Boiler feed water pump shutting down when blowing down

[123jer123]

Boiler feed water pump shutting down when boiler is blowing down, but the booster pump stays running. I believe bad pressure senior. But my coworkers believe the pump is sucking air. The booster pumps were recently replaced. so they maybe right . Any insight with this problem will be hopeful.

 

[EngrPaper]

Relatively hard to determine without pictures of the layout, but why would sucking air be a diagnosis if this only happens during blowdown? I wouldn't think your blowdown would affect the BFW tank level beyond just standard pump rate.

 

[123jer123]

Thank you for your input. I will try to send pictures of the setup. But just to be clear. You are right the BFW tank or in our case The DA tank level is not the problem. The levels in the DA never gets close to the level needed to kill the pump. And one more thing I need too add we do have a problem at high load demands with the feed water pump shutting down. That is way my coworkers believe the pump is sucking air??? But in my experience a pump sucking air will not shut down, but cavitate. and pressure will drop and stop moving or lifting water. You must start the booster pump first before you can start the feed water pump. The pressure switch makes that lets the feed water pump startup. if you stop the booster pump, the feed water pump will shut down. But in our case the booster pump stays on , just the feed water pump shuts off.

 

[LittleInch]

Impossible to guess without engineering data like P&ID / PFD or even a skethc with flows, pressures etc.

Shut down or trip on what? - Is there any indication on what tripped it? Low / high pressure? low / high flow? low / high temperature (pump or motor?) Excess amps?

What exactly happens during blowdown (pressures, temperatures etc) and why are you running the BFW pumps when you're doing that?

Is this something new? what changed if so?

 

[TBP]

Having a booster pump supplying the boiler feed pump is an arrangement that I've never seen - in my experience it's very odd. Was the booster pump installed to deal with BFP suction problems?

 

[123jer123]

This is a 800(HP) mobile boiler mounted in a trailer. This is fairly common in this type of setup. At an VA medical center. The medical center boiler plant is being redone. So we have a 500(HP) & a 800(HP) renter boilers both have this booster pumps setup. In answering your question, we have had serval mobile trailer boilers and they all had this setup. At the beginning of this thread I explain the booster pumps were worked on and this problem begin after the work. We waiting on the rental tech to test the pressure seniors to see if this is the problem Thank for the input. I will post his founding when complete.

 

[123jer123]

Found the problem. It was what I believed. A bad pressure senior

Impossible to guess without engineering data like P&ID / PFD or even a skethc with flows, pressures etc.

Shut down or trip on what? - Is there any indication on what tripped it? Low / high pressure? low / high flow? low / high temperature (pump or motor?) Excess amps?

What exactly happens during blowdown (pressures, temperatures etc) and why are you running the BFW pumps when you're doing that?

Is this something new? what changed if so?

Sorry learning how to navigate this site. Found the problem bad pressure senior. Thank you

 

[123jer123]

Having a booster pump supplying the boiler feed pump is an arrangement that I've never seen - in my experience it's very odd. Was the booster pump installed to deal with BFP suction problems?

Found the problem a bad pressure senior. Thanks

 

[LittleInch]

I think you mean sensor? Or transmitter.

but thanks for letting us know.