The 1/2 inch Yamada Black Kynar Pump NDP 15 FVT has been the backbone of Apple Roof Cleaning for over 12 years. Recently, I acquired a 1/2 Inch Kynar All Flo pump. It has been on our truck nearly 15 months, doing many roofs a day, 6 days a week, and has never been rinsed out with fresh water. This is about the exact same lifespan we got out of our fleet of Yamada pumps.
Both pumps spray equally well, and both stall, every now and then, like all air diaphragm pumps tend to do.
I recently was lucky to find a 1/2 inch kynar pump from a company in Ohio called a Pumpac, and guess what ? It is EXACTLY the very same pump as the 1/2 inch All Flo. In fact, a call to Pumpac confirmed that All Flo make their pumps for them, private label!
Since the 1/2 inch All Flo failed, I stuck a 1/2 Wilden Poly pump on our truck. No, it is not a Kynar Pump, but it is a massive pump, made out of a single thick piece of solid virgin Poly. It will stay on our truck, unrinsed, to see how long it will last, w/o any rinsing.
But when it fails, most likely the brand new Pumpac Kynar 1/2 Pump will take it's place.
Yes, I have one Yamada 1/2 inch pump left. It is completely rebuilt, and ready to go back into service, but it is a wounded warrior, having been rebuilt 3 or 4 times, in it's 12 year life.
It truly is the senior citizen, of our fleet of pumps.