Air Conditioning Water Intake and Discharge

[britinusa]

Looking closely into installing AC (did this on our C250) I have a couple of questions...

I'm hoping I can install the AC without pulling the boat and making new holes in the hull.

?#1: Would it be ok to use one of the existing thru hulls by putting a T connector inboard of the shut off valve ? eg. connect the AC intake to a T in the Engine Intake line or the Head flush intake line? (I do not see an occasion when the engine would be running when we had AC turned on.)

?#2: Is there an existing thru hull that could be used to T into for the AC Discharge pipe?

From reading the many posts here about installing AC, I figure on installing the unit under the V-Berth stbd side just in front of the Hanging locker. Installing a Venturi for the condensate discharge connected to the AC discharge hose, and running the two hoses along the stbd side behind the Galley and the Stbd Water tank then into the area of the existing thru hulls in the Head locker.

I'm considering running the Air supply up behind the V-Berth Hanging locker to a 'box' on the top that would provide a grill for both the V-Berth and another facing into the cabin through the Forward bulkhead, and an Air T below the top of the hanging locker and then run inside the Storage shelving above the cabin stbd seating, Galley and into the Aft Berth with a Grill on the Aft bulkhead inside the Aft berth.

Does that sound ok?

Paul

[sailaway]

I installed my ac under the vberth and used the useless drawer as a cold air return. The pressure side I put a T in the line and went up to the counter on top of the v-berth. Then went threw the bulkhead under the seete for a second outlet. V-berth main cabin are cool. All my air ducts are 6 inches. I drilled new holes for seacocks. Charlie

[britinusa]

Thanks Charlie.

I would be ok with putting new thru-hulls in the v-berth except for the expense of hauling the boat out for a 2nd time in 2 months 

Right now I'm favoring running the two hoses from the V-Berth down the port side at the back of the seat lockers to the head and then T'ing them into the Head Raw Water hose (inlet) but have not figured out a discharge route yet 

Still figuring.

Paul

[Mike and Joanne Stimmler]

Paul,
I don't know if this is the best idea but I think I've read that some peoples just run the discharge line into the bilge. Possibly a temporary solution until the next haul out but I'm sure we'll get some other opinions. Another thought was the ice box drain line.

Mike

[Exodus]

DO NOT run the discharge line to the bilge.  Not only is that a terrible idea, but it could possibly sink your boat.  The discharge is putting out 3-4 gallons per minute, this would fill the bilge rather quickly and God forbid your bilge pump were to quit working.

[Roc]

This is the thing to have for the discharge:
http://www.mmair.com/marine_division/accessories/mermaid_condensator

Kind of pricey...  I bought one YEARS ago when it was about $75......

[DaveM]

I use one of these for the discharge on a 16,000 BTU unit and it does great.  I found it a much cheaper alternative.  Just google it.

http://www.mazzei.net/files/684.pdf

Good Winds
DaveM

[chuck53]

DO NOT run the discharge line to the bilge.  Not only is that a terrible idea, but it could possibly sink your boat.  The discharge is putting out 3-4 gallons per minute, this would fill the bilge rather quickly and God forbid your bilge pump were to quit working.

OK, is the OP talking about water pump discharge or condensate discharge?  Agree, that water pump discharge into the bilge is a very bad idea, but I'm guessing the OP is talking about condensate discharge.  I run mine into the bilge, maybe a couple gallons a day and no problems.

[Mike and Joanne Stimmler]

Exodus,
Wow, I didn't know it put out that much water. I thought it was just a condensate line. So sorry for the mis-information.

Mike

[chuck53]

You have 2 sources of water, your sea water cooling which can easily be 2-3 gallons a minute and your condensate which is more like 2-3 gallons a day. 
Your seawater discharge is usually pretty close to your AC, out the side of the boat, maybe 1-2 feet above the water line. 

[pablosgirl]

Hi Paul,

You can use one of the existing thru hull fittings as a temporary solution but it would be better on the pump to have the inlet thru hull in the v-berth area.  The cooling water discharge should just go out the side of the boat about 1.5 feet above the water line.  This will remove any back pressure on the pump from pushing the discharge water against the water the boat floats in.  You will also need to instal a sea strainer that is rated equal or greater than the flow capacity of your cooling water pump to prevent clogging the heat exchanger in the AC unit.  Our condensate line drains into the bilge and does not place more than 2-3 gallons of water into the bilge in a day.  I have been meaning to buy the fitting that sucks the condensate water out the discharge line, but they were pricy.

You will lose a fair amount of storage space by running the air supply for the aft cabin down the stbd. side.  Do you use the aft cabin for sleeping?  We use the forward cabin to sleep in and use the aft cabin for guests and to store things on long cruses.  We have a fan in the aft cabin that moves cool air from the main cabin (leaving the aft cabin door open ).  We have a 16,000 BTU unit under the v-berth and a T in the supply duct that feeds an air box that is on top of the port drawer unit that ducts air into the v-berth and through the bulkhead into the main cabin.  On the stbd. side there is a box on top of the hanging locker cabinet that ducts air into the main cabin as well.  We find that this works well for us here on the Texas coast, but your situation may be different.

Paul & Cyndi

[britinusa]

Thanks Paul & Cyndi,

We're hoping that our kids & grandkids will spend some time on the boat, so, yes, we plan on using the aft berth for guests.

Your points about the pump pressure are very well taken.

Back to the drawing board. 

Paul & Peggy

[chuck53]

OK, here's what we did.
We put the unit in the cabinet next to the nav. station.  Since we didn't have a Y-valve coming off the head, the old discharge thru hull wasn't being used, so we used it for the water supply.  No new thru hull to drill.
We only have one very short duct coming thru the vented door and the rest of the door acts as a return.  We have no ducts going to either the fore or aft cabin.
Now, on hot, sunny days, those 2 cabins can still get toasty, but I can get the salon down to a very comfortable temp.  Once the sun sets, the sleeping cabins start to cool nicely. 

[britinusa]

Thanks Chuck,

Vacillating about the choices.

Methinks that a compromise might be using the head inlet supply via a Y connector will take care of the inlet, but I'll have to put a hole in the hull above the water line for the AC discharge with a Venturi to suck out the Condensate.

That route would avert having to pull the boat just to install the AC and keep the pump back pressure down with the short discharge route.

Here in South Florida the heat demands (for us anyway) that we cool the V-Berth & the Aft berth as mentioned.

So unless anyone really wants to mess with my head (no pun intended) I think we're going to install as follows:

• Put the unit on a new shelf on the Stbd side under the V-Berth just forward of the hanging locker
• Use the head raw water inlet as the AC Supply inlet via a Y connector
• Drill a new Thru Hull in the V-berth above the water line for the discharge and venturi for condensate extraction
• Run Duct work Stbd up inside the hanging locker - to an outlet above the top shelf and also into the Cabin stbd side
• Run Duct work Port side behind the v-berth drawer unit to an outlet above the top shelf and also into the cabin port side
• Run Duct work Stbd side behind the outboard storage cabinets (ours have doors) then aft into the Aft Berth

I'll follow Don Casey's process for installing the Thru Hull.

Will report on progress 

Paul & Peggy

[Roc]

Paul,
You should put a seacock in the discharge hose right before it exits the hull.  This way you can close off any water that can come into the boat while your sailing, or for any other reason.  It is a safety margin to close off a "hole" in your boat.  That's how I installed the discharge hose on my boat.

http://www.forespar.com/boat-marine-plumbing-ball-valve-seacock-oem.shtml