HRO ETD (Clark Pump) locking up

[Alita]

Hello everyone.
I have been running my 12V HRO watermaker for about 6 years now. In order to reliably have water in remote places, I own two different clark pumps to swap around when one is acting up.
The old metal ETD seems more reliable, but the seals wear out quite fast.
The new plastic one - made by Sea Recovery - seems to have sturdier seals, but it has all kind of other issues.
Lately it is locking up sometimes when I start the watermaker. The water that is coming back from the membrane is just blocked dead, so my cat feed pump is building pressure way over designed limits.
Even worse: when it locks up I have to disassemble the clark pump and move the pistons inside manually to get it working again.
This happened twice now and I have no clue why it happens. When I disassemble the pump I find nothing wrong with it - other than both pistons being locked in the middle. I move one up and one down, restart it and it works... until it locks up again a few weeks later.
Anyone had a similar problem and/or knows how to fix this?

[NoTies]

If it has been some time since you last ran it and you are in calcium rich water it could be a small build up of scale in way of the piston seals stopping initial movement. This is a common problem here in the south Pacific with all our reefs. One of the reasons I like glycol for preserving them as it keeps a film of lubrication inside the pump. Is your fresh water flush working correctly?

[svlamorocha]

Originally Posted by Alita

The old metal ETD seems more reliable, but the seals wear out quite fast.
The new plastic one - made by Sea Recovery - seems to have sturdier seals, but it has all kind of other issues.

+1. The old version (shaped like a cylinder and made of metal) is much more reliable. You can also get spares or service from the actual manufacturer in Spain for a very reasonable price.

The new version (shaped like a shoebox and made out of plastic with metal ends) can be a pain until you learn how to disassemble the ETD and push both pistons to the same side with your eyes closed, then assemble it again.

The "stuck ETD" problem has two common root causes:

a) Defective ETD that was machined out of tolerance. Sea Recovery replaced many of those under warranty. Tell G r e g N e w m a n at SR that you know they shipped some defective units and you want yours replaced.

b) Air in feed water that for some reason is not bled out before the solenoid valve closes and pressure builds up. The math that drives the ETD does not work if there is air in the water. You can try replacing the solenoid valve with a manual valve and only close it after two minutes, after making sure you do not have any vacuum leaks between feed water intake thruhull and the ETD. In any event I highly recommend SR watermaker owners to carry a manual valve they can use as replacement for the Danfoss solenoid valve.

It does not help that in most (but not all) SR units the overpressure sensor is located after the ETD, hence your hoses that feed the ETD will blow up BIG time if the ETD gets stuck because the Cat pump will not stop. I believe that SR's engineers would not have passed third year at my engineering alma mater. Do not believe what the manual says, look up the sensor locations and rating and you will see what I am talking about.

Good luck

[Tellie]

Mutant Ninga Turtle "ERD" neither are a Clark pump. SR like several other manufacturers make a good watermaker line until they try to get into ERD pumps then it all goes haywire.

[svlamorocha]

Originally Posted by Tellie

Mutant Ninga Turtle "ERD" neither are a Clark pump. SR like several other manufacturers make a good watermaker line until they try to get into ERD pumps then it all goes haywire.

+1 on both statements. Spectra is the real deal.

[Alita]

Originally Posted by NoTies

If it has been some time since you last ran it and you are in calcium rich water it could be a small build up of scale in way of the piston seals stopping initial movement. This is a common problem here in the south Pacific with all our reefs. One of the reasons I like glycol for preserving them as it keeps a film of lubrication inside the pump. Is your fresh water flush working correctly?

I run it regulary and do a fresh water flush after every use and then every week, if it isn't used, which rarely happens at all.
Since I live on the boat I never used glycol before. Do you use it regulary?
There was a little caltrate build up on the metal ends of the cylinders, which I cleaned and I also cleaned the inside of the pistons after the first lock up - but the pistons do move normaly, so I don't think that's it.

[Alita]

Originally Posted by svlamorocha

+1. The old version (shaped like a cylinder and made of metal) is much more reliable. You can also get spares or service from the actual manufacturer in Spain for a very reasonable price.

The new version (shaped like a shoebox and made out of plastic with metal ends) can be a pain until you learn how to disassemble the ETD and push both pistons to the same side with your eyes closed, then assemble it again.

The "stuck ETD" problem has two common root causes:

a) Defective ETD that was machined out of tolerance. Sea Recovery replaced many of those under warranty. Tell G r e g N e w m a n at SR that you know they shipped some defective units and you want yours replaced.

b) Air in feed water that for some reason is not bled out before the solenoid valve closes and pressure builds up. The math that drives the ETD does not work if there is air in the water. You can try replacing the solenoid valve with a manual valve and only close it after two minutes, after making sure you do not have any vacuum leaks between feed water intake thruhull and the ETD. In any event I highly recommend SR watermaker owners to carry a manual valve they can use as replacement for the Danfoss solenoid valve.

It does not help that in most (but not all) SR units the overpressure sensor is located after the ETD, hence your hoses that feed the ETD will blow up BIG time if the ETD gets stuck because the Cat pump will not stop. I believe that SR's engineers would not have passed third year at my engineering alma mater. Do not believe what the manual says, look up the sensor locations and rating and you will see what I am talking about.

Good luck

I see you had some of the very the same problems.

On the first lock up one of my filter housings blew up! Ever since I watch very carefully with one finger on the stop button until the unit works smoothly.

After having had issues with two different brands of solenoid switches I did go manual valve as well.

I am fairly fast now in disassembling both ETD's. Opening the shoebox until it you can get to the pistons is very easy anyways. But who told you to push both pistons to the same side? For me pushing them to different sides seems to work better...

Could you please provide the contact info for the Spanish manufacturer of the original metal ETD?

Could you also provide the direct email of Greg Newmann? Whenever I send emails to Parker/Sea Revocery/HRO I never get an answer at all...

[GordMay]

Greetings and welcome aboard the CF, Alita.

[Alita]

Originally Posted by GordMay

Greetings and welcome aboard the CF, Alita.

Thanks. Glad to be here.

[mrdohc]

Would you kindly explain how to open up the SR shoe box ETD and reset the piston?

[svlamorocha]

Hi mrdohc
I would be happy to help if you cannot get that basic support from the the dealer or the manufacturer.

It will take me a couple of days until I get back to my home office where I have the relevant files.

Have you tried asking Sea Recovery? Where did you buy the unit? What model do you have? Have you checked if the ETD is in the serial number range that was recalled?

[Matt Johnson]

Originally Posted by Alita

Could you please provide the contact info for the Spanish manufacturer of the original metal ETD?

https://eco-sistems.com/en/ They take a day or two to responds, but you can get everything direct from them. The seals that wear are fairly standard lip seals, but it metric sizes that aren't the easiest to find online. I found it easier to just purchase then from Eco Sistems.

Matt

[svlamorocha]

Originally Posted by funjohnson

https://eco-sistems.com/en/ They take a day or two to responds, but you can get everything direct from them. The seals that wear are fairly standard lip seals, but it metric sizes that aren't the easiest to find online. I found it easier to just purchase then from Eco Sistems.

Matt

Those folks at Eco Sistems in Spain are very good. They have been very helpful over a sat phone when Sea Recovery did not care about their customers.

[mrdohc]

Originally Posted by svlamorocha

Hi mrdohc
I would be happy to help if you cannot get that basic support from the the dealer or the manufacturer.

It will take me a couple of days until I get back to my home office where I have the relevant files.

Have you tried asking Sea Recovery? Where did you buy the unit? What model do you have? Have you checked if the ETD is in the serial number range that was recalled?

@svlomorocha:
The serial # of our ETD is 015930C4513. I don't have a clue where to find whether this is a recall unit or not. It came with the boat, factory installed: Lagoon39. 2016 model. The SR model is Ultra Whisper 400.
Currently we are in SXM, have the local SR technician came by and check the unit but unfortunately he doesn't know what was going on. Expect to hear from him after he talked to the SR factory but no news from him yet. We are leaving the island soon and move on so hopefully be able to find someone who can help, either here or somewhere else like Curacao... Or be able to fix the problem myself.

[svlamorocha]

SR can tell you if the ETD is eligible for recall. I wish you luck with SR "technicians" I have sailed from Buenos Aires to the Caribbean more than once on boats with SR watermakers and spent too much time waiting for those techs to show up and fix those things under warranty until the owner got fed up and I had to show the "tech" how to take the thing apart and make it work.