ac pump

[xluke]

Hello,
I am working on a semi-permanent ac system for my boat. Any reason I can't use a submersible bilge pump (rated 500-1000GPH) as a pump for a water cooled ac system?
The systems call for about 250-500GPH water pump, the only thing I am questioning is whether a bilge pump is up to the challenge of running a few hours constantly...

Thanks!

[Zanshin]

Most of those pumps are cheaper for a reason - they aren't designed to run continuously and their rated output is only ever acheived when there is no head on the output, i.e. no restrictions in flow and no vertical component. Once backpressure is present, their flow drops way down.

[deniseO30]

Do you mean to use a bilge pump to pump Through the heat exchanger? That would be a no, you need a pump that has what is called "head" meaning it has a impeller designed to push water against a given amount of resistance. Also the motor would not be able to run continuous.

[PorFin]

Um, yeah, not the best idea.

First, like mentioned above, a bilge pump's not designed for continuous duty.

Second (and in my book a bigger downside), if your a/c system is typical, it's a 110vac system. You're going to be plugged in to a 110v source (shore/gen) anyway to run the a/c compressor and the blower, so adding a power drain on your 12v system will leave you running your battery charger anyway. There's going to be losses due to inefficiencies, and you'll be making unneccessary demands on your batteries and charging system. This could well wind up as one of those instances where that nickle you save winds up costing you dollars in the long run.

A decent 110v continuous duty pump is not hard to find.

[svHyLyte]

You need an air-cooled continuous service pump. The most reliable pumps for on-board A/C units are March pumps--see Marine Catalog 110 from Depco Pump, one of the least costly sources.

FWIW...