Cruisers Forum
 


Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 03-06-2023, 15:56   #1
Registered User

Join Date: Aug 2016
Posts: 5
Priming my March pump and AC

Hi, I thought I would try this. Every time I leave the slip ie I unplug from the shore and shutting off the AC, my AC/pump loses the prime and I have to go the the aft birth dig through the floor reaching my pump and re prime it when I get to a dock or go on my gen set.

Any ideas. March pump says that he problem is not their pump.

It is a new unit since Jan 2022 when I bought this 2011 Catalina 355. Lol AC worked then, but it was January and I didnít really use it after I left the sales dock. Ever since itís been a problem.

Any help or suggestions are welcome
grnoles2 is offline   Reply With Quote
Old 03-06-2023, 16:36   #2
Registered User

Join Date: May 2015
Location: Muskegon, Mi
Boat: Columbia 36
Posts: 1,070
Re: Priming my March pump and AC

Probably the location of the intake through hull and the shape of the hull are causing the water to be sucked out and replaced with air. Not much you can do about the location but a scoop shaped through hull or through hull screen, facing forward, might tend to force water in rather than sucking it out.
capt jgw is offline   Reply With Quote
Old 03-06-2023, 16:40   #3
Registered User

Join Date: Feb 2011
Location: Pecan Grove, Oriental, NC
Boat: Hunter 27
Posts: 61
Re: Priming my March pump and AC

I close the air conditioner raw water seacock when I am going sailing. This prevents air from getting to the March pump when the boat is heeled and banging into waves.
misssherry is online now   Reply With Quote
Old 03-06-2023, 16:51   #4
Registered User

Join Date: Apr 2022
Posts: 186
Re: Priming my March pump and AC

Quote:
Originally Posted by misssherry View Post
I close the air conditioner raw water seacock when I am going sailing. This prevents air from getting to the March pump when the boat is heeled and banging into waves.

Yup--do the same.


And, if prime is lost, open thru hull, and with a hose, reach over the side of the boat and force water into the outlet. It will backfill the system and prime the water pump.
Wolfe10 is online now   Reply With Quote
Old 03-06-2023, 17:26   #5
Registered User

Join Date: Aug 2016
Posts: 5
Re: Priming my March pump and AC

That’s a new idea. It’s a long reach but may be better than destroying my aft bunk area every time I move. Thanks I’ll try this. Actually both. I tried the sea cock once and it did not work. Thanks. Though. I’ll try again. I also added new hosing so maybe that will help.
grnoles2 is offline   Reply With Quote
Old 03-06-2023, 17:54   #6
Registered User
 
cr180's Avatar

Join Date: May 2015
Location: Chattanooga, Tn./New Smyrna Beach, Florida
Boat: 1980 Gulfstar 47 Sailmaster
Posts: 329
Re: Priming my March pump and AC

I installed a self priming air conditioning pump made by Shurflo. Solved problem.
cr180 is offline   Reply With Quote
Old 03-06-2023, 18:38   #7
running down a dream
 
gonesail's Avatar

Join Date: Mar 2006
Location: FLORIDA
Boat: cape dory 30 MKII
Posts: 3,007
Images: 7
Send a message via Yahoo to gonesail
Re: Priming my March pump and AC

any way to position the pump a little further below waterline.
__________________
some of the best times of my life were spent on a boat. it just took a long time to realize it.
gonesail is offline   Reply With Quote
Old 03-06-2023, 18:42   #8
Registered User

Join Date: Jan 2023
Posts: 915
Re: Priming my March pump and AC

If your March pump will not prime, your plumbing is not correctly designed.

All piping from the thru-hull to the pump, and from the pump on the the AC NEEDS to flow uphill. If there are ANY downhill sections, a bleed valve will be required on the pump outlet. The March pump can NEVER suck water up from the ocean if it is full of air. If the air can not flow out of the pump--on its own, you are always going to have a problem. This is (or should be!) made clear on the installation diagram for every marine AC unit.

Sounds like whoever installed your AC unit didn't know this, or didn't think it was important.
SailingHarmonie is offline   Reply With Quote
Old 04-06-2023, 01:16   #9
always in motion is the future
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 17,474
Re: Priming my March pump and AC

I have a fresh water line with valve connecting between seacock and pump. I use it to flush and to prime: close seacock, open valve, start A/C, wait until sound of air bubbles is gone, open seacock, count to 5, close valve of freshwater, done.

I use the same connection for running barnaclebuster through the system, with a piece of hose looping back from the A/C unit instead of dumping overboard.
__________________
ďItís a trap!Ē - Admiral Ackbar.

s/v Jedi is offline   Reply With Quote
Old 04-06-2023, 05:48   #10
Registered User

Join Date: Oct 2014
Location: Charleston, SC
Boat: Pearson 424
Posts: 210
Re: Priming my March pump and AC

A little off topic here but, Jedi are you using your ac pump to circulate the barnaclebuster? I’ve always removed that pump from the system and used a cheap(er) pump to circulate the mixture for fear of ruining my ac pump. I’d rather not go through all that hassle if it’s safe just to use my ac pump.
sorry for the thread drift
Spindrift NH is offline   Reply With Quote
Old 04-06-2023, 06:55   #11
Registered User

Join Date: Aug 2016
Posts: 5
Re: Priming my March pump and AC

Can you advise the model number. Thanks
grnoles2 is offline   Reply With Quote
Old 04-06-2023, 06:56   #12
Registered User

Join Date: Aug 2016
Posts: 5
Re: Priming my March pump and AC

Thank you.
grnoles2 is offline   Reply With Quote
Old 04-06-2023, 08:10   #13
always in motion is the future
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 17,474
Re: Priming my March pump and AC

Quote:
Originally Posted by Spindrift NH View Post
A little off topic here but, Jedi are you using your ac pump to circulate the barnaclebuster? Iíve always removed that pump from the system and used a cheap(er) pump to circulate the mixture for fear of ruining my ac pump. Iíd rather not go through all that hassle if itís safe just to use my ac pump.
sorry for the thread drift
No, I use a small bilge pump in the bucket with solution, pushing it through the pump. I would pump it, but donít want to run the A/C, heating up the solution

I do zip-tie a sock to the return hose to catch the shells coming out. I learned to remove it when a ball of shells has formed in there because if you donít, it all gets dissolved, neutralizing the acid.
__________________
ďItís a trap!Ē - Admiral Ackbar.

s/v Jedi is offline   Reply With Quote
Old 04-06-2023, 11:55   #14
Registered User
 
CaptTom's Avatar

Join Date: Apr 2004
Location: Southern Maine
Boat: Prairie 36 Coastal Cruiser
Posts: 2,899
Re: Priming my March pump and AC

Back to the OP's question, in my last boat I put a "T" in the hose near the pump. I ran a hose from that vertically until it was up above the waterline, and in spot which was easy to access. On the top of that I put a ball valve.

Opening the valve released the air which had been trapped in the hose around the pump, to be replaced by water flowing in from the thru-hull. Close the valve again and the pump is primed and ready to go.

I agree that, in a perfect world, the hoses all run uphill from the thru-hull, but reality has a way of intruding in these things.
CaptTom is offline   Reply With Quote
Old 04-06-2023, 12:05   #15
Registered User

Join Date: Aug 2015
Location: N/A
Boat: N/A
Posts: 40
Re: Priming my March pump and AC

I replaced a Shurflo and installed a Marchpump.
Had the same problem, - resolved it by adding a oneway/checkvalve on the pump outlet.
Works great, just needs to be primed one time at start of the season.
Be Free Sailor is offline   Reply With Quote
Reply

Tags
arc, pump

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
electric priming pump, well, not priming tipsyravensaili Electric Propulsion (EP) 8 01-09-2019 04:57
MD7A water pump not priming terah Engines and Propulsion Systems 21 18-04-2015 09:24
Electric Priming /Back up Fuel Pump sailorchic34 Engines and Propulsion Systems 32 17-12-2014 12:30
Self-Priming Pump won't Prime! chad.lawie Plumbing Systems and Fixtures 12 29-10-2014 05:24
Fuel Priming Pump DeepFrz Engines and Propulsion Systems 10 04-06-2008 12:02

Advertise Here


All times are GMT -7. The time now is 17:00.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.