Leaking Jobo "Drum Tap" Valve

[ic-racer]

Seems a common problem with older benchtop Jobo units is the leaking valve that empties the water chamber. Searching the internet for an exact replacement "Drum Tap" brand valve was not very fruitful. Perhaps the company has gone out of business.

There are many suitable replacements due to the standard size hole.

I found a 3/4 NPT valve at McMaster Carr for a couple dollars. It was a direct fit replacement.

 

[ic-racer]

My original valve started to leak quite a few years ago, but I repaired it. The plunger developed a crack. I melted the crack closed and buffed the plunger smooth again. This lasted a few years but eventually started to leak again.

 

[ic-racer]

The water bath was filled to test the new valve before re-assembly. All was well.

 

[ic-racer]

I noticed flakes of scale in the water bath recently. Can be seen in the photograph above. Since I had the unit apart, I investigated for a source of the scale.
I found nothing hiding in the pump housing and no scale on the heating elements.

 

[mshchem]

I replaced my original valve with a slightly different valve. The original valve was still floating around on the internet a few years ago, I like the one I ended up with better than OE. The original valve is from UK and has British inch standard threads

 

[ic-racer]

Actually the threads are nearly identical, I was able to reuse the original locking ring. The original locking ring is like a thumb screw and easier to tighten by hand.