Hi, so i recently bought my first truckmount. Its a used prochem legend se with 2,900 hours and operates well. The water pressure is constantly pulsating and i am having trouble with is the chemical pump injection system. The dwyer meter has tons of air bubbles and tries to purge but wont completely do so. I replaced the diaphragm in the chem pump and checked the checkvalves. Then put that back together and am still haveing the same issue. Id be grateful for any feedback.