Cruisers Forum
 


Join CruisersForum Today

Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 10-09-2018, 11:11   #1
Registered User
 
S/V Alchemy's Avatar

Join Date: May 2008
Location: Toronto
Boat: Custom 41' Steel Pilothouse Cutter
Posts: 4,965
March Pump already on A/C circuit for use on watermaker?

A chance remark on a recent thread made me think that I could use a simple valve on my existing A/C seawater line to supply my watermaker (as yet unpurchased). It's a standard March pump feeding a Marine Air 12,000 BTU unit and is properly below the WL and is therefore self-priming off a standpipe. Fact is, I don't even use the A/C much, but I will be using the watermaker as our tanks on a full-keeler contribute to the ballasting. My pump is similar to this model:

Any objections to this approach? I have enough inverter power and battery capacity to run the watermaker on DC and the March pump via inverter. It would just simplify the plumbing in some respects.
__________________

__________________
Can't sleep? Read www.alchemy2009.blogspot.com for fast relief. Can't read? Avoid www.volumesofsalt.blogspot.com, because it's just personal reviews of sea books.
S/V Alchemy is offline   Reply With Quote
Old 10-09-2018, 11:26   #2
Registered User
 
Nicholson58's Avatar

Join Date: Jan 2011
Location: Caribbean live aboard
Boat: Camper & Nicholson58 Ketch - ROXY Traverse City, Michigan No.668283
Posts: 4,664
Images: 84
Re: March Pump already on A/C circuit for use on watermaker?

1. does the WM require a boost pump? It may be unnecessary. You may be able to locate the WM so that no boost is needed.

2. Will the 115 VAC pump supply the flow volume required? Not enough? Too much? If a boost is needed, most WM’s specify a centrifugal pump of specific capacity. A positive or fixed displacement pump may cause trouble.

3. Certainly no need to punch another hole in the boat.


Our Spectra 200T runs on 24 DC from solar. No boost pump. Intake about at the waterline but can run up to about a foot above. Pump is lower right.
Attached Thumbnails
Click image for larger version

Name:	755736A3-0F79-407D-8293-DFC57402117B.jpg
Views:	93
Size:	428.0 KB
ID:	177156  
__________________

Nicholson58 is offline   Reply With Quote
Old 10-09-2018, 12:12   #3
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 29,263
March Pump already on A/C circuit for use on watermaker?

It will easily supply enough water, question I have is will it supply enough pressure? Your looking for 5 or more PSI after both filters, usually.
March pumps are I believe high volume, low pressure pumps.
I think it will work, but not sure.
a64pilot is online now   Reply With Quote
Old 10-09-2018, 18:35   #4
Registered User
 
S/V Alchemy's Avatar

Join Date: May 2008
Location: Toronto
Boat: Custom 41' Steel Pilothouse Cutter
Posts: 4,965
Re: March Pump already on A/C circuit for use on watermaker?

The watermaker I'm looking at has an appropriate pump. Perhaps the tee-off I should use should be post-filter and pre-March pump, so I can make use of the one intake. Because if I'm making water, I don't need to have A/C, as I am likely underway and charging with the alternators.


So I may be, once again, overthinking something.
__________________
Can't sleep? Read www.alchemy2009.blogspot.com for fast relief. Can't read? Avoid www.volumesofsalt.blogspot.com, because it's just personal reviews of sea books.
S/V Alchemy is offline   Reply With Quote
Old 11-09-2018, 08:46   #5
Registered User
 
S/V Alchemy's Avatar

Join Date: May 2008
Location: Toronto
Boat: Custom 41' Steel Pilothouse Cutter
Posts: 4,965
Re: March Pump already on A/C circuit for use on watermaker?

Thanks for all the replies...
__________________
Can't sleep? Read www.alchemy2009.blogspot.com for fast relief. Can't read? Avoid www.volumesofsalt.blogspot.com, because it's just personal reviews of sea books.
S/V Alchemy is offline   Reply With Quote
Old 11-09-2018, 09:11   #6
Registered User
 
Dartanyon's Avatar

Join Date: Aug 2014
Location: Seattle
Boat: Norseman 447
Posts: 101
Images: 1
Send a message via Skype™ to Dartanyon
Re: March Pump already on A/C circuit for use on watermaker?

Alchemy, we just removed our forward AirCon (keeping the aft one) and are using the thru-hull that supplies our AC March pump. As mentioned, our March is high volume / low pressure and would not be ideal for our Cruise RO Watermaker boost pump, although it was my first thought to use that pump. We made the split just after the thruhull with 2 valves (so that there is no possibility that the Watermaker pumps could pull air back through the AirCon system). We've only had it running a couple of months but everything seems to be happy.
Dartanyon is offline   Reply With Quote
Old 11-09-2018, 10:23   #7
Registered User
 
mvmojo's Avatar

Join Date: Mar 2018
Location: www.mvmojo.com
Boat: Robt Beebe Passagemaker 49-10 in steel
Posts: 233
Re: March Pump already on A/C circuit for use on watermaker?

I use my air conditioning pump as a boost pump for my 33 gph watermaker. It's a 33 gpm Little Giant pump, valved to supply 3 air conditioners and the watermaker. The only thing you need to determine is whether your March pump will deliver (through your pre-filters) 10-15 times the water that your watermaker will make. Most watermakers only produce a max of 10% product water and ideally you'd like to keep it down to maybe 6% or so. Starving the high pressure pump is a recipe for quickly ruining the pump.
__________________

mvmojo is online now   Reply With Quote
Reply

Tags
arc, pump, water, watermaker

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
solar, 100w, open circuit ok, short circuit ok, no power to battery NotreVoyage Electrical: Batteries, Generators & Solar 3 26-04-2016 22:41
Different Wire Sizes In Bilge Pump Circuit cburger Construction, Maintenance & Refit 37 03-02-2012 06:36
Already Blown One Rule-Mate Electronic Auto Bilge Pump ! surfmachine Electrical: Batteries, Generators & Solar 3 27-04-2010 07:12
Black Point – Big Majors – March 21 – March 26, 2009 skipgundlach General Sailing Forum 0 11-04-2009 06:42
Already in the Caribbean: Journey of Makai sv_makai Sailor Logs & Cruising Plans 1 20-07-2005 01:09

Advertise Here


All times are GMT -7. The time now is 14:14.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.