I just switched from an ahs coal gun to an ahs e-140. The boiler works as planned, but I can't enough water to circulate through the radient floor pex. All the air has been bled from the pex in the floor so I don't have an air lock. I have the same circulater pump[Grundfos 15-42F] that I used with the coal gun and it worked just fine. I now have two mixing valves[Honeywell am-1 series] and only had one with the coal boiler. Do I have a big enough pump to handle two mixing valves? All plumbing between the boiler and the floor manifold is 1 inch copper. The pex in the floor is 1/2 inch, about 2200 feet.