The bottom line is that the pump has a substantial effect on system performance; if it’s not working, nothing is going to happen. Of course, sizing, selecting, and installing the pump are all critical aspects if a system is going to work well and keep operating costs to a minimum. But configuring the pump correctly is another factor that can determine whether or not a system operates as planned.
Like designing and installing any hvac system, it’s all in the details. It’s best to do it properly the first time to avoid problems down the line.