impellers disappearing on small taco pumps

Steve Eayrs

Have a couple places where the taco 005, 007 cartridges have to be replaced about every year or more. Upon inspecting the pump, there will be nothing but a shaft left. I have thought it was due to a ungrounded electric problem of some sort, since that is what I heard once, but how can this affect the teflon, (or whatever it is?) impeller. Have never found an electrical problem on these system. One place replaces at least one cartridge every 6 months. They have about 8 pumps total, with aprox. 1/2 of them on the boiler side (have 4 boilers) and the other 1/2 on the dhw side.
It has not been just restructed to dhw purposes with the 005 brass or stainless pumps, as I once thought, but does seem to more prevalient with them.

Any thoughts?


thanks, Steve

ScottMP

wow

I am stumped.

Do they have zone valves ? Could they be dead heading ?

It seems like a velocity problem, do any of the pumps burn out ?

How about strainers ? Any debris in the system water ?

Can't wait to here the other opinions.

Scott

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B. Tice

missing impellers

I have heard of this happening in systems where there was alot of debris floating around.

John@Reliable_2

Taco impeller

I have found this before, and found the real problem to be Hi-Limit on aquastat out of cal. letting water temp. get up over 220*. If I was you this is where I would look. The impeller will start to break apart from the outside and once this happens the fins will go away real quick as they have no support.Hope this helps John@Reliable

Art Pittaway

Eaten by Munchkins...?

Ooooooh,I know that was bad but it had to be said!

Sorry, Art

munchkin-man

Circulating pumps in general have been doing this for years

with brass, bronze meatal, and plastic impella's. I do not think for even a blink that the Munchkin is the direct cause of the impella failures. I suggest all do home work on circulator impela failure. I WOULD THINK THAT ANY OF THE CIRCULATOR MFG'S WOULD HAVE INFO ON THIS. If the proper circulator is used on the Munchkin it is not the Munchkin causing the failure.

As stated high water temperature can be a major plyer in the impella failure. If used on domestic for what ever reason the level of total disoved solids TDS will cause deterioration of impellas over a period of time. The suspended minerals act as an abrasive and eat them up. Cavatation can also assest in the cause of deterioration.

Just follow the water way road perhaps your impella will get eaten on the way.

Steve Eayrs

In most cases there has not been

zone valves. Some systems are not that clean, but not bad, and at least 1/2 on the dhw side, w/ city water.
Also their is a redundant high limit control, and it would shut the burner down before it reached over 200 deg. Operating aquastat on high side is 180.
I would think I would be getting peices of the impellers stuck in check valves, etc., but they evidently..... disolve?
Steve

Steve Eayrs

No Munchkins involved here!

No muchkins to be found.......I've never been on that yellow brick road, and my dog is not named toto.
Same city water runs many other pumps with no problems, so I somewhat ruled out the water conditions.

thanks for the comments, Steve

ScottMP

Jeff

I think he was kidding.

Scott

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Art Pittaway

Scott, I gotta learn

how to make these things, and use them, ;?) , (:0) , :-D , much to serious otherwise...!

Art

hot_rod

Cavatation

would be my first suspect. Possibly high chlorine content water attacking the plastic impeller?

Try another brand of pump with a stainless impeller if it's a water issue. If it is cavatation, fix it1 Even a kyprotonite impeller will be compromised by a cavatation problem

Check for operating air eliminators, restrictions on the pumps inlet side, plugged strainers etc. Look for hidden strainers like the Jomar filter ball valves used on many Heatway Hydrocontrol panels. Those are real pump killers! Read the article below for more ideas.

http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,4270,00.html

hot rod

munchkin-man

(: (: (:

I know I just like to help explain thing as best as possible so all are up to speed on modern products and of couse the Munchkin. I know he was foolin thats why I said follow the water way road. Thanks guys

(:

Glenn Harrison

I've had this happen to...

a couple of customers that had Lennox "Complete Heat" units. These units are similar to a Polaris. They just Heat water and provide it for domestic and space heat. They have a Taco 005 Bonze pump that just recirculates the water between the top and bottom of the tank. All I can say is it must have something to do with the quality of the water, as these units have no checks or valves in the pump circuit and no head to speak of. After that, I don't know what is doing it.

Glenn Harrison, Residential Service Techician

Althoff Industries, Crystal Lake, Illinois

Althoff Industies Link

hot_rod

Regarding DHW side pumps

Water softened to near zero, add to that temperatures above 140 degrees, throw in some dissolved O2 and CO2, maybe leaning to the acidic side, and you have a water that is very aggressive to brass and copper. Water in areas of NJ and area of New England can have high levels of CO2. Soft water with CO2 of 15ppm, ph 7 or lower, & low mineralization can actually pull traces of copper causing the green water staining (cuprosolvency) sometimes seen on bath tubs or sinks.

If the pipe and pumps were allowed to form a surface or coating first, you would better protect the materials.

Elevated pressures also compound this problem as they tend to keep the O2 and CO2 in solution. Of course velocity would also play into the formula. Obviously the impeller is in a prime location to be effected by all these issues.

Dealloying or supercalafragalistic dezincification (I made up the first part of that term) will cause certain brass or bronze alloys to lose their integerity, pin holes or erosion. Again water high in O2 and CO2.

It's always the water.

hot rod