At 09:00 PM 6/21/2009, Phil McGovern wrote: >OK, maybe this will start a discussion: Sunshine came with a PUR 35 >(now Katadyn) powered water maker. I'm guessing the watermaker is >about 10 years old and I'd like to resurrect it if possible. I know >very little about its history but I did run it a couple of times as >a test while we were on the boat. The pump pumps and water comes >out, but the pump leaks a little (I think new seals should fix that) >and the water tasted OK to me but it tested off the scale. Our >little Walmart water tester showed 999 parts per million and >blinking, so my co-captain is not happy with the output.
First, it takes about five minutes to get "pure" water from a watermaker. If it was pickled (biocide treatment), and hopefully it was, it has to run at least 20 minutes before good water is produced. Correct on replacing the seals to fix the leaks. Testing the membrane. To test for clogging, make water into a large measuring cup and time it. I think the 35 is 1.2 GPH. So if you run it for 20 minutes and you should get 51.2 fluid oz. Note that cold water will cut this down a bit, less than sea water will produce a little more. If, after running long enough to clear out biocide, etc., the water tests good, the membrane is not cracked. If in fact the membrane is okay, I'd recommend getting the cleaning and biocide chemicals. I'd do both cleanings. If the output was low this should fix it up. Even if the output was okay, it wouldn't hurt to clean. Pickling. Note that the watermaker should be run daily. You can go for about 3 days in warm waters, 5 in cold water. If it's going to be idle for longer it really needs to be pickled. A good idea is to run some product water into a container, then run it though just before shutdown. This cuts down on bacteria growth. If not in clean offshore seawater, pick up another pre-filter from Home Depot and add it in with a 5 micron filter. The one that looks like it's made from wound string. Then you can make water pretty much anywhere, but the siltier the water, the more often you have to clean the pre-filters. About 30-bucks as compared to the $300 or so "Silty Water Kit". >I took the watermaker off the boat and brought it home, thinking I >would replace the seals and see about the membrane. I then >discovered that it is a 24 volt model and had been installed on a 12 >volt boat. Don't ask me why. From extensive experience with DC motors... The motor will run hotter at 12V, so that's probably why the tech said it won't last. DC motors really don't have a set voltage rating, but the lower the voltage the higher the losses and the higher the current for the same power output. At 12V the volume output of the pump should be less, but the current should be higher because it's the same load to get that 800 PSI. There are several ways to get 24V from 12V. Probably the easiest and cheapest is to just get an extra low cost battery and series it with your house bank for the watermaker. Like some folks do with a bow thruster. You can rig it with a DPDT (Double Pole Double Throw) switch to parallel it with your house bank to recharge when not in use. Email me direct if you need details. There are 12V to 24V DC to DC converters. Most are for commercial equipment and are expen$ive. I had a PUR 40 and recall it drew about 4.5A at 12V, so probably 2.25 to 2.5A at 24V, so I'd say you need one that's rated at least 4A to be safe. If you have an inverter, you may find a 24V power supply. Our build one with a 24V transformer and bridge rectifier. The problem with this is you're going to waste power with the inverter and power supply losses. You could also pick up 2 of the cheapest 6A battery chargers you can find and connect the outputs in series. Yes, this works. Bottom line though is the extra battery and "charging" switch is really the simplest, cheapest and most efficient solution. Another option is to rewind the motor. I used to do this a bunch ages ago, but I no longer have the equations. Maybe you could find a sharp electric motor shop that could do it. Feel free to email me direct if you have any questions or need a bit of help. Rick 'n' Cathy S/V Valkyrie http://www.morelr.com/valkyrie _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://www.liveaboardnow.org/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardnow.org/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
