I have one pump in the radiant heating system that does not have a big enough entry hole to attache the wires with 3/8" flex conduit. It is equipped from the factory with plug-in cord.
The pump is not controlled via switching the 120V line. It is a remote sensing variable speed pump.
Is it allowable to simply put an AC power box near it and plug the pump in?
If it has an a/c plug, my guess is there should be no problem just plugging it in. As is true with most of these pumps, the bearings are usually water cooled/lubricated - don't run it until the thing is sitting in the pipe and water filled.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013