Spectra Newport running too well?

[Anjin]

This is my second season of cruising with my Spectra Newport and I'm seeing some performance issues that are baffling me. All last season it ran according to specs - Product Output - 16+ GPH, Salinity < 100PPM, Feed Water Pressure between 100 and 110, Prefilter Flow ~17 with new filters dropping over time to ~12 when time to replace. My only complaint was that my attempts to clean and reuse filters were not very successful.

For this season I bought enough filters to allow changing every week without reuse. I used Flow-Max brand 5 micron and 20 micron pleated poly filters. Now that I've started using them I get all the same numbers on Salinity, Feed Water Pressure, and Prefilter Flow, but the Product Output is only 13 to 13.8. On the other hand, the new Prefilter never seems to clog - I put in one set of new filters at the start of the season and they are still reading 17.42 - same as new - after producing about 800 - 1000 gallons.

I ran a total flow test and came out close to 2.8GPM but did not separate the product from the brine. But the 13+ GPH product rate seems accurate in terms of how long it takes to fill my tanks.

But I don't get why the filters are still not showing any clogging and what that has to do with the reduced product flow. Any one out there have any similar experience?

Thanks in advance!

[Tellie]

Give me a call when you get a chance and we'll talk.

Best Regards
J.T. Halden (aka Tellie)
(954) 515-7077

[Nightsky]

2 separate issues at play. The membrane will lose efficiency with time so production will drop year over year. As to the filters, it may just be that you are in clean, plankton-free water so there is very little in the seawater to clog the filters.

[Anjin]

I took Tillie up on his very generous offer and spoke with him.
He believes that I may have some calibration/installation issues that are causing these symptoms and has laid out a testing approach to help confirm this and correct the readings I'm getting.

Originally Posted by Nightsky

2 separate issues at play. The membrane will lose efficiency with time so production will drop year over year.

Thanks Nightsky. As I said, this is only the second season so if it turns out to be a membrane problem it is probably from operator error (i.e. my mistake). The testing should help isolate this.

Originally Posted by Nightsky

As to the filters, it may just be that you are in clean, plankton-free water so there is very little in the seawater to clog the filters.

That would be a terrific answer. I'm just skeptical since it is the same cruising grounds as last year. Hopefully the testing will help isolate this as well.

Thanks again to both of you!

[CarlF]

While this doesn't sound like your problem - I saw similar product water changes going from 80 degree Bahamas water to 50 degree Maine waters.

[Anjin]

Originally Posted by CarlF

While this doesn't sound like your problem - I saw similar product water changes going from 80 degree Bahamas water to 50 degree Maine waters.

Well the water is colder here (northern bahamas) than last year (south central bahamas) but probably only about 5 degrees, not enough to account for the differences I'm seeing. Thanks for replying!

[Lambretta]

Originally Posted by Anjin

Well the water is colder here (northern bahamas) than last year (south central bahamas) but probably only about 5 degrees, not enough to account for the differences I'm seeing. Thanks for replying!

Hi there

Please post the results of your tests and what the problem(s) and the solution(s) are ........... hopefully you have got to the bottom of the matter
Thanks

[Anjin]

Originally Posted by Lambretta

Please post the results of your tests and what the problem(s) and the solution(s) are; hopefully you have got to the bottom of the matter

Ran a total flow test and a product flow test carefully timing and measuring at each step. The product flow was 12.5 GPH vs 13.5 indicated vs 16.7 expected. The total flow was 2.81 GPM, almost exactly to spec. So it doesn't seem to be a boost pump or feed pump problem. According to my debug manual, could indicate a problem on the high side of the clark pump. From the literature I've seen it does not indicate a membrane problem, but my gut is telling me not to rule that out. All other readings are nominal - salinity<100ppm, pressure 106, prefilter flow 17.29 (blank graph indicating good rather than replace).

So, no, haven't gotten to the bottom of it yet. Not a crisis yet, just running it longer than normal. Will update as I work through it.

[Tellie]

Originally Posted by Anjin

Ran a total flow test and a product flow test carefully timing and measuring at each step. The product flow was 12.5 GPH vs 13.5 indicated vs 16.7 expected. The total flow was 2.81 GPM, almost exactly to spec. So it doesn't seem to be a boost pump or feed pump problem. According to my debug manual, could indicate a problem on the high side of the clark pump. From the literature I've seen it does not indicate a membrane problem, but my gut is telling me not to rule that out. All other readings are nominal - salinity<100ppm, pressure 106, prefilter flow 17.29 (blank graph indicating good rather than replace).

So, no, haven't gotten to the bottom of it yet. Not a crisis yet, just running it longer than normal. Will update as I work through it.

If your membrane is reading less than 100PPMs(use a hand held TDS meter to verify), pressure 106, and production is 13.5, then the problem is in the Clark pump. If you added a 0-200psi pressure gauge in between the feed pump out put and the Clark pump input I'm willing to bet you'll find your problem. Perhaps a worn out cylinder, a stuck check valve, or just a tired Clark pump that may need to be looked at and freshened up.

[Anjin]

TDS meter was ordered but since I'm in the Bahamas (where nothing gets delivered in less than a month) I had it sent to a friend who will be arriving next week. While I'm waiting, will start running some of the tests outlined in the Spectra Troubleshooting Guide section 6 - Clark Pump Checkout. Thanks!

[peter57]

Very interesting, listening. Thanks for posting.

[Anjin]

So, still waiting for TDS meters to arrive and have been too busy to run other tests, but the numbers are starting to change and I thought it worth reporting.

Product flow now indicating higher, starting the run at 15.2+ and finishing at 14.5 or so. Feed Water Pressure has risen slightly from 105 to 110, Prefilter Flow has dropped slightly to just under 17 (still a clean bar graph indicating keep rather than replace) and Salinity still indicating < 100PPM.

I started this thread because I was concerned that my pre-filters weren't clogging and because the product flow was too low; I was wondering if there was a correlation or connection between the two. Now the pre-filters are starting to show some resistance and the product flow is rising as is the Feed Pressure. All changes are relatively small but statistically significant.

Still baffled but will test salinity with 2 new TDS meters this coming week and also find the time to do the clark pump tests.

[Anjin]

TDS meters arrived. Tested sample at the tap rather than the product fill line. All water in the system has been generated by the watermaker - no tap or dock water. Sample tested at 84PPM on one meter and 87PPM on the other. System reporting "<100PPM".

So product quality seems fine, product output has been varying with some runs up at 15+ gph and others as low as 13+ gph. Pressure seems to vary and is correlated to product flow - pressures of 113 = product flow of 15+ while pressures of 106 = product flow of 13+. Prefilter flow is starting to degrade (finally! these filters have been in for a month) but is still around 16 and the bar graph is still showing "good".

[Tellie]

Originally Posted by Anjin

TDS meters arrived. Tested sample at the tap rather than the product fill line. All water in the system has been generated by the watermaker - no tap or dock water. Sample tested at 84PPM on one meter and 87PPM on the other. System reporting "<100PPM".

So product quality seems fine, product output has been varying with some runs up at 15+ gph and others as low as 13+ gph. Pressure seems to vary and is correlated to product flow - pressures of 113 = product flow of 15+ while pressures of 106 = product flow of 13+. Prefilter flow is starting to degrade (finally! these filters have been in for a month) but is still around 16 and the bar graph is still showing "good".

Check your voltage when the production is high and when it is low.

[Anjin]

Originally Posted by Tellie

Check your voltage when the production is high and when it is low.

I've accumulated a lot of data and there is a slight correlation to voltage and production. over a fairly large number of runs, 12.5-12.8 volts typically yields 13.3 to 13.8 GPH, 13 volts (when the generator is running) yields about 14.1 to 14.2 GPH. I get sporadically higher readings especially at the start of a run and product quality is always right around 100PPM.

Looks like it will get me through the season and I will do more serious diagnostics and repair when I'm back in civilization.

Thanks for all your help and advice!!

- Art