Yamada NDP-15 pump issues

[SteveC]

  Hello all,  I have been having what I hope is a small issue with my pump recently.  My Yamada NDP-15 FVS has been flowing more air than normal out of the exhaust with the spray nozzle closed (deadheaded??) making my compressor cycle repeatedly.  It doesn't happen all of the time, but it will happen a few times per job.  If I turn off the air to the pump and then give the pump a few taps with my palm it will most of the time correct it.  This obviously is not the way I want to continue to run the pump.  I have checked the whole system for any other air leaks and I didn't find any.  There is a screen at the end the down tube and I have a Tsunami 1/2" water separator. I probably only have about 40 hours on the pump and I flush it with fresh water after every use.  I was hoping that someone else may have experienced this and it is an easy fix.  Any input would be greatly appreciated.  

[Shingle Brite]

Is that a new pump? My guess is you need to rebuild the air end and it's just a matter of time before it quits completely. 

[SteveC]

Yes its new.  I called Yamada and talked to a tech and he was saying a rebuild.  WTF.  I have never gone over 75 psi and thought that I have been doing the right thing with it.  Thanks for your opinion. 

[garyw]

try putting several drops of light oil into the air intake.

[SteveC]

Thanks Gary, I will give it a try. 

[PeakOfPerfection]

It isn't unusual for an AODD pump to dump a bit of excess air from the exhaust when deadheaded. Question is...how much air is coming out? If it is a LOT, then an air end seal is bad. If only a small amount, then that is just a bit of seal bypass. I've had more issues with air ends on the 1/2" Yamadas than nearly any other pump. Think it is the way they do their air end. Honestly, the entire 1/2" pump design is a bit weird. Works okay, but weird. One thing on those pumps is that they REALLY want dry air, so your airline moisture management is critical. Read the stickied article I wrote in the Premium members section on air line moisture management for AODD pump systems. The Yamada and the All Flo seem to be the most sensitive to it (the ARO, big Sandpiper, Price and FloJet pumps seem to be a lot more forgiving). 

[Jim Ordway]

I just replaced diaphram's and seals on my NDP-15.  When I hooked it back up it wouldn't pump, so I disassembled and redid it...still no flow (light spurts).  Massive air coming out of the exhaust port.  Could this be an issue with the air side and need to be rebuilt?

When the diaphram went out I had liquid coming out the air exhaust port.  This is when I gave Kevin a call, he highly recommend I disassemble and get it rinsed out well, which I did.  

Oh this learning process can be hard on the brain.  Thank you in advance for any advice.

[PeakOfPerfection]

Be aware, If you guys are buying the Yamadas off EBay, I am getting more and more calls and failure reports  on these. It turns out that that some of these are are Dayton units that are over 10 years old. Yes they are "new@ but the grease and seals are dried out from sitting on the shelf for a decade. Yamada didn't warranty the last one who called me looking for help. 

[SteveC]

  Just a follow-up on my air exhaust issue.  I ended up calling Dave at Yamada and he looked up the serial number.  Just as Kevin stated, I bought mine off of ebay from a distributor that buys out old "new" stock from Graingers (Dayton pump).  This unit was produced 8 years ago and sat on the shelf until I bought it this spring.  I kinda limped through most of the season with the issue because it would happen seporadically.  I ended up getting the rebuild kit for the air motor and it worked.  FYI if you are going to attempt to do this yourself you must also buy 2 tools to complete the job.  There is also a specific torque that you must know when reassembling.  Hope this helps