A/C strainer question

[z28jimi]

I leave my boat closed up during the week, and I'm too chicken to leave the A/C on. I've been told that bromine tablets in a turned-off system are not good. I've also been told that putting a couple strips of copper sheet in the strainer IS good, in that it will help prevent growth of crud in the strainer. Any comments one way or the other?

 

[jim rosenthal]

Copper won't hurt anything, at least. We had a thread on bromine tablets- I think the concensus was that it might rot the rubber hoses, but I can't recall exactly. Is crud building up in the system? I have not (yet) had this problem.

I would not leave it running while you are away. No, indeed.

 

[REBrueckner]

I see you are in Flordia and with the heat and humidity there an argument can be made for combatting mold/mildew inside a closed up boat and comfort upon arrival. People leave air conditioners running in homes all the time and of course many people run water cooled air conditioners aboard unattended boats all summer.

The thing that has always prevented me from running air conditioners when I'm not aboard is the risk of blockage to the raw water intake water, such as seaweed or a plastic bag, as well as the possibility of electrical based fires when no one is in attendance. I'm too chicken too.

On the other hand, if debris in the water is unlikely where you operate, I could see checking the electrical components regularly while the a/c is left running unattended. For example, using an IR thermometer to check dockside and boat connections of the shorepower cord for normal operating temperatures and also the fuses or circuit breakers for the a/c compressors. A check, let's say once a month, could offer reasonable assurance against electrical connections overheating. Setting the thermostats high so that running time is reduced but humidity is controlled is another consideration. And being sure there is no combustible dust accumulation in the vicinity of the a/c components and any fuses can't hurt.

I'd be interested if 'spcooling' posts comments here as he deals professionally with a/c systems and likely sees all sorts of "occurrences". One thing I have always thought about is the possibility of dual cooling water intakes, say on opposite sides of the hull. That would pretty much negate a blockage of cooling water unless a boat is left for consecutive weeks or months.

Another possibility is the use of a flow meter (like Aqualarm) could be utilized to shutdown an a/c compressor immediately if cooling water is obstructed. But such a sensing system is NOT so easy to design yourself because the Aqualarm is in the closed/alarm position until water flows at start up. Is any such system shut down system available commercially?

 

[z28jimi]

All good points, and I appreciate your input. I'm in a marina, and the water is generally quite clean, but I have seen the occasional plastic bag floating by. My major source of concern is the condition of the hoses in the system. Until I get time to change them all out, I'm dealing with hoses of unknown age on a 20 year old boat. I can just imagine what would happen if one of them blew mid-week.
Dehumidification would be a welcome benefit of leaving the A/C on, but I feel that a blown hose would pretty quickly re-humidify the whole boat. I may actually look into a small dehumidifier as one of our dock neighbors has done.
I do have some buildup of gunk in the strainer basket, but then I've only opened it once so far, so it's hard to tell if it was there when we bought it, or is new. I was told that bromine in still water would not do the system any good, with possible corrosion issues or hose deterioration as you mentioned. The copper strip idea was to act as a biocide inside the strainer only, and I guess it would help the rest of the system when it is turned on.
I'd really be interested to hear how anyone else addresses this.
I don't think my cojones are going to grow big enough to let me leave the A/C on during the week while I'm at home an hour away from the boat.

 

[carolinacoast]

we replaced our original thermostat controllers with the cruisair smx2 controllers. the digital controller will shut the compressors down if a HI pressure condition occurs. that is usually the strainer. the salon goes first since it is a bigger unit and the longest run. I leave the units on 'dehumidify' and set the salon to fire every 2 hours. the others are set on 4 hour schedule during the summer. in savannah all of my neighbors do something similar or we would all have mold on our soft goods. all of my hoses are double clamped and in good condition. when a leak starts, it has been a pinhole, and I change out the hose and check the thru hull. I did add a second strainer and raw water pump inline so I can valve over to a clean strainer, or have someone else do it for me if I am away. the back up pump is peace of mind with the family onboard and bugs outside. flick the switch, 2 valves and the second pump fires up. it seemed wasted in the box. I had a similar setup (without the backups) on a smaller sailboat going back about 10 years without any problems so far.

 

[yachtsmanbill]

I turn off ALL breakers except pumps, and a single for the charger, just in case. I also close the AC seacocks even with new hose. When we get back to the boat from an hour drive from the house, I turn the stuff on full blast and go out for dinner. It is a little ruff during midday sun, but I deal with it. Got a dock neighbor who can turn it on with some notice? ws

 

[TopHattandTails]

It's my understaning that Hatt's have the high and low pressure shut offs so you don't cook a compressor. This is OEM on the 3 knob and digital panels im switching out the mechanical knobs this spring to Coastal Climate's

I've had the strainer clog and cause no water to the pump and the compressor shut down automatically. Not a good practice, but nice to know it works. My issue is fear if a hose break too. Changing out hoses this spring, so we will run dehumid once the panels are in and will try to set full A/C with staggered starts about 3 hours before Friday afternoon arrivals. There is also a network adapter that you can call the boat and have it fire up. Might be something to think about.

 

[REBrueckner]

You guys are talking raw water hoses, right? There is virtually no pressure on them so the risk of a leak should be negligible.....give each one a moderate yank with one hand...if it doesn't crack or break or feel "hard" it should be ok until replaced.

A typical DD engine system operates with a pressure of about 8 psi, and an auto, what like 25 or 30 psi, about the same as your domestic water system aboard. So maybe a 1psi in a raw water system is a virtual "no worry" situation IF your hose clamps are good.

But don't interpret me as suggesting running unattended a/c systems....I'm just saying the hose part seems pretty low risk to me.

 

[Mike36c]

I'm chicken too so I went another route. Soleus makes a nice dehumidifier for less than $200 delivered from Amazon, it very quiet and uses little power (about 300 watts when compressor is running) The first week in use it removed about 25 pints/day with the humidistat set @ 50% ( S. FL ) now it's about 10 pints/day.

 

[REBrueckner]

Mike, dehumidifier....That's also what I did aboard my own boat. But I did not face long term tropical humidity levels either. A disadvantage of the portable dehumidifier is that it may not get all areas of the boat adequately....especially if a two level MY with only a staircase connecting.... and draining collected moisture can be a hassle. I had a press on hose from the dehumidifier routed to my shower drain to eliminate having to dump the dehumidifier container.

A dehumidifier is just a small air conditioner type system..... which draws warm humid air over a refrigerated coil......and is able to precipitate moisture from the air.

Carolina's post regarding a digital control arrangement is another option that will be less expensive than running direct air conditioning.