Dead-heading a circ pump

JohnNY

What happens to a circulating (centrifugal?) pump when it is dead-headed? Why?
Thanks for your help.

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ScottMP

I believe

Cavitation and over heating. The pump can actually build up preasure from the heat and steam and blow up.

In most situtations it burns out, but it can be dangerous.

Scott

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Alan R. Mercurio

Why you should never dead-head a circulator

By our host Dan Holohan

Your friend in the industry,

Alan R. Mercurio

Oil Tech Talk

jackchips_2

Don't even

have to open that one, Alan. Thanks for the memory. It's a great story and lesson in one by the master.

Mark Eatherton1

Although it's not considered a good idea...

and I wouldn't recommend that any pump be dead headed for any extended period of time, I have come across a Taco 007 that had been dead headed for 2-1/2 winters, and it was just fine.

It's the BIG pumps that you have to worry about. When dead headed, you are pouring a SIGNIFICANT amount of energy into a small amount of water and super heating it. When the pressure is dropped, the water is no longer water, but becomes steam and occupies 1700 times more space than it used to when it was water.

I once saw the power head from a Grundfos circulator that had been blown through two sheet rock walls and embedded in a cinder block wall. It can happen, but it takes time and when talking about small circulators is not as critical.

Better safe than sorry just the same.

ME

hot_rod

Why do you ask?

I have also seen, and provided the opportunity for :)deadheading small wet rotor circs.

They can take quite a beating with the discharge valve turned off! If both inlet and outlet iso's are turned off, you generally get minutes, not days!

hot rod