Neptune DOS Modification

[WireTech]

I really like the DOS pumps but wasn't thrilled with the tubing connections. I found that the threaded connection was 1/8" NPT therefore it was just a simple part exchange. The conical grey part of the fitting on the pump can be removed with a razor. I tried both ways and saw no difference in the push fittings ability to seal. (note: tubing does push in further if removed). Tubing removed from pump for photo. Modification can be done without dis-assembly.

[Member No. 1]

Sweet!
I hate the so called "Flex" tubing that Neptune supplies. That stuff has a mind of it's own!

[WireTech]

Originally Posted by Member No. 1

Sweet!
I hate the so called "Flex" tubing that Neptune supplies. That stuff has a mind of it's own!

The tubing they supply was my main reason for this modification. If push-to-connect is good for the DDR why not the DOS.

[Kaidman]

I may have to give this a shot. I was planning to do a john guest union just a few inches off the DOS. This is even cleaner. Thanks for sharing!

[acesq]

so what are you using for tubing with this mod? RO tubing?

[805reef]

Nice! Looks clean. I use ro tubing and just heat it up a bit and push it up on the nipple.

[slief]

Originally Posted by acesq

so what are you using for tubing with this mod? RO tubing?

He's using the stock tubing. This is actually a pretty interesting mod. I use 1/4" RODI type tubing & while I have no issues with the existing fittings, I much prefer the John Guest style push lock fittings & have everything I need for this mod. I might just have to do this myself.

[WireTech]

Originally Posted by Kaidman

I may have to give this a shot. I was planning to do a john guest union just a few inches off the DOS. This is even cleaner. Thanks for sharing!

I did that and decided there must be a better way. Glad it helps out.

[acesq]

Scott, I set up an auto feeder with my DOS using your wine cooler design and the Neptune stock tubing. I'm worried that if I do this mod and use the RO tubing (which is necessary for an airtight fit with the JG fitting, right?), the smaller i.d. of the RO will more easily clog. Am I right?

As an aside, my wine cooler fried from excess condensate getting into the motor when I used it on a four day trip. Has this happened to you?

[WireTech]

Originally Posted by acesq

so what are you using for tubing with this mod? RO tubing?

Yes I'm using RO tubing. Should have included that in my post. It comes in different colors that helps keep things organized.

[slief]

Originally Posted by acesq

Scott, I set up an auto feeder with my DOS using your wine cooler design and the Neptune stock tubing. I'm worried that if I do this mod and use the RO tubing (which is necessary for an airtight fit with the JG fitting, right?), the smaller i.d. of the RO will more easily clog. Am I right?

As an aside, my wine cooler fried from excess condensate getting into the motor when I used it on a four day trip. Has this happened to you?

That's an intresting point. The barbed fitting is indeed a smaller diameter as far as I am aware. I will have to take a look. I have a set adapters with the 1/8" barbed fittings to JG fittings and a spare set of Dos heads with tubing. I will compare the sizes but I do think you are right and it could pose an issues with mysis clogging the fittings.
I haven't had a condensation issue with mine and mine has been running 24/7 for several months now. What cooler are you using and have you figured out where the condensation was originating from? If it's coming from the area where the bottle sits, try sealing any seams with silicone or some sort of spray in plastic coating to seal it in.

[slief]

Originally Posted by acesq

Scott, I set up an auto feeder with my DOS using your wine cooler design and the Neptune stock tubing. I'm worried that if I do this mod and use the RO tubing (which is necessary for an airtight fit with the JG fitting, right?), the smaller i.d. of the RO will more easily clog. Am I right?

After looking again at the pictures above, he's using the Neptune fittings and just threading the JG adapters over them. As such, there would be no issues with clogging. I need to go back and check to see if I have the right JG's because if I do, this mod is a simple and great idea. If I don't have them, I will go by Do It Center and see if they have the correct Watts 1/4" Push Lock fittings that will thread onto the Neptune Dos ones. One suggestion for anybody that does this mod. Use teflon paste on the threads and not teflon tape. That way you get a good seal.

[WireTech]

Originally Posted by slief

One suggestion for anybody that does this mod. Use teflon paste on the threads and not teflon tape. That way you get a good seal.

I found that sealant was not necessary. I put the fittings on hand tight and have no leakage. There's not much pressure developed.

[slief]

Originally Posted by WireTech

I found that sealant was not necessary. I put the fittings on hand tight and have no leakage. There's not much pressure developed.

Good to know. I'd probably err on the side of caution just to be safe but it's good to know you probably don't need it. Either way, it's a great idea for those of us using 1/4" RODI style tubing and a very simple mod.

[hkgar]

I did the modification yesterdays. My DOS is used for AWC and I had leak on the side drawing water from the storage reservoir and had to use Teflon tape in order to get it to pump the water up. I am also getting periodic small air bubbles on the outlet side of both pumps but I am using the DOS supplied tubing on the discharge side and RO tubing on the inlet side.

[WireTech]

Originally Posted by hkgar

I did the modification yesterdays. My DOS is used for AWC and I had leak on the side drawing water from the storage reservoir and had to use Teflon tape in order to get it to pump the water up. I am also getting periodic small air bubbles on the outlet side of both pumps but I am using the DOS supplied tubing on the discharge side and RO tubing on the inlet side.

Sorry to hear about your troubles. To date I have had no leaks and I did not use any sealant. My top DOS in the picture is also used for AWC. The point of this modification was to do away with the DOS supplied tubing and ease of tubing connection. The push connect fittings are made for RO style tubing. I have however used them on silicone air line with no leaks. Did you use the same type fittings that I pictured? I cannot speak for any other style if used. Is the fitting hand tight? Mine are nearly touching the orange housing. If you are getting leaks in or out and tubing is fully inserted I would suggest using a razor blade to remove the conical portion of the DOS fittings. This allows greater tubing insertion. See the right end of tubing in original pictures. Hope this helps.

[eb2292]

Did you have to recalibrate your DOS after changing the tubing?

[slief]

Originally Posted by eb2292

Did you have to recalibrate your DOS after changing the tubing?

It is always a good idea to recalibrate after tubing changes. Friction loss due to tubing material differences and lengths will impact flow rates if even slightly. As such, recalibrating is a good idea to insure your fluid transfer amounts are as accurate as possible.

[Aero175]

Where did you order these connectors? I am having a hard time finding the right ones.

Thanks

[hkgar]

US Plastics

[Aero175]

Thank you!

[slief]

Originally Posted by Aero175

Where did you order these connectors? I am having a hard time finding the right ones.

Thanks

I got mine from a different online supplier in qty 1 increments instead of the larger pack that US Plastics sells. I will look for that supplier.

That said, I had to cut the tops off the Dos tube ends because they interfered with the 1/4" tubing and prevented it from going all the way into the JG fitting. Not a big deal and I just nipped the tips off with a scissor which allowed the JG fitting to thread all the way on. I also used Teflon paste to insure there was never going to be any leaks.

[slief]

Here is where I got mine.
https://www.freshwatersystems.com/p-...x-18-nptf.aspx

[Aero175]

Thank you, I will check them out as well.

[WireTech]

Originally Posted by Aero175

Where did you order these connectors? I am having a hard time finding the right ones.

Thanks

Sorry I didn't get back to you sooner (currently in Brazil on vacation) but as always there are others that have the answers. I can't remember exactly where I got them but a online search for the brand and/or part number should get you what you need. I was able to order the quantity (8) that I needed. Did not have to order a full bag as others have indicated. Hope this helps.

Greg