{HEAD ~ Control valves} are located at {TAIL ~ the inlet ports} to control the supply of chemical concentrates into the manifold, and the concentrates are drawn into the manifold by the operation of a positive displacement pump 
are located at
{ HEAD ~ Control valves } are located at { TAIL ~ the inlet ports } to control the supply of chemical concentrates into the manifold , and the concentrates are drawn into the manifold by the operation of a positive displacement pump
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH