My question is three-fold regarding warm up:

How quickly do you allow pumps to be warmed up?  I've heard that most OEMs suggest about 100F per hour to allow even thermal expansion.  

How do you warm pumps?  I've heard about warm-up lines that bypass discharge check valves, holes drilled in check valves, and operators cracking the suction with a line to process sewer off the discharge.  How do you recommend regulating the speed at which the pump is warmed up?  

How far along in the warm-up procedure do you suggest performing a "hot alignment"?  

The heat-up rate should be specified by the manufacturer.  But, every one I ever looked up was 100