Iron Oxide Limitations With ECM Circs

Steve Thompson (Taco)

Fellow Wallies, I'm ashamed to ask but have any of you seen anything published that states the maximum allowable amount of iron oxide in a system when using ECM circs? I assume PPM.

10 years of experience with ECM - I have still not seen anything published on this. To date, all I know is too much will cause issues (duh).

Robert O'Brien

I have never had an ECM of any brand fail for any reason, I think this whole water quality thing is much ado about nothing

Steve Thompson (Taco)

Agreed ECM failures are extremely rare but I've personally seen all three brands fail due to excess iron oxide. Possible that's why there is no limit published.

FranklinD

Ever since installing my BumbleBee I've been curious about this. I wouldn't be surprised to find that I have a higher than 'normal' amount in my system. I'll be curious to see how things look when I repipe some things in the spring.

EBEBRATT-Ed

I don't claim to know much about this but I did see two new (grundfos) pumps fail on the same job. We ended up installing a fine bag filter on the job. Someone told me later that you can install a device with a magnet in the pipeline to catch the magnet particles.

FranklinD

Excellent idea. We install good sized magnets in all the 'wide spots in the road' on all our heavy equipment hydraulics, transmissions, and engine oil coolers, along with secondary filter systems.

That's something I'll have to look into for my repipe. I'm not too keen on any sort of filter, but a nice magnet secured in the piping to the boiler...that I could do.

kcopp

Robert O'Brien said:

I have never had an ECM of any brand fail for any reason, I think this whole water quality thing is much ado about nothing

I hope you are right Robert.... Time will tell. I just had 1 SS boiler that I not service that may very well have been due to water issues...specifically iron. Looking at the UK they are having issues there w/ there market.

hot_rod

Good questions, I'd look to then folks in the UK the issue started showing up there first due to all their open systems. A lot of the magnetic separation products were developed there, Fernox, etc.

We have a growing collections of pics sent to us of failed, or rotation error ECMs. Here is one of two from our own shop that started seizing and showing rotation errors on the display. Took it apart myself..

We also get pics from installers of the magnetic particles that the mag separators "suck" out of the systems, it is a real concern.

The symptom is easily addressed with magnetic separators, probably see a bunch more at AHR.

My bigger concern is WHY so much ferrite in supposedly tight systems. It took ECM to bring the issue "out of the closet" But it doesn't take a lot, really to jam a circ, maybe a 1/2 teaspoon on this one pictured.


Our shop is all alu pex, copper steel and stainless boilers??

Snowmelt

Wouldn't you want to also use Sentinel as a cleaner and an inhibiter?

kcopp

I do think water quality is going to be a concern w/ the new modcon boilers vs. the older CI blocks.
here is an opinion from the UK....
https://www.youtube.com/watch?v=JhiAgjLYn2M

DJD775

Out of curiosity why are ECM circulators more prone to failure due to iron oxide than traditional circulators?

bmwpowere36m3

DJD775 said:

Out of curiosity why are ECM circulators more prone to failure due to iron oxide than traditional circulators?

I don't think anyone has made that statement… the question was posed whether its the case.

However I'd wager "traditional" circulators are more robust to contaminants, like old CI boilers vs. Mod Cons.

Harvey Ramer

bmwpowere36m3 said:

DJD775 said:

Out of curiosity why are ECM circulators more prone to failure due to iron oxide than traditional circulators?

I don't think anyone has made that statement… the question was posed whether its the case.

However I'd wager "traditional" circulators are more robust to contaminants, like old CI boilers vs. Mod Cons.

6 and 1/2 dozen of the other. Traditional circs have weaker magnets in them then the powerful ECM circs, therefore they attract less iron particles. The ECM has a higher starting torque, therefore won't get stopped by the particles as quickly.

The most common place that I see circs seized up is on those open, outdoor type wood boiler systems. On one such system, I have both the Alpha and the Bumblebee installed. The Alpha has seized up, the Bumblebee has not yet seized up. The Bumblebee has 2 things going for it to help address this issue. They have a screen to try to keep the particles out of the rotor and they also go to full power at startup for a brief period of time. I would contend that those features are helping.

In the meantime I keep trying to sell water quality treatments as an alternative to emergency no heat calls. Some people buy it, some don't.

I really have no idea of the PPM of iron in these systems. I'm going to start checking though because I'm curious as well.

Bob Bona_4

Interesting topic. The only ECM pump that's failed me so far in the last 4 years is an Alpha that took a hit from a power surge thanks to Sandy.

hot_rod

True the pump manufacturers are addressing this potential condition.

Maybe a screen will slow then problem, I think IF you have iron ferrite in the system the screen will just plug eventually and move the problem. The stuff i have removed is a powder consistency. Take a pocket knife and sharpen a pencil, it's that type of consistency.

I have seen wet rotor circs fail at then rear bearing from lack of system fluid to keep it lubricated. Install one with the motor facing straight up, with an air bubble trapped, and see how long it will last. It needs to be fluid lubed.

It's no different than a Y strainer, once the strainer plugs, all the components it protects will feel the effect.

I'm not blaming the pumps it a fluid related problem, been in some systems since the entrance of PE tube is my suspicion. It just didn't present in the PSC type motors.

Fluid conditioners with the correct "package' could be part of the solution. Oxygen scavengers are intended to prevent the formation of the iron ferrite. Coating any ferrous components with the film provider component in hydronic conditioners should help. These chemicals will need to be checked and maintained, and boosted from time to time, especially in the open OWF devices, they suck. O2 that is.

Any time you pull a circ from the volute, scratch the impeller deposit with your knife. If it sticks to a magnet, guess what!!

Fluid quality will be the next "big" think addressed in our industry. It needs to be.

Steve Thompson (Taco)

Wow - good posts guys. Couple of observations...

100% correct excessive iron oxide is probably a bad sign - systems rotting out from the inside out - probably caused by excessive air (but could be a PH issue or excessive water velocity). Challenge is what is excessive oxide

The only magnet in a non-ECM circ is the magnetic field the stator generates that grabs the "nails" in the rotor, causing the rotor to spin. BTW, iron oxide will cause premature sleeve bearing failure in std wet rotor circs (it's abrasive). Same goes for mechanical sealed circs (premature seal failure) so this awareness is not only for ECM. I just don't like the idea the ECM circ becomes a sacrificial anode, collecting the iron kind of like a magnetic dirt separator.

I'm not an installer but it kind of makes sense to me the better the system fluid the better the system (longer component life and better heat transfer medium).

I've reached out to some of my contacts overseas and will let you all know what they say. ECM's have been around there since 2001 so they have 5 or 6 years of experience ahead of us.

Harvey Ramer

If we started collecting rain water and using that in our systems, all these problems would go away.

But then our low water cutoffs would likely have to be rengineered.

hot_rod

Rain water, possibly, depending on what that rain travels thru on the way down Ph around 6 for average rain water, may still need to add some buffers to it.

Harvey Ramer

True that. PH buffers are easy and inexpensive though compared to deionization or reverse osmosis.

It's a novel thought, but I, not unlike most others I assume, don't have the time to fool with it.

SWEI

DJD775 said:

Out of curiosity why are ECM circulators more prone to failure due to iron oxide than traditional circulators?

Conventional wet rotor circs are built using PSC motors, a type of single phase induction motor. Induction motors do not have permanent magnets in them.

Gordy

Maybe magnetic dirt separators need to be a required system component like an x tank.

Are the dirt mags actually doing a good job. I mean getting iron out of a magnetic dirt sep on a system says it's working, but is it capturing everything? How many laps in a system does super fine iron oxide need to make before its trapped. Maybe more powerful magnets? Maybe a length of piping that's removable for cleaning with a magnetic shell 12" long right before the circ. Just thinking out loud of increasing magnetic surface capturing area. Vortex method is good, but I think suspended fine particals sneak by.

DJD775

SWEI said:

DJD775 said:

Out of curiosity why are ECM circulators more prone to failure due to iron oxide than traditional circulators?

Conventional wet rotor circs are built using PSC motors, a type of single phase induction motor. Induction motors do not have permanent magnets in them.

I never thought about the permanent magnet, makes sense.

FranklinD

Gordy: That's exactly what I was thinking -- a chunk of removable pipe with a magnetic shell around it.

The only other thing I can think of that I would be able to implement easily with equipment I already own is this: A high flow/low head screw-on filter (such as we use on constant-duty heavy equipment cooling systems) with isolation valves and an air bleeder. I'll have to check out the actual filter specs and info, but I know they're rated up to at least 300* F and 75 psi. Just don't recall if they're paper elements or some kind of mesh. The filter adapters we use are generally piped for 1" or 1-1/4" NPT with a mounting plate, with the filter screwing on from below. The filters themselves are about 18" long and 5-6" diameter...and pretty cheap in the grand scheme.

Then again, a good dirt mag would probably be cheaper and better in the long run anyway.

I might be way out there on this one...just happened to think about it while reading through new posts. I know for a fact that despite flushing and cleaning, there's still a fair amount of crud floating through my system, and god-knows-what settled into the bottoms of my 100 year old radiators. Given the option to have one installed originally, I definitely would have...unfortunately, like many, the bulk of my HeatingHelp education came after the fact (ha).

Gordy

Filters would cause to much head loss to the system, and a moving target as filter gets filled. The vortex seperaters do not add hardly any head to the system. The pipe with a removable magnetic shell would not add any headloss until the pipe walls start collecting a fair amount of debris. But you could up the pipe size one or two, and create more surface area to collect, slow velocity a tad through this wide spot in the road, and probably get by for quite a while before needing to remove, and clean.

Harvey Ramer

Gordy,
If you had a magnetic she'll that all the fluid passed through, wouldn't that magnetize the iron/steel particles and cause them to stick to any steel in the system?

I think fernox has a good idea with their sheathed magnetic rod that inserts the full length into the center of the fluid stream.http://www.fernox.com/equipment/filters/tf1+total+filter

Gordy

Harvey Ramer said:

Gordy,

If you had a magnetic she'll that all the fluid passed through, wouldn't that magnetize the iron/steel particles and cause them to stick to any steel in the system?



I think fernox has a good idea with their sheathed magnetic rod that inserts the full length into the center of the fluid stream.http://www.fernox.com/equipment/filters/tf1+total+filter

Yes You are right Harvey. I'm just thinking out loud is all simple, and cheap. I guess you would have to isolate the pipe section with something non ferrous, if it were ferrous piping, and hope for capture on the first pass.

hot_rod

The Caleffi dirt cal products will take down to a 5 micron particle within 50 passes. The magnet is an extra protection intended to catch small particles on first pass

It would take a very fine mesh to get to that protection, and need frequent cleaning. Separators cause the particles to fall down out of the flow. We have done extensive testing to get confirmation that we can catch those small particles

Gordy

Thing is 50 passes later the ECM circ gets its share no? I guess when dealing with old systems it comes down to what's there. Old gravity, old copper where the boiler, and circ may have been the only ferrous components?

hot_rod

That's why everyone is looking at the mag sep add on. Grab as much as possible first trip. We put X amount of ferrite in a circuit and measure what collects.

Still the best plan would be to treat the problem, not the symptom. Why are we seeing the iron ferrite. Has it always been flowing around the systems? I've really never looked for it until it started showing up in permanent magnet circs.

One thing to remember about vortex separation, it takes some fairly high velocities to make them work. We built a clear plastic version, connected to a Grundfos Magna so we could dial in exact flow rate Connected the ultrasonic flow meters to confirm.

As we see more and more variable speed circ on both side, boiler and distribution, the ability to use vortex separation efficiently may be in question. Or perhaps program the pumps to assure high velocities for certain periods of time, then modulate.

Having built clear samples of both, no question the media type seperators are amazingly effective from very low, to well over the normal velocities you would expect to see in typical hydronics. We run 'em out to 10- 12 fps on the test bench

icesailor

@Steve Thompson (Taco):

For what anything is worth, I once read a book by Stan Grayson about old one cylinder gasoline marine engines. Which were the next generation of steam engines except some smart dude figured that you could use the expanding gasses of gasoline without the added weight and complexities of a steam boiler. They also used these same engines on fresh water lakes. Today, if you can ever find a working make or break engine, it came from a lake. Because all the marine engines returned to the state they started out. Powdered iron.

It is said that iron is the most common element in the earth. It is not found in the form of a cast iron circulator or engine block. It started out as a powder or some other form. It has to be refined to turn it into cast iron or steel. It can be recycled. The town I lived in on Cape Cod had a terrible problem with dissolved iron in the ground. So much so that the end of the town I lived in, had all wells with high iron in the water. They put a municipal well system in near me and had to spend millions of a manganese greensand filter to oxidize the dissolved iron into a solid so they could filter it out. My water was clear as a bell but you could taste the slight iron taste. The water was slightly acidic with a PH of 6.7 or 6.8. I installed a whole house 2 Cu. Ft. calcite flow through neutralizing filter with raised the PH to over 7.0. Before or after, I never got any rust slime in the bottom of a drinking glass left out overnight. My heating system was filled with the untreated water before I moved into the finished house. I don't think I ever completely removed the water from the system. I sold the house in June of 2013. The water in the system turned redder and redder with age. The iron was already in the water when it was installed. I've seen that same calcified plaque iron on circulator impellors where there was no flow, stuck on surfaces. (my thing about impellor cavitation) and inside some circulator volutes. If anything is out of the ordinary, I noticed it. With water well pumps that pumped in high iron locations, you would see that same calcified hard iron on the low flow parts of brass impellors and especially around and on Bakelite impellor diffuser covers. I saw it on Stainless Steel water pumps. The common denominator to me was the presence of iron and vast amounts of friction which probably create vast amounts of static electricity, that was doing a form of electroplating to surfaces. My heating system was a cast iron boiler with a Taco 007 until I changed it to a Wilo ECM. If I drained the water from the system, the rust was still in the water when I filled it back up. It coated everything.

Getting back to the old one lung marine engines. They failed because the salt water sets up a very good environment for the cast iron to change to what it was when it was in the earth. A powder. Rust on steel bridges or cars is just Cast Iron in a state where it can go back into the earth.

Personally, without any educated expertise. it would be interesting to see what magnetic separation collectors would do in a closed heating system. There are already many, many other magnetic sources in a heating systems. What's another?

Here's another example of what I am saying.

The two units to the East of me, developed low water pressure in their units. One was unoccupied, the one next to me was. The City came and futzed around with it and decided that it was "Calcified" or had "Calcium Build Up" at the Corporation Cock at the main. So, a few days later a large gang showed up to fix it. Let me say right out, that I have paid my dues for many years, playing earth Guitar in the Dirt Band. Where I came from, and the band I played in, this work was done by one or two musicians. Playing 5' Banjo's. This job required a mini-excavator and 6 men. two as arguing supervisors. Eight if you count the two that came on a Saturday to gig it up, decide it wasn't the curb stops, (4" from the main) and fill in the hole They ripped out everything in sight except for any rubber roots with the copper core. When they got down to business after the destruction, the main was 2" Sch. 80 PVC pipe with a Cast Iron clamp on saddle fitting, a brass Corporation cock, brass adapters, and then to Poly Pipe. The "Calcification" was in the cast iron adapter that made the connection to the 2" PVC main. The "Calcification" is from the iron in the water which the city adds something to encapsulate the iron in the water and lots of chlorine to kill critters. Where I'm from, they would have poked a beater screwdriver in to the obstruction and let the rust particles flow out with the water.

The only dis-similar metals were the Cast Iron saddle adapter and the brass Corporation Cock.

It took 30+ years to occlude.

Don't they use Iron Oxide for some forms of sand paper?

SWEI

We put a high flow 20µ pleated paper filter (Big Blue 20") in the return line to the purge cart (after the open flush and before the boiler is fired.) The amount of crud that comes out of old systems can be quite impressive. Once that is running clean (typically an hour or two) we let the DirtMag do its job.

AnthonyReikow

Anybody ever hear of "Henry's Law"? Water can hold "X" amount of dissolved solids in solution. But whe you heat water up, those undisolved solids come out of solution in the form of a gas (air in the system) or solids (sludge, dirt and sludge) in the system or boiler. Henry's Law is always at work in the system especially more pronounced when you fill a system with fresh water. Now let's mix some dissimilar metals in the system connect by water and you get electrolysis and electrolysis creates acids. These acids break down the metal in the system and "Wa La", iron oxides and lots of other stuff. We all know soot in the heat exchanger cause a loss of efficiency. We need to ask ourselves if this stuff we created in the water side of the system acts like soot in the heat exchanger and the answer is YES. We make heat efficiently and transfer the same into the water, the water gets moved by the circ but it can't get out of the pipe due to the coating created on the inside surface of the pipe. Fernox has proven this with many studies. The have a solution. You can clean the system with the cleaner, treat the system with the inhibitor and if the system is real big or has lots of stuff in it, they have a machine with a very nice size motor on it to speed up the process. Then there's the TF1 bypass unit that has a magnet in it to help us remove iron oxide.

Fernox has proven that if you install a new 90+% boiler in a system that hasn't been cleaned and treated, that boiler can end up in the high 80's % efficiency range and you'll never get it back with out cleaning and treating.

Food for thought: the next time you install a new high efficient unit, ask yourselves this knowing what's being created in the system, have we really helped our customer.

If an ostrich is being chased by a lion, and the ostrich does what it does when stressed and sticks its head in the ground, does the lion stop attacking and go away?

Please do not think for one minute that this water quality issue is just a bunch of "hogwash". It's real and we should have been looking at this years ago.

Harvey Ramer

AnthonyReikow said:

Anybody ever hear of "Henry's Law"? Water can hold "X" amount of dissolved solids in solution. But whe you heat water up, those undisolved solids come out of solution in the form of a gas (air in the system) or solids (sludge, dirt and sludge) in the system or boiler. Henry's Law is always at work in the system especially more pronounced when you fill a system with fresh water. Now let's mix some dissimilar metals in the system connect by water and you get electrolysis and electrolysis creates acids. These acids break down the metal in the system and "Wa La", iron oxides and lots of other stuff. We all know soot in the heat exchanger cause a loss of efficiency. We need to ask ourselves if this stuff we created in the water side of the system acts like soot in the heat exchanger and the answer is YES. We make heat efficiently and transfer the same into the water, the water gets moved by the circ but it can't get out of the pipe due to the coating created on the inside surface of the pipe. Fernox has proven this with many studies. The have a solution. You can clean the system with the cleaner, treat the system with the inhibitor and if the system is real big or has lots of stuff in it, they have a machine with a very nice size motor on it to speed up the process. Then there's the TF1 bypass unit that has a magnet in it to help us remove iron oxide.

Fernox has proven that if you install a new 90+% boiler in a system that hasn't been cleaned and treated, that boiler can end up in the high 80's % efficiency range and you'll never get it back with out cleaning and treating.

Food for thought: the next time you install a new high efficient unit, ask yourselves this knowing what's being created in the system, have we really helped our customer.

If an ostrich is being chased by a lion, and the ostrich does what it does when stressed and sticks its head in the ground, does the lion stop attacking and go away?

Please do not think for one minute that this water quality issue is just a bunch of "hogwash". It's real and we should have been looking at this years ago.

I was under the impression that Henry's law deals with gasses, no?

Everything else I agree on.

There is another alternative to chemical treatment that I am in favor of. That consists of deionization of the system water. This will lower the TDS and the conductivity of the fluid. Then a sacrificial anode is placed inline. Elysater has good information on this technology.

Paul48

Some of the hydraulic valves we deal with at work, can't handle 5 micron particles. I know, it's a different animal,but enough of those particles, and you have a problem. We use a filter with a bypass indicator. The pump can't be dead-headed. Something like that would be childs-play for Caleffi engineers. The whole package... a DirtMag pre-filter with a secondary filter w/ bypass(pop-up indicator).

Gordy

I agree with Harvey on Henry's Law. It does not apply to solids.

icesailor

If "Deionization" is anything like RO, it's my understanding and experience (in plumbing) that you open yourself up to a multitude of unintended consequences.

"Henry's Law" explains a lot of the unexplained for me.

They stick this clip on your finger and it can tell the O2/Oxygen level in your blood. There are parameters.

If water consists of one part Hydrogen, and two parts Oxygen, there must be a Oxygen Parameter in water, We know that water can hold varying levels of dissolved oxygen. If oxidation of metal is caused by Oxygen, is there a minimum level of O2 in water that helps slow down oxidation?

If the oxygen levels in a pond level are decreased below a certain level, fish will die. Same if the levels become too high.

My wife's horse is sick. Last night it was getting an IV. I noticed that there was a water level in the drip tube. They added another upper bag to get the flow to speed up. The level went up 3/4" in the drip tube. There were air bubbles from the old level down, and none to the new and higher level. Where did the bubbles come from? Its a closed system. The IV bag has to be high enough to overcome the blood pressure in the body. It can't run backwards. I'm curious. About such things.

Were the bubbles from the water? Or from Oxygen being forced through the clear plastic tube like it is supposed to happen with non barrier PEX tubing?

Harvey Ramer

icesailor said:

If "Deionization" is anything like RO, it's my understanding and experience (in plumbing) that you open yourself up to a multitude of unintended consequences.

What are those unintended consequences Ice? Keeping in mind the system being closed loop with a sacrificial anode and/or a PH buffer.

AnthonyReikow

Henry's law states that when a fluid is heated it holds less dissolved solids. Bottles law deals states that when the pressure increases, the volume decreases which is why a diaphragm tanks is used in a system to accept the expansion of the water when heated. Check the web for both Henry and Boyles Law. It applies to what we do everyday.

Deionized water is cool and helps tremendously but only helps. Corrosion can still occur. Inhibitors help in addition to but need to be checked at some interval.

DJD775

AnthonyReikow said:

Henry's law states that when a fluid is heated it holds less dissolved solids. Bottles law deals states that when the pressure increases, the volume decreases which is why a diaphragm tanks is used in a system to accept the expansion of the water when heated. Check the web for both Henry and Boyles Law. It applies to what we do everyday.

Deionized water is cool and helps tremendously but only helps. Corrosion can still occur. Inhibitors help in addition to but need to be checked at some interval.

So if I wanted to dissolve salt or sugar in water it would go into solution easier if the water was cold? I don't think so.

Tim McElwain

If memory serves me I think folks at Mestek when they came out with the KN series of boilers (cast iron condensing) and the Ray (also cast iron now the KN2) they had done some work on iron content in the water.

Gordy

Maybe another gas law? There are several to choose from. Charles', Gay Lussac's, Avogadro's, Graham's,Dalton's, Combined and Ideal??