Reply
 
Thread Tools Display Modes
 
Old 06-02-2013, 08:53 PM   #1
Guru
 
CaptTom's Avatar
 
City: Southern Maine
Country: USA
Vessel Name: Cygnus
Vessel Model: Prairie 36 Coastal Cruiser
Join Date: Dec 2012
Posts: 1,373
A/C intake manifold

This past weekend elevated my Air Conditioning install to a higher priority. I've figured out where to locate the two units I bought, the wiring is done and I have two discharge through-hulls already plumbed up.

The problem is the water intake. I've got a spare heavy bronze through-hull with a 90 degree 1-1/2" barb connection on it. I'd rather not try to unscrew the 30-plus-year-old fitting out from the through-hull while the boat is in the water, for obvious reasons. But I've verified that the valve opens and closes well.

What I need is some sort of manifold or "Y" connector to get from the through-hull to the two 5/8" barb fittings, one on each of the two sea strainers, which will feed the two sea water pumps (also 5/8").

I found a nylon 1-1/2" barb "T", but not a 1-1/2" to 5/8" barb reducer.

Any ideas?
__________________
Advertisement

CaptTom is offline   Reply With Quote
Old 06-02-2013, 11:10 PM   #2
Senior Member
 
HenryD's Avatar
 
City: Heading south for Ft. Myers
Country: USA
Vessel Name: Seven Tenths
Vessel Model: Mirage / Great Harbour 47
Join Date: Dec 2012
Posts: 353
How far apart are the units going to be installed? On my boat, the water flows to one A/C unit, and then flows through the 2nd unit before going over the side.
__________________

HenryD is offline   Reply With Quote
Old 06-02-2013, 11:27 PM   #3
Guru
 
HopCar's Avatar


 
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 3,505
Tom, why are you reluctant to unscrew the 1-1/2 hose barb?

Do you have a flanged seacock or are you dealing with a ball valve screwed onto a thru-hull fitting?

If you have to use the 1-1/2 hose barb, you can use a short length of 1-1/2" hose to conect to an 1-1/2 hose barb screwed into an 1-1/2" pipe tee. Put bushings into the other two outlets on the tee to reduce them to 1/2" female pipe thread. Both Groco and Perko make 1/2" mpt X 5/8" hose barb bronze fittings.

What I've described is a really ugly way to do it.

You really need to get that 1-1/2" 90 deg hose barb out to do it right.
HopCar is offline   Reply With Quote
Old 06-03-2013, 06:01 AM   #4
Guru
 
CaptTom's Avatar
 
City: Southern Maine
Country: USA
Vessel Name: Cygnus
Vessel Model: Prairie 36 Coastal Cruiser
Join Date: Dec 2012
Posts: 1,373
Here's a picture of what I'm dealing with:


I guess my fear is the unknown, will the threads stick, will I end up turning off the top of the through-hull, instead? Will something break or give way? I don't want to end up with an emergency haul-out because of this project.

None of the boat stores near me have a very large selection of fittings, and their on-line catalogs don't seem to list many parts. I'll look up the Groco and Perko part numbers and maybe they can order them. I'd hoped to have A/C within a week, but it looks like this is turning into a long-term project.
CaptTom is offline   Reply With Quote
Old 06-03-2013, 06:44 AM   #5
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,524
Go to the box store and purchase a hose to pipe barb and a brass T fitting.

Bronze is better but hard to locate.

Short piece of 1 1/2 hose to the T.2 marine hose clamps each end.

Use bushings to mount 2 valves , SS ball OK, and then adapt from the valve to the AC supply hose.

About a half hour after you get the parts, your done.

Bronze T might eventually come from a better marine supplier.

The T might want to be on a longer hose (to above the WL) as you will at times need to remove it and ram the hose/thru hull with a hunk of old garden hose to clear debris or jellyfish.
FF is offline   Reply With Quote
Old 06-03-2013, 09:43 AM   #6
Guru
 
BobH's Avatar
 
City: Montgomery, TX
Country: USA
Vessel Model: None, but looking
Join Date: Feb 2012
Posts: 778
Is there a raw water pump for each unit? I have two A/C units but a single high capacity pump and strainer to feed both units.

Bob
BobH is offline   Reply With Quote
Old 06-03-2013, 09:59 AM   #7
Guru
 
CaptTom's Avatar
 
City: Southern Maine
Country: USA
Vessel Name: Cygnus
Vessel Model: Prairie 36 Coastal Cruiser
Join Date: Dec 2012
Posts: 1,373
Thanks FF, I'm going to try to hunt down some of those parts. You're right that fitting them all together will be the easy part. Figuring out what to get and where to get them is the challenge.

Bob, I already have the two 500GPH pumps, so I'm going with the redundancy theory at this point. Your set-up is probably safer in the end because there are fewer fittings, hose clamps, adapters, etc. below the waterline.

A/C pumps like to live below the waterline since they're not self-priming. I was planning to put a manual vent somewhere higher up so that if the pumps do get air-bound, it's just a matter of opening a valve and they'll fill to the water line. That little feature saved me many hours of frustration on my last boat.
CaptTom is offline   Reply With Quote
Old 06-03-2013, 12:46 PM   #8
Guru
 
CaptTom's Avatar
 
City: Southern Maine
Country: USA
Vessel Name: Cygnus
Vessel Model: Prairie 36 Coastal Cruiser
Join Date: Dec 2012
Posts: 1,373
The hunt was successful. First I tried Lowe's. Nothing over 1" in brass, and even then slim pickings. Next was the plumbing supply store. Only took a few seconds to explain what I was trying to do, and the guy came back to the counter with the 1-1/2" tee, two bushings and the 1-1/2" NPT to barb adapter. He didn't have the 5/8" barb adapters.

Next to WM. I found the two adapters and picked up some hose.

That part's done. Now to find a nice, neat way to pack all this out of the way in my engine room.
CaptTom is offline   Reply With Quote
Old 06-04-2013, 05:45 AM   #9
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,524
Now to find a nice, neat way to pack all this out of the way in my engine room.

Not so out of the way that clearing it , with out accessing the sea cock ay 0 dark 30 , will be too big a hassle.
FF is offline   Reply With Quote
Old 06-04-2013, 07:35 AM   #10
Guru
 
CaptTom's Avatar
 
City: Southern Maine
Country: USA
Vessel Name: Cygnus
Vessel Model: Prairie 36 Coastal Cruiser
Join Date: Dec 2012
Posts: 1,373
Good point. I probably spent an hour last night just looking, measuring, sketching, and scheming. I also put a big pipe wrench to the through-hull tailpiece just for fun. Couldn't even budge it. I decided against going back and trying again with a cheater bar. No telling what might give first.

So, my plan now is to mount the pumps and strainers on a board that will fit snugly in a little outboard corner of the engine room where an obsolete shower drain pump now sits. I should be able to clear the strainers relatively comfortably by laying across the battery box cover. From that same position I can easily manipulate the seacock on the through-hull.

Both shower drain pumps (fore and aft) are being replaced by new shower sumps, to be located in the bilges amidships somewhere between the showers and the new A/C units, so they can take both the shower water and the A/C condensate.
CaptTom is offline   Reply With Quote
Old 06-04-2013, 09:56 AM   #11
Guru
 
BobH's Avatar
 
City: Montgomery, TX
Country: USA
Vessel Model: None, but looking
Join Date: Feb 2012
Posts: 778
With those two big 500gph pumps I would be concerned that if one pump is off, the other one would pull the water out of the other unit and suck air through the discharge line. I guess it really depends on how free the intake flow is.

Bob
BobH is offline   Reply With Quote
Old 06-04-2013, 10:56 AM   #12
Guru
 
CaptTom's Avatar
 
City: Southern Maine
Country: USA
Vessel Name: Cygnus
Vessel Model: Prairie 36 Coastal Cruiser
Join Date: Dec 2012
Posts: 1,373
I see your point. I'll leave room for check valves.
CaptTom is offline   Reply With Quote
Old 06-05-2013, 06:29 AM   #13
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 16,524
I see your point. I'll leave room for check valves.

Might be simpler to simply throttle the pump with the installed ball valve.

Figure a way to lock the handle in place , or better use a different style valve with finer adjustment that doesn't shake to a different position.
FF is offline   Reply With Quote
Old 06-05-2013, 09:05 AM   #14
Guru
 
City: Hotel, CA
Country: Fried
Join Date: Sep 2011
Posts: 8,328
Sounds like a good place for a circuit setter balance valve. Set desired flow then snug down the set screw so the setting will not easily change.
Attached Images
 
__________________
Craig

It's easier to fool people than to convince them that they've been fooled - Mark Twain
CPseudonym is offline   Reply With Quote
Old 06-05-2013, 09:35 AM   #15
Scraping Paint
 
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
Quote:
Originally Posted by CaptTom View Post
I guess my fear is the unknown, will the threads stick, will I end up turning off the top of the through-hull, instead? Will something break or give way?

This thread is starting to get really silly now with proportioning valves, multiple pumps, throttling seacocks and who knows what next.

Use one large pipe wrench or a proper sized wrench on the flats to hold the seacock and another pipe wrench to turn the barb fitting. Use a length of pipe stuck inside the barb to gain leverage and if that doesn't work easily, use a propane torch to heat the barb then try it again. It will unscrew without doing any damage.

Why 2 pumps? Is airconditioning a critical system? Why add complexity and cost?
RickB is offline   Reply With Quote
Old 06-05-2013, 09:39 AM   #16
Guru
 
motion30's Avatar
 
Join Date: Jan 2010
Posts: 740
I have two units a 16000 and the 12,000 BTU they both are cooled and work fine with 1 500 G p H pump
motion30 is offline   Reply With Quote
Old 06-05-2013, 09:40 AM   #17
Guru
 
BobH's Avatar
 
City: Montgomery, TX
Country: USA
Vessel Model: None, but looking
Join Date: Feb 2012
Posts: 778
>>>Why 2 pumps? Is airconditioning a critical system?<<<

It sure is if you live in Texas. I just converted my two systems to run off one pump. One seacock, one strainer, one pump.

Bob
BobH is offline   Reply With Quote
Old 06-05-2013, 10:33 AM   #18
Scraping Paint
 
City: Fort Lauderdale
Vessel Model: CHB 48 Zodiac YL 4.2
Join Date: Oct 2007
Posts: 3,804
A crtical system is "the equipment or technical systems that the sudden operational failure of may result in hazardous situations."

A sweaty grumpy wife may be a relationship hazard but the loss of airconditoning does not put the vessel at risk.
RickB is offline   Reply With Quote
Old 06-05-2013, 10:49 AM   #19
Guru
 
LarryM's Avatar
 
City: League City, TX
Country: USA
Vessel Name: Pelago
Vessel Model: Wellcraft 3300 Coastal
Join Date: Aug 2011
Posts: 843
CaptTom,

You did not mention the size of your A/C units, so unless you have a pair of 16,000btu systems, you could be a good candidate for a single 500gph pump system like BobH and Motion30 described.

For most current marine A/C systems, the raw water requirement is 200gph/ton at temperatures up to 100F. One ton is 12,000btu so a 500gph pump would theoretically be able to supply about 30,000btu of A/C capacity. Pump output capacity is normally measured at 1' head, so if you have any long hose runs, elbows, reducers etc., the flow will be reduced somewhat. Make sure the condensing coils in your units are clean and use a quality high capacity raw water strainer. You will need to connect the pump power leads to both systems so that either will be able to energize the pump when needed. Some systems require a relay box for this, but I think most modern controls have a dedicated power connection for pump power.

A single pump would certainly make for a cleaner installation and be easier to service.

Good luck!
LarryM is offline   Reply With Quote
Old 06-05-2013, 11:09 AM   #20
Guru
 
City: Hotel, CA
Country: Fried
Join Date: Sep 2011
Posts: 8,328
Quote:
Originally Posted by RickB View Post
A sweaty grumpy wife may be a relationship hazard but the loss of airconditoning does not put the vessel at risk.
Depends upon that sweaty grumpy wife's ability to curtail the use of the boat, could be a risk of selling said boat. FTR I agree with everything you've said in this thread.
__________________

__________________
Craig

It's easier to fool people than to convince them that they've been fooled - Mark Twain
CPseudonym is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 01:29 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012