Need New Air Conditioning Water Pump

May 19, 2016
119
Catalina 30 Riverside, NJ
I am looking for suggestions for a new water pump for my Air Conditioning system. I just burned out a CAL 320 for the second time; about four days out of warranty.

For some reason, my pump runs dry once a day. The Air Conditioning system alarms and then cuts off. I check the pump, no flow. I close the seacock, re-open it, and the pump primes and flow returns. I turn the Air Conditioner back on and I am good for another twelve hours.

I was looking at a SeaFlow because it's supposed to be able to run dry without damage, but the reviews are not all that good.

Any suggestions are welcome
 
Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
I have a sea flow it gets hot also. same as the March pump what size AC and lines? Yall really need to disconnect the discharge to get the air out of the pump! how high is the AC above the pump? The 250 gph only has a 3ft "head"
 
Jun 15, 2012
628
Hunter 50 AC St. Petersburg
I have had good luck with other Seaflow pumps. Appear to be well made and used to come with a 4 year warranty, which I think is now only 2 years on most products. I am surprised at burning out your Cal pump. My Dometic March pump started to leak at the back of the wet end, which could have sunk my boat. The wet end is of plastic construction and the impeller actually bored a hole in the rear housing. I replaced the entire wet end and now everything works correctly.
I think it would be a good idea to investigate the cause of the pumps loss of prime. This has not happened on my boat.
 
May 19, 2016
119
Catalina 30 Riverside, NJ
I have a sea flow it gets hot also. same as the March pump what size AC and lines? Yall really need to disconnect the discharge to get the air out of the pump! how high is the AC above the pump? The 250 gph only has a 3ft "head"
Not sure what you mean by let the air out... When I replaced it, I disconnected both the inlet and outlet lines. I hooked up the inlet line, opened the feed from the strainer, and the water came out of the pump without any power. I attached the discharge hose to the the outlet side. Secured all clamps. Powered the device and out came the water from my AC outlet from the thru-hull outside my boat. Turned on the AC and it worked... for about 12 hours. Then alarms. I close the thru hull cock, open it, it works for a few hours, maybe even a few days, then alarms again. The pump is only size inches about the thru hull inlet cock.
 
May 19, 2016
119
Catalina 30 Riverside, NJ
I have had good luck with other Seaflow pumps. Appear to be well made and used to come with a 4 year warranty, which I think is now only 2 years on most products. I am surprised at burning out your Cal pump. My Dometic March pump started to leak at the back of the wet end, which could have sunk my boat. The wet end is of plastic construction and the impeller actually bored a hole in the rear housing. I replaced the entire wet end and now everything works correctly.
I think it would be a good idea to investigate the cause of the pumps loss of prime. This has not happened on my boat.
I don't know why it loses prime. The setup is a bit odd. I have a thru hole cock that comes into a strainer, from the strainer there is a three with three exit valves. One goes to engine water pump, one goes to AC pump, and one goes to a hose that may be used to wash down the bilge or something... I don't know what this third one is. When I lose prime I check the strainer, nothing. I open the third valve and water flows into my bilge. I turn on pump, and it is now primed and working. ...well, now it's dead. :) I put my old one in, but it works outside the boat (spins), but not under load.
 
Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
You didn't actually say you had the hoses off in your opening post... Anywho... you can run it on the garden hose from your Marina just don't tell and only use enough pressure to go through at a moderate rate, then you can go swimming see if intake is clogged.
 
May 19, 2016
119
Catalina 30 Riverside, NJ
I ordered the SeaFlow from Amazon, it should come tomorrow. For now I have a portable AC, but it does not cool off the boat as much as the Marine AC.

The AC units, there are two, are about 2-3 feet above the pump. Each of the AC units can work independently, but a single pump feeds them both. I have only had the boat for a year, so this design is not my doing.
 
Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
My guess is you need a much larger pump but two separate pumps seem to make a lot more sense and maybe even larger through hull.. I'll do a lookup but I think you need about 250 GPH per 12,000 BTUs or whatever the units specify in this case more is better not less I don't like how these pumps heat up either I just got mine from Amazon last week it's been running since but I have a rag in the bilge wicking water up underneath the motor to help cool it off lol generally motors will run 40° C above their ambient operating conditions which means a pretty damn hot motor but as you found out they stopped working at a certain temperature and when they cool off they seem to be compromised..
 
Jun 15, 2012
628
Hunter 50 AC St. Petersburg
My boat has 3 a/c units attached to one pump, but the a/c water feed is from a separate, dedicated sea cock. A 3/4" hose runs from the sea cock to a strainer to the pump. I think you are losing prime because of the multiple connections for the a/c raw water supply.
 
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Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
Semp, would you know what size the units are and how many GPH the pump is? Thank you
 
Jun 15, 2012
628
Hunter 50 AC St. Petersburg
1020 GPH, 1 16K & 2 6K. I think the Seaflow pump you ordered will be enough flow for the 2 units you have. If one of your 2 a/c units is larger then the other, you may want to partially restrict flow to the smaller unit to balance the needs of the units. I doubt this will be necessary. My 16K unit requires 206 GPH, my 6K unit needs 64 GPH.
 
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May 19, 2016
119
Catalina 30 Riverside, NJ
My boat has 3 a/c units attached to one pump, but the a/c water feed is from a separate, dedicated sea cock. A 3/4" hose runs from the sea cock to a strainer to the pump. I think you are losing prime because of the multiple connections for the a/c raw water supply.
I have an extra sea cock near the current feed, nothing is hooked up to it; actually, I was going to install a brass 3/4 plug in it this weekend as I am not using it and don't want it opened by mistake or have it fail.

If I wanted to use the alternate seacock, I'd have to install a new strainer too I assume to keep crap out of the AC units.

However, the seacock that feeds the three mini valves on the tree only feeds one thing at a time, the AC when in slip or the engine when under power. And I don't need to run both ACs at the same time, either is enough to cool down the boat in mid summer; I think the second unit that is under my NAV table is for when at anchor and can be run through an inverter, that's what I was told when I purchased her.

water-inlet.png
 

Ward H

.
Nov 7, 2011
3,123
Catalina 30 Mk II Barnegat, NJ
@snoopy_ Here's the Amazon link to the Koolair PM500 pump recommended by Webasto for my 10,000 BTU AC unit I installed in June.
Koolair PM500
The specs show "Max Flow Rate of 8.5 GPM 31 LPM; 19-feet 4.3M of Max Head". It also has "run dry protection", whatever that is.
The Webasto spec for their 12k BTU and up units call for the PM1000 pump.

My PM500 pump always runs cool to the touch. I have a dedicated 3/4" thru hull, Groco strainer and use 3/4" hose. I won't jinx it by talking about how well it works.

Just to give you some ideas how to possibly improve the water flow,
The Webasto manual repeats several times that you must mount the strainer and pump 18" below the water line to ensure prime is not lost. (mine is more like 12")
It also warns against using too many 90 degree elbows. I'd have to go find the manual to be precise but each 90 deg elbow reduces lift by so many feet. I was able to route the pump outlet hose to use only one Groco full flow elbow. The manual also states to use a dedicated intake thru hull. It may be due to too many fittings for dual or more use reduces the incoming water flow even if the water is only used by one device at a time.

If you have a spare thru hull I would try switching to that for the AC. Installing another strainer may be cheaper than burning through pumps.

BTW, I installed this Condensate Removal Kit. It works great. Condensate is pulled out when your cooling water is flowing. No additional pump is needed and no condensate in the bilge. If I need to check the water flow I just have to look at the clear condensate line to see if the condensate is bubbling through the clear line.

Fair Winds
 
May 19, 2016
119
Catalina 30 Riverside, NJ
Ward,

Thank you, I think I like what you are saying. I ordered the other pump, but I have a portable unit on the boat so I may send the pump back and do as you say.

And where does my condensate go now? Does it lie in the tray and evaporate? Does it go to the bilge? Geesh, I'm gonna have to read my manual? They hide all the good stuff in there!
 
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Feb 26, 2009
591
Oday 30 Anchor Yacht Club, Bristol PA
Cursed! My brand new seaflo running barely two weeks locked up the night of the storm the boat was all closed up humid as a greenhouse and there I was taken apart a brand new pump to find at the armature had locked up somehow got to loosened up and spinning without the pump attached put it all back together after a few tries to start working and it's working again but very noisy so I'm sending that back I'm probably going to go to Cool Air 500 gph next!
 
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