Spectra Ventura 150 issue with pressure

[Mirador]

Just got my Spectra Ventura 150 going on a boat that is new to me. Previous owner was pretty fastidious. Unbelievable number of spares for unit. I changed the filters on both the Prefilter and Charcoal freshwater filter. I took the seastrainer apart and cleaned it. All were in good shape, with the old filters not too smelly and water pretty clear. I ran the brine side into a bucket before flushing and examined it. It was remarkably clear and only slightly smelly. I took that to mean that the membrane was in good shape. I then flushed the system with fresh water (don't know why) and then sea water. I ran sea water thru with the pressure release valve on the Clark filter open a crack for about 20 minutes. I then closed the pressure release valve. The pressure rose to about 60 PSI and then made a gushing sound and pressure dropped to about 30 and gradually rose again to 60 where the cycle repeated every few seconds. I could see bubbles in the flow meter and figured there was air in the system, so I opened the pressure release valve on the Clark pump again to purge. When I closed the valve, the same thing happened. I tried multiple times to purge the air, but each time the same cycle would start again. It did make fresh water, which tested to 175 ppm. The water tasted ok, but had a slight smell to it, which I attribute to being in a river with extensive mud flats and marshes with a similar smell.

Anybody have any ideas? Is this normal operation? I think not. But at least it is making fresh water.

[Tellie]

Hi Mirador, Here are a few things to consider. First when you purge the storage solution (pickling compound) the pressure relief valve on the Clark pump should be opened about 1/2 to 3/4 of a turn, not just a crack. The brine discharge won't tell you much of anything about the condition of the membrane, pressures, flow, and TDS readings will give you a more accurate idea of what's happening with the membrane. The Ventura 150s pressure gauge reads the feed pump pressures. 60psi is a good reading depending on the surrounding water that you are in. It is quite normal for the pressure to spike to 60psi then drop off as the Clark pump shifts to it's second stroke. This usually takes about 5-7 seconds. Also the flow meter should be reading about 6.5 gallons per hour when the pressure is up to 60psi. When a Spectra has been sitting for a long period of time in the pickled sate it is not unusual at all for air to get into the membrane and when you pressurize the system you can see bubbles in the flow meter for several minutes. Just let the system run normally under pressure and the bubbles will eventually subside. The 175ppms is a good number normally but you state you are in a river. Most rivers of course are fed with fresh water so this number can be deceiving if you don't know the ppms of the water you are in, but the pressures seem to indicate that the water is salty. Test the system off shore a bit and let me know the ppms. The slight smell is normal after a system has been sitting for so long. Running the system for a few hours should lessen and eventually eliminate the odor. Most of these odors comes from the pre-filters. At first glance of your post I'd say that your 150 is probably acting normally and in fairly good shape. Feel free to ask me any questions you might have on your unit. There's a small learning curve but once you learn it you'll be on your way.

[Mirador]

Thanks so much for your reply. Very helpful.

[Mirador]

One more question. I ran the watermaker initially to make sure it worked, since the boat was new to me. Now that the Spectra is 'in commission' I have decided to flush with fresh water every 5 days to keep the bugs from growing (not running the watermaker for actual reverse osmosis work). I am currently in SC in the ICW, working my way to FL. In FL, I will go outside to the Lauderdale area (I can use the water maker outside), and then cross to the Bahamas shortly after, where I plan on using the water maker.

#1: Is this silly (flushing every 5 days), as opposed to pickling for the next 3 weeks? If figure I'll actually waste less water in the long run, as a flush from pickling is 20 min, vs, 2.5 min from fresh water flush to fresh water flush. Five flushes would be less water than one 20 min post pickling flush.

#2: If I do continue to go from fresh water flush to fresh water flush, is there any need to throw away the water that comes across the membrane? It seems to me that I could run the water back into my tank directly and save the water. The only issue I could see is if there were growth starting, it could inoculate the tank. I also find it odd that the manual doesn't mention whether you leave the pressure valve open or shut when flushing. I am assuming that you leave it shut, as this should actually wash through the membrane.

[Windara]

The pressure relif valve should be closed when doing a fresh water flush.

Yes, you will get product water of about 10% to 15% from the fresh water you use to do the flush, but the rest goes out the brine hose.

Everytime you pickle you stress the membrane a little, so if you have access to surplus fresh water, I would flush every 5 days rather than pickle for such a short time.

I would not run the watermaker to make water while in the ICW as there is a fair amount of silt in the water that can hurt the pumps.

Fresh water flush only uses about 3 to 5 gallons, depending on how long you run it.

I've had a Catalina 300 for 5 years and had excellent results. Clean your filters often. I tow them on a poly line with a big knot in the end while sailing offshore , and they clean up very nicely. Have cleaned filters 10 times before needing to be replaced. Only exception is charcoal filter, that cannot be cleaned, but that is usually good for 6 months as it just declorinates the fresh water used for flushing.

[Tellie]

Originally Posted by Mirador

One more question. I ran the watermaker initially to make sure it worked, since the boat was new to me. Now that the Spectra is 'in commission' I have decided to flush with fresh water every 5 days to keep the bugs from growing (not running the watermaker for actual reverse osmosis work). I am currently in SC in the ICW, working my way to FL. In FL, I will go outside to the Lauderdale area (I can use the water maker outside), and then cross to the Bahamas shortly after, where I plan on using the water maker.

#1: Is this silly (flushing every 5 days), as opposed to pickling for the next 3 weeks? If figure I'll actually waste less water in the long run, as a flush from pickling is 20 min, vs, 2.5 min from fresh water flush to fresh water flush. Five flushes would be less water than one 20 min post pickling flush.

#2: If I do continue to go from fresh water flush to fresh water flush, is there any need to throw away the water that comes across the membrane? It seems to me that I could run the water back into my tank directly and save the water. The only issue I could see is if there were growth starting, it could inoculate the tank. I also find it odd that the manual doesn't mention whether you leave the pressure valve open or shut when flushing. I am assuming that you leave it shut, as this should actually wash through the membrane.

Just keep flushing it every five days. Don't pickle it for just three weeks if you're going to be on-board.

I only do this for CF members, but if you're going to be in the Ft.Lauderdale area, I'll come by your boat and go over your watermaker with you and explain to you thoroughly it's operation and care if you like, no charge.
Well, maybe a beer.