We've seen that before. A previous manager bought a few pumps online to save money. They were meant to be genuine Graco pumps, but when we had to service one, we found the diaphragm was a cheap knock-off. It didn’t have the same flexibility as a real one, which caused the pressure drops. It was a false economy. In hindsight, we should’ve stuck to more reliable sources—like the ones listed in this post I found, which highlights trusted Graco distributors.
