There are several ways to model this situation.

<font color="#0000ff">Without the Pump</font>
In this case, just model to the pump flange, and call it an anchor. In this situation, you wouldn't need CNODEs.

<font color="#0000ff">With the Pump</font>
This case requires that you model the pump as a series of rigid elements, down to the base, which is then anchored. At the pump flange, you simply transition from <em>pipe</em> to <em>rigid</em>. You really don't need CNODEs in this instance either.

Including the pump allows you to connect the suction and discharge lines, and obtain an overall graphical representation of the system. However, assuming the pump is rigid, and acts as a point of fixed support (i.e. an anchor), the lines will not affect one another, so running both together isn't necessary.

<font color="#0000ff">With CNODEs</font>
A CNODE can be thought of as <em>an association of Degrees of Freedom</em>. In essence what you are telling the software is that the "X" DOF for node 123 is the same as the "X" DOF for node 456. You typically use this technique to connect pipe to nozzles or structural steel, and expansion joint tie-bars.

A CNODE is treated as an <em>internal restraint</em>. Because it is a <em>restraint</em>, the loads on the CNODE appear in the restraint report.

One <em>trick</em> some users employ is to connect pipe to pump flanges via a CNODE. This then shows the loads on the flange in the Restraint Report. This isn't strictly necessary, because you can always get the loads from the <em>element force report</em>.

I hope this helps.