Elbow riser

[hummingbirdbassist]

I just picked up a high riser mixing elbow, after chiseling out rust and other things it leaves me with a question. My elbow rusted out and it went directly down with a water tap on top, this one has a water tap on side if I'm correct, or correct me if I'm wrong. What the side hole is , this one is clogged a bit so how can I unclog it, the rest of unit water flows freely. Is this hole necessary? Can it be bypassed etc
Thank for all help

 

[runswithsisors]

I found these people on ebay. they offer an aluminum elbow that should, if not cure the problem, at the very least deter it for many years.
Mariners Marina, 6096891222
Havent tried it myself, only found them after I had replaced mine with a cast iron modle last year.