Yoopersup, how do you know it complies with NFPA/NRTL regs? Personal experience with the particular model?

To me such wording as the email used is always a big red flag:

"This construction does comply with NFPA-20, UL-218 and FM-1321/1323 fire pump
controller standards."

It does comply? So says who? "NRTL Listed to standard XYZ" is the type of wording I would find more reassuring. I've seen all sorts of equipment that is "designed to meet" or "complies with the requirements of...", that has never been certified by an OSHA-regulated NRTL or other industry-recognized body. In some cases, as inside your own Listed end-use product, it may OK (but more complicated) to use such unrecognized parts.