How to Size HVAC

[s/v Jedi]

Originally Posted by Stillraining

Why not Nick?

Because you're not supposed to let water into your bilge. Your bilge pumps are for emergencies, not for dealing with running A/C.

If there wouldn't be another easy solution I might understand it but that isn't the case. I just had to install a couple of feet of 3/8" hose to a near-by sink and if you don't have that, you have the raw water discharge hose right there and these simple fittings let you get rid of it that way.

cheers,
Nick.

[Joli]

Kind of as an aside. Anyone here usig a chilled water system? For bigger boats they seem to make sense, no 4 or 6 inch ducting to run.

[Stillraining]

Sort of makes sense i guess..But I always have some water in my bilge anyway just from what comes down the mast, as it rains allot here...so I'm afraid I will never be one of those boats with a dusty bilge...also i have a little negative slope right under the engine that if the boat sits at the dock will collect about 1/4" of water in..as soon as you go out sailing it finds its way to the deeper 18 x 10" well that the main bilge pump resides in...which itself always has about 1 to 1 1/2" or water in it due to how bilge pumps floats work.

I though about epoxing up that section to provide some additional slope to it when the engine and genset were out..but didnt do it.

So in my case I dont think it would matter a whole lot and it sounds better then a through hull...It not like it will be running 24/7.

[s/v Jedi]

Stillraining: I never advocated a thru-hull for it. Pls. re-read my message, you can get rid of it without an extra hole.

Google "Venturi Condensate drain" if you can't tap into a sink or shower drain.

cheers,
Nick.

[Stillraining]

Nope ..I know that....That was one of my original options not yours..

You miss read me..

[s/v Jedi]

Originally Posted by Stillraining

Nope ..I know that....That was one of my original options not yours..

You miss read me..

Well, one of us must have developed dyslexia and I'm afraid it's either not me or I have a severe case because I see it the other way around even if I read the thread again ;-))

ciao!
Nick.

[Stillraining]

Originally Posted by Stillraining

Regarding condensate...is it better to add a topside through hull and let it gravity flow out ( both units will sit next to the hull port and starboard) or is it better to let it run into the bilge where the pump will take care of it?

I can see a possible problem when healed over with the former method.

My intoduction of the idea

Originally Posted by s/v Jedi

I would not let the condense run into the bilge. We divert it to a gray water tank. I don't think I'd like another hole in the boat for this either. There are special "vacuum adapters" that you can install in the cooling circuit where you can connect the condensate drain to, which is what I would use when I didn't have a gray water system already.

cheers,
Nick.

You telling me its not a good idea

Originally Posted by Stillraining

So in my case I dont think it would matter a whole lot and it sounds better then a through hull...It not like it will be running 24/7.

Me agreeing another hole isint a good idea..

Better get thoes eyes checked My friend...

[s/v Jedi]

He he, we must be talking about different things. I gave a 3rd and 4th alternative after you brought the first 2 alternatives up:

1. top-side through hull as condensate drain (extra hole)
2. let flow into bilge and have bilge pump take care of it
3. drain into gray water tank or sink/shower drain
4. venturi/vacuum type fitting in raw water discharge that sucks away condensate and discharges it together with the raw water from the condenser (no extra hole)

So, we have a total of 4 options and my pref would be 3->4->1->2.

ciao!
Nick.

[Stillraining]

Forum Rule 1#

Never, ever, argue with a Dutchman.........

[captainKJ]

Lots depends on your lifestyle,,, I worked on a 120 foot sailboat,,, owners complained that the boat was always hot,,,,, to make a story short the engineer went aganst all the experts advise,,,, doubled the size of the AC,s,,,,, owners were happy,, they could leave the doors open all day and still keep the salon at 75 degrees in the Caribbean during the summer,,, the size of the AC units also depends on your lifestyle,,, personally i would rather have too much AC then not enough,, you can always let it run and crack open a window if needed

[GordMay]

Originally Posted by captainKJ

... the engineer went aganst all the experts advise,,,, doubled the size of the AC,s,,,,,
,,, personally i would rather have too much AC then not enough,, you can always let it run and crack open a window if needed

Not very good advice.

A more informed point of view is presented in this old article:
➥ Air Conditioning - If Bigger is not Better, What is?

[capn_billl]

I like a larger unit for the salon, and a smaller unit for the aft cabin. Even in Texas nights I find it is usually HOT when I go to sleep, but around 3am it is too cold and I get up to shut the AC off. I have a 12kBTU & a 12KBTU in a 36' If I had to do it again,(when I do it again), I would buy a 9K for the aft cabin. When I got the boat the Ac's drained into the bilge, this caused a lot of problems, you wouldn't believe how much water is in the air here. I bought a westmarine shower sump and installed it under the AC's, pump to graywater. I am considering putting in a Dc powered auto style AC for a quick cool when I'm not running the generator.

[Stillraining]

Forgot about this thread.

Update: We installed a 16K in the Main Saloon and a 9K in the Aft cabin...as of right now the condinsate drains to the bildge but I will see how that works out and my use Nicks advice on a venturie system to suck out with cooling water...dont plan on using it to much till we start our partical live aboard life style some years away yet anyway.

Thanks for all the input...Were not in the water yet so there goes another summer.... looks like we will be trying out the heat function of the units before the cooling function.