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Old 12-05-2019, 04:00   #1
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Spectra 150T Troubleshooting Low LPH

Hi Cruisers, any guidance that could be provided on this issue would be very appreciated. My Spectra 150T system is behaving as follows:

Hour 1
LPH starts at 27 and gradually comes down to 20
Feed Pressure 4.1

Hour 2
LPH starts around 20 and comes down to around 15. Show some instability in that the figure jumps around periodically.
Feed Pressure jumping about slowly from 4.1 to 4.6

Hour 3
LPH starts around 15 and comes down to around 12. Shows more instability in that it will jump from one to the other regularly.
Feed Pressure jumping from 4.1 to 4.6 more frequently
MPC5000 reports prefilter alarm - despite prefilter being clean. Restarting the system later will make this alarm go away until about the third hour again.

I have noted that at hour 3 the analogue pressure gauge shows what looks to be the clark pump shifting asymmetrically. On one stroke the pressure is 50PSI and rises to 60PSI before shifting. On the other stroke the pressure remains at 50PSI and there is a small spike as the pump shifts.

I am unable to identify any unusual noises from within the pump on either shift (can this rule out the annular rings?).

I have opened the test port and there is what appears to be more than 2 drips an hour but nothing substantial coming out (can this rule out the piston seals?)

Battery voltage remains good (12.8+) throughout tests.

I am at a bit of a loss as to where too next. In Australia I can have this pump rebuilt at considerable cost >$1500 AUD. Or do I pull it down and see what I can find - perhaps one of the pistons or cylinders is obviously shot?

The MPC reports the unit has >3000 hours. Not sure if this counts when it has been left doing fresh water flushes, or that is 3000 hard hours making water?

I am currently trying to avoid running the unit and making for a marina where I can pull it down or ship it back to the Spectra distributor in Australia.

Unit is circa 2006.

Cheers!
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Old 12-05-2019, 11:36   #2
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Re: Spectra 150T Troubleshooting Low LPH

My first impression is that your membrane might need a cleaning cycle.
I have a Spectra 180 upgraded to a 200. Strictly a manual model.
Tellie should be along shortly. Listen to him.
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Old 12-05-2019, 20:04   #3
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Re: Spectra 150T Troubleshooting Low LPH

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Originally Posted by senormechanico View Post
My first impression is that your membrane might need a cleaning cycle.
I have a Spectra 180 upgraded to a 200. Strictly a manual model.
Tellie should be along shortly. Listen to him.
Thank you for considering the problem and responding. It is certainly a possibility, however even with the low output we are seeing 400-500ppm (confirmed with handheld tester) which i believe suggests the membrane is in reasonable condition.

Today i have blocked the brine discharge line to test the low pressure pump, pressure rose to 125psi and shut off. So i guess this can be ruled out.
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Old 13-05-2019, 10:23   #4
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Re: Spectra 150T Troubleshooting Low LPH

Imho, 4-500 ppm is too high.
I manually shift mine to saving water at around 225 ppm which usually takes around 4-5 minutes to achieve.
After it's been making water for an hour, the ppm goes down to around 90 to 130.
This is in the PNW with water temps between 45 and 70 degrees f. Salinity will vary considerably depending on location as well due to snow melt.



Where are you using the Spectra? Salinity as well as water temperature will cause differences in PPM and LPH.
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Old 14-05-2019, 05:04   #5
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Re: Spectra 150T Troubleshooting Low LPH

Your problem is definitely in the Clark pump. Your pressures are good from the feed pump, and 400-500ppms with a asymmetrical Clark pump are to be expected. The ppm readings will get better once you resolve the Clark pump issues. Has the pump ever been rebuilt? If not, I would assume that both your check valve O-rings and your annular ring O-rings are shot and need replacement. But it is probably time to pull the pump and dissemble it and at least visually examine the interior parts for wear.



I have noted that at hour 3 the analogue pressure gauge shows what looks to be the clark pump shifting asymmetrically. On one stroke the pressure is 50PSI and rises to 60PSI before shifting. On the other stroke the pressure remains at 50PSI and there is a small spike as the pump shifts. This is your biggest issue.

I am unable to identify any unusual noises from within the pump on either shift (can this rule out the annular rings?). No, but if your pump has never been worked on I would highly suspect the annular ring O-rings are shot.

I have opened the test port and there is what appears to be more than 2 drips an hour but nothing substantial coming out (can this rule out the piston seals?) Yes, it is normal to see a small amount of dripping from the test port indicating that the rod seals are in good condition. Streaming water from the test port would be bad seals.

Battery voltage remains good (12.8+) throughout tests. Good.

I am at a bit of a loss as to where too next. In Australia I can have this pump rebuilt at considerable cost >$1500 AUD. Or do I pull it down and see what I can find - perhaps one of the pistons or cylinders is obviously shot? Tear it down yourself first. Send me detail pictures of all the parts.

The MPC reports the unit has >3000 hours. Not sure if this counts when it has been left doing fresh water flushes, or that is 3000 hard hours making water? 3000 hrs of water making.
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Old 14-05-2019, 05:33   #6
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Re: Spectra 150T Troubleshooting Low LPH

Thank you Tellie, sounds like a good plan. We have arrived into a marina this evening and i will tear the pump down tomorrow.
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Old 14-05-2019, 06:05   #7
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Re: Spectra 150T Troubleshooting Low LPH

Great, send detailed pics of the parts you dissemble. I'm particularly interested in the two check valve O-rings as to whether they are white or black. If they are white then they, along with the annular ring O-rings, must be changed out. The two check valve O-rings are located at the cylinder base, You can't miss them when you remove the cylinder. Also I want to see the inside of the cylinders. Use a wooden hammer handle or such to push the pistons all the way down the cylinder. Dry the interior well, check for scoring and send a pic. The more pics the better.
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Old 15-05-2019, 02:34   #8
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Re: Spectra 150T Troubleshooting Low LPH

Thank you Tellie - I have sent you an email with the photos.

I will summarise what I found here for the future sake of anyone else going through this learning experience.

Annular Rings are white - however there is no cracking, pitting or otherwise present. The spool assembly is a tight fit in both directions. Should these still be replaced anyway given they are made from the faulty material?

Check Valve Seals are black - I previously replaced these on your advice in 2017 when the pump had a major leak between the blocks.

The check valves were free of debris and appear to operate and seat okay. When i line all four up next to each other I can see two rise a little less than the others - the plastic spring washer seems to be more depressed. Is this a problem?

Both cylinders show some minor wear marks. One cylinder has a reasonable score running part way around the cylinder, about 20mm is deep enough to feel a ridge with your finger nail. I suspect this might be enough of a score to have caused the piston seal some problems? Unfortunately despite multiple attempts both with a strap wrench and a hammer and screwdriver (sorry) it has not budged. Is there any secret to getting these off without the right tool? What do I do about the scored cylinder once I find a way to get the end off?

The other peculiar observation I have made given the asymmetry, is that one side of the piston rod looks nice, the other side has white marks running along it....?

I would attach photos here but it seem even in 2019 you need external hosting. If anyone wants to see the photos I can send them to you.
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Old 15-05-2019, 03:33   #9
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Re: Spectra 150T Troubleshooting Low LPH

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Old 15-05-2019, 13:58   #10
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Re: Spectra 150T Troubleshooting Low LPH

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