C for environmental or more likely financial position, well, ok. But it still seems silly to worry about a hose breaking and flooding a boat while your not on it given the full spectrum of things that actually flood boats, or make masts fall down, or rudders break, or the multitude of real problems that sink boats.

I have to believe most of you have pulled apart tubing from fittings after removing the hose clamps. Was it easy? Did you have to use a screwdriver to help loosen it? I'm not sure the minimal pressure from a A/C pump is enough to break loose a fitting even if it never had a hose clamp on it, let alone having two of them. Any hose does degrade and go bad, but that's a loss due to utter lack of observation and maintenance. Someone who keeps their boat in such a condition is more likely going to loose it due to a broken anchor shackle.

As an FYI, there is no energy savings from using a dehumidifier to remove moisture compared to an air conditioner. In fact, it might be less efficient. Both the evaporator and condenser are using the same ambient air with a dehumidifier (air cooled). For an air conditioner with a dehumidification mode it lowers the blower speed in order to increase the delta T across the evaporator. That allows more condensation and quicker. Water cooled vs air cooled - no comparison in efficiency. I don't know the specifics of each marine A/C dehumidifier but mine is run by setting a specific humidity level, not by an amount of time per hour or day. Super efficient BTW especially coupled with my solar array.

[Group9]

Originally Posted by smj

The best maintenance for thru hulls is to have none. Impossible on some boats I know.

Our last boat had 13 thru hulls but they were easy to get to. I slept good at home knowing that they were all closed, with a dehumidifier that drained into the bilge to keep mold and mildew at bay. (I knew it couldn’t dump enough water in there in a year to sink it if a bilge pump failed.

We do the same on our current boat, (17 thru hulls) although I admit now I often leave some thru hulls open because they are so much harder to get to (and, I don’t sleep, as well.)

[smj]

Originally Posted by Palarran

Lets see, so first you would have to have the 1 in 100,000 boat that has a hose break and flood the boat, then have the unfortunate 1 in 100 bilge pump not work. What are the odds?



If someone doesn't want to run their A/C for environmental or more likely financial position, well, ok. But it still seems silly to worry about a hose breaking and flooding a boat while your not on it given the full spectrum of things that actually flood boats, or make masts fall down, or rudders break, or the multitude of real problems that sink boats.



I have to believe most of you have pulled apart tubing from fittings after removing the hose clamps. Was it easy? Did you have to use a screwdriver to help loosen it? I'm not sure the minimal pressure from a A/C pump is enough to break loose a fitting even if it never had a hose clamp on it, let alone having two of them. Any hose does degrade and go bad, but that's a loss due to utter lack of observation and maintenance. Someone who keeps their boat in such a condition is more likely going to loose it due to a broken anchor shackle.



As an FYI, there is no energy savings from using a dehumidifier to remove moisture compared to an air conditioner. In fact, it might be less efficient. Both the evaporator and condenser are using the same ambient air with a dehumidifier (air cooled). For an air conditioner with a dehumidification mode it lowers the blower speed in order to increase the delta T across the evaporator. That allows more condensation and quicker. Water cooled vs air cooled - no comparison in efficiency. I don't know the specifics of each marine A/C dehumidifier but mine is run by setting a specific humidity level, not by an amount of time per hour or day. Super efficient BTW especially coupled with my solar array.

As I stated earlier, I’ve seen more than a few boats go down from problems related to either leaving the ac running or leaving the pressure water on while absent from the boat.
I personally don’t take that chance, instead I will use a product like SunPac which does a great job of keeping mildew at bay without any chances of sinking my boat or burning the end of my shore power cord.
Maybe I’m stupid for being cautious?

[jtsailjt]

Originally Posted by smj

Only takes one broken hose fitting from your Ac to ruin your day. Lots of people here have tons of faith in their bilge pumps.

Unless the broken hose fitting is downstream of the AC unit, the pump will shut off when the AC unit is starved of cooling water, over-temps, and shuts off. So it’s pretty unlikely that water will actually be pumped into your boat at a high rate. So, in the very unlikely event of a hose fitting breaking while the boat is stationary with nobody aboard, which will most likely result in seepage through a crack in the fitting rather than an entirely broken off fitting, don’t you think it’s pretty likely that the bilge pumps should be able to easily keep up with this sort of flow, especially since the boat will be plugged into AC power so the battery charger will be on and the bilge pumps can run indefinitely? Yes, any bilge pump or float switch can fail but that’s why I have 3 electric (and 2 manual) pumps on 2 separate circuits with 2 float switches. So, realistically what are the odds of all your float switches or bilge pumps failing at the same time that a hose fitting just decides to fail on a stationary boat with nobody aboard? I suppose it ‘could’ happen but if Murphy is THAT determined to get you, you should also probably seek shelter from inbound asteroids! I can think of about a thousand other circumstances that are more likely to sink your boat and if we worried as much about all of them as some seem to worry about this extremely unlikely scenario, none of us would dare to own a boat.

[smj]

Originally Posted by jtsailjt

Unless the broken hose fitting is downstream of the AC unit, the pump will shut off when the AC unit is starved of cooling water, over-temps, and shuts off. So it’s pretty unlikely that water will actually be pumped into your boat at a high rate. So, in the very unlikely event of a hose fitting breaking while the boat is stationary with nobody aboard, which will most likely result in seepage through a crack in the fitting rather than an entirely broken off fitting, don’t you think it’s pretty likely that the bilge pumps should be able to easily keep up with this sort of flow, especially since the boat will be plugged into AC power so the battery charger will be on and the bilge pumps can run indefinitely? Yes, any bilge pump or float switch can fail but that’s why I have 3 electric (and 2 manual) pumps on 2 separate circuits with 2 float switches. So, realistically what are the odds of all your float switches or bilge pumps failing at the same time that a hose fitting just decides to fail on a stationary boat with nobody aboard? I suppose it ‘could’ happen but if Murphy is THAT determined to get you, you should also probably seek shelter from inbound asteroids! I can think of about a thousand other circumstances that are more likely to sink your boat and if we worried as much about all of them as some seem to worry about this extremely unlikely scenario, none of us would dare to own a boat.

Then I suggest you leave your boat with the ac running.

[jtsailjt]

Originally Posted by Kiwicrew

I cannot see the point of leaving the AC on. Use a dehumidifier with a timer, in the galley sink, to keep the boat dry.

Don’t dehumidifiers and AC units do pretty much the same thing? I can understand using a dehumidifier if the boat wasn’t already equipped with AC, but it seems like unnecessary expense and complication to buy and bring a dehumidifier aboard while your AC unit sits idle. Also, I don’t understand why you’d want to drain water via the galley sink drain because that means locating the dehumidifier above the galley sink, very high in the boat, but the problem area where mold will begin to occur is down near the sole, so that’s the best place to be directing the dry air. At the very slow rate that dehumidifiers or AC units generate condensate, any bilge pump can easily keep up with the flow.

[jtsailjt]

Originally Posted by smj

As I stated earlier, I’ve seen more than a few boats go down from problems related to either leaving the ac running or leaving the pressure water on while absent from the boat.
I personally don’t take that chance, instead I will use a product like SunPac which does a great job of keeping mildew at bay without any chances of sinking my boat or burning the end of my shore power cord.
Maybe I’m stupid for being cautious?

Being cautious is always good but I wouldn’t group the danger from leaving the air conditioning on up there with leaving your boat connected to pressure water. With the latter, your water system is being constantly subjected to a higher pressure than your internal pump generates and is connected to a virtually unlimited source of this high pressure water pushing against every fitting 24/7/365. I could see myself having nightmares about that too! But, for the reasons I explained in a previous post, the likelihood of a leak in the cooling circuit of your AC unit sinking your boat is very remote. 2 entirely different animals.

I think the SunPac option is what I’d try first too if I had to be away from my boat in a warm, moist climate, not because I’d fear that my AC could sink my boat, but because its more reliable. An AC unit can be shut down by an electrical surge or a bearing failure or a tripped CB or a neighbor accidentally disconnecting the cord to your boat or even a leaf or clump of seaweed blocking your cooling water intake. Having your AC unit shut down for one of the above reasons won’t sink you but if not promptly noticed and rectified they will leave your boat with no protection from mold and mildew.

[Creedence]

Here again, the clues reside in the OEM manuals. Crack open a manual from your boat manufacturer (if your boat has one) and you’ll find several advisories against leaving the dock water connected to your boat when it’s unattended. So... follow the manual.

The air conditioner OEM manuals will provide their guidance, and your best bet is to simply operate as they direct. In the case of my particular Dometic unit, there is a dehumidify setting that is recommended for the unattended boat. I don’t think you get any points deducted for operating more conservatively than the manual outlines.


I would be surprised if Dometic made a sustained practice of recommending things that are inherently unsafe in the manuals that they have been producing for decades. The fact that this conversation is even running as long as it is shows there isn’t a firm consensus be way or the other carries implications worth thinking about.

[mack2465]

I'm in Louisiana my ac runs on dehumidify all the time. Usually I am away from the boat 4 to 6 weeks at a time. Had the thru hulls replaced new hoses switched safety valve on the pump hose. 4 stages of bilge pumps. If it sinks it was ment to. As for the environment you all need to come up with a lot better argument than you've put forward so far a well set up ac is not a environmental hazard

[Group9]

We have decided to go a completely different way as an experiment. One of the boats in a nearby slip got two mini-splits for his boat a year ago. We have been letting him be the test bed for us. So far, he loves his and we have decided that we are tired of having the Marine HVAC repairman on speed dial.

So, we'll report back in a few months with our own product evaluation report. One benefit, I know already, will be being able to leave them on without worrying about a hose pulling loose or splitting and sinking the boat.

[skipperpete]

Originally Posted by seandepagnier

since 2 wrongs doesn't make a right, your argument is invalid.

And it gets worse.... in the past, 2 boat owners on the Rlyc marina in Langkawi noticed no charge or metering on fresh water outlets so they hooked the aircon cooling to fresh with a constant overboard flow, 24 hours a day 7 days a week.

[jtsailjt]

Originally Posted by skipperpete

And it gets worse.... in the past, 2 boat owners on the Rlyc marina in Langkawi noticed no charge or metering on fresh water outlets so they hooked the aircon cooling to fresh with a constant overboard flow, 24 hours a day 7 days a week.

I understand why that sounds pretty bad and would be a very wasteful thing to do in most places where we live. But for a place like Langkawi, with about 90” (more than twice the amount Seattle gets) of fresh water falling from the sky every year and making its way into the ground or down rivers and into the sea, and especially during the summer rainy season when AC use is most likely to be most needed, it just might make sense to save the electricity it takes to run a pump and the wear on it and instead use the water from the tap. The reason theres no metering of water there is probably because water is so plentiful that it has no $$ value and any water that falls anywhere near the coast will soon be in the ground or the ocean anyway.

[jtsailjt]

Originally Posted by skipperpete

And it gets worse.... in the past, 2 boat owners on the Rlyc marina in Langkawi noticed no charge or metering on fresh water outlets so they hooked the aircon cooling to fresh with a constant overboard flow, 24 hours a day 7 days a week.

Almost anywhere this would be a horribly wasteful practice but since Langkawi gets about 90” (more than twice what Seattle gets) of rain each year with most of it during the summer rainy season when AC is most needed, it makes sense. Water isn’t metered there because so much fresh water is falling from the sky that they don’t know what to do with it all.