Our company's BFP (Boiler Feed Pump) functions to suction from the LP (Low Pressure) Drum and send it to the HP (High Pressure) and IP (Intermediate Pressure) drums. When we start the BFP, the HP discharge small MOV (Motor-Operated Valve) opens, then the BFP starts, and after 1 minute, the HP large and IP discharge MOVs open while the HP Discharge small MOV closes. I'm curious as to why the discharge MOVs open 1 minute after starting the BFP. It's worth noting that our pump is a multi-stage (10-stage) pump and it's not an inverter or fluid coupling type. There's also a Drum Level Control Valve (LCV) in the Economizer Line.

 

It is not that simple, you'll need to look at the p&id's and the controls associated with the two steam drums.
You may have a flow meter or two in the system as well.

 

Hohoim...
Welcome to Control Automation!
It may have been because there are significantly long distances between the various boilers and pumps!
Regards, Phil Corso

 

Hohoim...
I believe your Control Automation topic is a Steam-Drum-Level system that overcomes a phenomena referred to as "Swell" and "Shrinkage"!
If the Water-Flow instrument just monitors water to the steam-drum then the system is called "One-Element Control"! But, if the Water-Flow instrument is cascaded with the Drum-Level controller the system is called "Two-Element Control" !
There are several presentations in Control Automation Archives covering the topic. One is file #0590124780. A 2nd is file #1026173682. And a 3rd is file #1449379380. In all 3 of them I discuss a mathematical study relating steam-drum size to steam-drum level! Unfortunately it is no longer available!
If you want more information I suggest contacting Research Gate. They have an excellent paper, less than 3 years old!
Regards, Phil Corso