Salt water pump continuous flow 110volts for air conditioning recommendations

[basenay]

Looking for recommendations for reliable 110 v AC salt water pump for my AC system. For most of the last 26 years have used Little Giant 900-1200 GPH pumps which the first lasted 10 years, next 5 yrs then <2 yrs then the last 4 months. Two year warranty worthless since seldom back to USA. AC works great but once stop using system for several months then restart seems to be shortly thereafter pump fails whether mounted in air or wet in bilge. Completely sealed units so impossible to be sure cause of failure[ ? overheat which then leads to leaking of internal oil or vice versa]. All hoses of for cooling water checked multiple times and are clear. AC running well now with back up inexpensive swimming pool pump that is mounted on floor under nav. station as too large and not rated for possible wet conditions.

What pumps are others using and how long do the typically last?
Thanks in advance for input.
Bruce
s/v DreamCatcher
IP45-03
lying Marina Vallarta
Puerto Vallarta, MX

[Westcliffe01]

https://www.mcmaster.com/water-centr...2409678015701/

Curious why such a high flow rate ? Water has a tremendous heat transfer capacity. The flow rates you refer to are well in excess of what is required to cool a 6.4l turbodiesel engine in high ambient conditions.

The magnetically driven centrifugal pumps have to be mounted below the waterline so thàt they are primed by static pressure but other than that, they should give great service. Plastic so no corrosion issues. Some models only accept garden hose fittings, so don't pick those.

[a64pilot]

Recommended flow rate for a Webasto 16k AC is 6.6 gl per min
That’s 400 gl an hour, pumps are not rated for any plumbing loss etc, it’s likely that a 900 GPH pump only pumps real world 400 GPH, so a wise decision in my opinion.

The best AC pumps in my opinion are March pumps, they seem to last decades, even under heavy use.

Webasto sells what’s appears to be a knock off of the March AC pump, I’m running one on my front AC, I’ll let you know in five years, but gut says it’s likely just as good.

[Sailmonkey]

We’ve got a tiny little iwaki pump on our 5k btu unit.

It’s 9 years old now and just works. But.....it’s not been used full time ever. A week here and there.

[glcalahan]

I just replaced a Dannar Mfg model #, $89 USD....700. Centrfical magnetic pump. Works great.....

[singlespeed]

March makes a mag drive pump that works ready well. Label fell off mine some years ago, so specific model is uncertain. Like all pumps, exercise the pump at least monthly, more often in warmer waters.

[Bill whitmore]

I've has my March sealed centrifugal pump for 25 years of intermmittent use with 6 of those years full time use in the tropics and three diiferent AC units. It sits in the bilge and is frequently soaked in SW....still running fine!

[fortyninegroup]

This is what we have on our SO 409 - it feeds two AC units and has been reliable here in South Florida where the AC is on most months of the year - https://www.defender.com/product.jsp?id=2205918

[Coolerking]

The pumps size needs to be matched to the total BTU capacity of the ac system, with loss due to plumbing and hoses.
We use a few different ones, 250, 500, 1000 gph.
Webasto has a high gph number if they do actually use 6gpm.
We use a max 4.5gpm flow rate to keep the water flowing smoothly, eliminating cavitation.
4 gpm per 12k btu/h is the norm with zero loss.

[SVHarmonie]

There are a plethora of industrial pumps suited to marine AC usage.

A couple criteria to look for:

• Magnetically drive, so no seals to leak.
  
• A motor that is at least TEFC (Totally, Enclosed Fan, Cooled) No "drip-proof", and certainly no open frame!
  
• Of course matching the flow rate and head capacity you need.
  
• Continuous duty
  
• If you can not mount them in a place that is reliably dry and free of water puddles, spray or mist, then you pretty much have to go with one of the submersible models.
  

Some of the motors will be capacitor start, and if so it is worth having a spare capacitor (or 2) deep in your spare parts bag. They are cheap, and a failed cap is by far the most common failure for motors that have them.

We have a pair of Italian made Eno mag drive pumps that (other than replacing the start capacitor) have run for 12 years, and a March water cooled pump that has run for 2 years.

Two things tend to kill these mag drive pumps. First is running dry--even a little. Second is pumping water with a high sand or silt content.

In both cases the failure mode is similar, the spinning impeller wears away the plastic housing, and seawater ends up in the pump motor. The first one you can do something about with proper plumbing, the second you are kind of stuck with.

[a64pilot]

I’m not sure how you get water in the motor of a magnetically driven March pump, there is no connection between the two, no shaft etc. drive is through a magnetic coupling.

I don’t think all March pumps are hermetically sealed and submersible, the ones I use are, but the bigger ones don’t appear to be.

Recommended flow rate for Webasto 16k is 6.6 GPM, see attached pic.
But remember a strainer and several feet of hose plus any 90’s you may have in the system can easily cut the flow rate in half, especially with a half clogged strainer.

[basenay]

Thanks all for the replies.

Will check out the Ena.

Found this in my searching: MARCH PUMPS–Seawater Circulation Pump 1000gph 115V For 45000Btu Systems reviewed on West Marine. "High failure rate
Our boat is in Mexico full time, where the line voltage is typically around 135VAC. These pumps are susceptible to overheating at that voltage and they tend to fail in less than 1 year." Koolair pump similar to March pump had lots of negative reviews on Amazon.

Having been in Mexico 4 1/2 yrs line voltage does vary marina to marina and different days but never seen 135 yet. Is this likely the cause of frequent pump failure?

[Coolerking]

There are 2 types of march pumps that we use, they are either air cooled open frame, the AC3 series for instance, and the LC3 series which is a water cooled submersible style with an epoxy encased motor, the cooling tubes will occasionally fail and then it burns up. this is caused by a pump running dry and overheating the case and the seals.
They are not self priming.
I have seen these pumps run for many many years without issues when they are properly installed and cared for.
I have also seen them destroyed in weeks.

[slug]

Originally Posted by Bill whitmore

I've has my March sealed centrifugal pump for 25 years of intermmittent use with 6 of those years full time use in the tropics and three diiferent AC units. It sits in the bilge and is frequently soaked in SW....still running fine!

Yah

March .. they last forever

Not self priming so careful with location on a sailboat

[EmeraldCoastSailor]

March pumps are great