Pump expert help --Terry H.

Terry H.

what could cause a taco 0014 system pump to do this?

Terry H.

My first thought

was either a bearing went out or the seal went bad and shorted or over heated the housing. But on further investigation the impeller turns freely and it still runs when you put power to it.

any insight wuold be appreciated

Thanks-A-Lot

Terry H.

Aidan (UK)

Frozen?

Could the system have frozen? I've seen a large centrifugal pump split like this.

Terry H.

The lowest

temperature we've seen lately is about 60 degrees, and it started to leak on saturday. So I don't think it could be from freezing. Besides the system was running to supply DHW. Any other thoughts? Or things I should check for?

Terry H.

eleft_4

Does anyone know

Terry,


It could have frozen back when temps were low and enough crap in the housing not to leak. When the cover is screwed to the flange the crack could not open as far as your photo shows. The corrosion looks like it has been seeping for quite awhile.... JMHO





al

GW

was there any anti-freeze in the system?

Gary

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John@Reliable

Why? Look for the little things first!

Looks to me like it was a housing that was dropped or defect from factory which started as a little crack and over time water temp.& presure from expanision made it weak.Opened it enough to let crack get bigger,then showed up as a leak! Oh well new one will fix it.

Steve Ebels

Two W.A.G.S.

Could the pump possibly have been deadheaded for a period of time long enough to boil. An 0014 makes some pretty serious head for a little guy and could generate enough temp to cause a lot of pressure. Enough to crack that casting??? I don't know. The other thought comes from an experience I had with a shallow well pump. The well took a good hit of lightning and it flashed the water in the head of the pump to steam instantly. I cracked the casting in 4 different places and broke off two of the four mounting ears.

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ScottMP

WAG

My vote goes with Steve. Did'nt Paul Pollets have this problem with a pump dead heading ??

I remember being amazed at what it could do to a pump.

This had been leaking for awhile, which is why the fuzz from heating and drying is there.

Scott

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Aidan (UK)

Another possibility

The axial cracks in the pump are consistent with it having been over-pressurized, but don’t prove anything. It could have been over-pressurized by the pump being dead-headed or frozen.

If it had been dead-headed, there would have been a violent release of steam when the casting cracked and I’d expect to find bits of pump scattered around. See http://www.heatinghelp.com/newsletter.cfm?Id=43

It’s the wrong time of year for freezing; it might have happened last winter. Possible, but not probable.

The other possibility is that the system may have had no expansion capacity. If there was no working safety valve AND there was no working expansion vessel AND the pump casting was the weakest component in the system, then it could have been cracked by the expansion of the water as it heated up from cold.

I’d remove and pressure test the safety valve and check the expansion vessel. If they’re OK, I’d stick with freezing & put anti-freeze in it.

What's a WAG?

Steve Ebels

W A G

Wild A** Guess
Then there is also the SWAG........ Silly Wild A** Guess

Enjoy



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Mark Eatherton1

Another SWAG

Scientific Wild A$$ Guess.

If the system is running extremely hot, say over 180 degrees F, AND the pump is pumping towards the expansion tank, when the pump first starts up, it draws susch a low suction pressure that the water flashes to steam. I saw a power head off of a Grundfos series 200 pump get blown through two sheet rock walls and imbed itself in a cinder block wall from this exact situation. Powerful stuff that steam is...

I'd first make sure that the pump is pumping away from the expansion tank, and that there is a choke down stream of the pump to limit its' head. DHW loops can be so short that even though you are pumping away from the PONPC, the negative pressure on pump start can cause steam flash.

Let us know.

ME

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Terry H.

Gary

the system doesn't have any antifreeze in it. And the primary loop it's in has no valves that could be closed causing the pump to dead head. Could it have been a bad seal letting steam be produced in the winding of the pump?

Terry H.