T&T: AC raw water pump flow rate?

[Milt Baker]

Keith,

If your water flow is barely adequate, your air conditioning lines may need need backflushing.  It's not a fun job, but you can usually find an AC service tech to take care of it for you.  If you have to do it yourself, you'll need a good pump, some dilute muriatic acid, and the time and patience to backflush each hose and component in your AC system.  Keeping the raw water lines clean is especially important if you're in a high fouling area with very warm salt water where they tend to foul more rapidly.  If it's been years since your system was cleaned, you'll be surprised how mucch "stuff" comes out when the system is backflushed!  And how much more water is passed after you've done the job.  

One excellent and trustworthy source of information on pumps, including capacity vis-a-vis BTUs, is Depco Pump Company in Florida (727-446-1656). I recently replaced my single AC pump (60,000 BTU air conditioning system) with two pumps so I could split the five compressor units and reduce power consumption.  I also needed to consider how the replacement pumps would perform on 50 hz. since we are taking the boat to the Mediterranean this summer.  George at Depco had all the information I needed and sold me two March pumps at a decent discount as well.  This company SPECIALIZES in marine pumps and knows it all.  No connection, just a happy customer.

--Milt Baker, Nordhavn 47 Bluewater




Keith wrote: 

Well, my AC raw water pump went out. It's a March AC-5C-MD, rated at 16.5 
GPM. The water flow has always been adequate, barely. I was wondering if I 
could upgrade to their 5.5 series, which is a 30 GPM flowrate, without 
blowing my water circuit all to hell? The pump has a 1"  input and 1/2" 
output. The output is split to two air conditioners, each with 1/2" tubing.