Iron Oxide Limitations With ECM Circs

Harvey Ramer

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.

The only thing that changes the volume of water is temperature. It is a hydraulic fluid that is incompressible. Unless you are talking on the atomic level and the change in volume when pressure is applied, would be so minute we would be unable to measure it.

I know for sure that a higher temp of water has a higher affinity to absorb salt. Whether the same holds true for other dissolvable solids, I'm not sure.

I know for a fact that Henry's Law is a gas law and addresses the absorption of gasses in fluids dependant on temp. As much as I have studied it, I have not come across the reference to dissolvable solids. Could you point me in the right direction. I like learning new things.

Gordy

http://www.muellerenvironmental.com/Documents/Fundamentals of Gas Solids Liquids Separation.pdf

interesting not just in closed hydronic systems.

icesailor

@Harvey Ramer:

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

I got involved in water treatment years ago. All water treatment is a PITA. I bought the equipment from my wholesaler who had been convinced to get in to it by some slug connected in some dubious way to someone else; The marriage soon got a divorce. The "owners" of the company were installing all kinds of exotic equipment where I lived and worked. I got certified by the WQA. Whenever these guys had a problem that they couldn't get to, they called me. In Massachusetts, anyone can install water treatment systems, but only a licensed Journeyman plumber can connect it to a Potable water system, get a permit and have it inspected.

They did this big house nest to a fresh water pond that had high salt levels from ocean over wash and prevailing high winds. It was also located next to an active old farm. They had been spreading fertilizer for years to grow corn. The Nitrate levels were off the chart. The water also had high levels of iron. It was a mess. So, they put in the RO system. I don't know when it was installed but they called me to install a 2 cubic foot neutralizing filter using Calcite. It was explained to me that when you RO water, you remove everything and you end up with pure water. Which tastes like crap. Then, because there are no dissolved conductive solids for the ions to feed and ride upon, the water becomes extremely aggressive. Which is why RO systems are all nonconductive plastic materials. As it was explained to me, the uncharged water would take ions from the Calcite and because of this, it would stop the metal (brass/copper) in the system from being destroyed by the pure water.

That's what I was told. I looked in to their claims. I never found anything that said anything to the contrary. They also explained that is why under counter POU RO systems are ALL non-conductive plastic.

The one thing I learned about water treatment. The more you do, the more you will have to do. There is no substitute for good water. And the unintended consequences. For example. If you have a well system that delivers iron in reasonable amounts, and a PH of less than 7.0 down to 6.7, and you put a reverse flow calcite filter (without backwash or clocks), and the iron will precipitate out in toilet tanks, bowls and other places, if you run it through the calcite filter, it will trap the iron and convert it into something (I never figured out what) and the water will have a PH well above 7.0 but below 8.0. Ion exchange water softeners don't work well with low PH water. Especially if there is iron present. Run it through a calcite neutralizing filter, and the softener sees the Iron as a form of hardness and it sees the calcite as more. The neutralizer makes the softener work better. Unintended consequences, not found in any instruction manual. You have to figure it out yourself.

Hope that helps.

I'll save the solution for women's dyed hair turning blue/green and the solution for another time unless asked.

(Or where the term "Blue Hair's) came from with old ladies.

AnthonyReikow

Steam boiler; there is a reason they need to be flushed along with the lower cutoff. Returns plug up too. Great example of Henry's Law.

AnthonyReikow

Alaska heating guys and heating folks from across the pond many times use deionized water in heating systems. Now, a chemist I'm not, but based on what my feeble mind has been able to retain from high school chemistry, and that was 45 years ago, and what I've learned from 38 years in the HVAC business, much of this makes sense to me. Also, last time I looked, most of us don't hold a Doctorate, so I prefer to practice KISS.

Dan Holohan has helped us to practice KISS.

AnthonyReikow

DJD775 said:

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.

Cold water is more dense so it cannot dissolve salt or sugar. But when heated to certain temps it can hold more but at some point it starts to come out of solution.

We have all started new systems, purged them thoroughly, prior to air scrubbers, and we would receive a call from our customer saying they hear noise in the baseboard. Where did it come from? We purged it out. It came out of solution in the form of a vapor. Some came out in the form of a solid and when we drain the same system years later we have the awful smelly stuff in black form that comes out. Minerals.

If we take untreated domestic water and place it in an ice cube tray and freeze it usually you'll have ice cubes with a white center. The minerals froze at a different rate then the water. What happens to those same minerals when placed in a hydronic closed loop system? They come out of solution and many settle in the bottom of the system. Others travel with the flow and coat the distribution piping and radiation. Remember we are talking about how these effect an ECM circ in our systems.

icesailor

There you go.

Now, if you're a true connoisseur of the extract of the java Bean, you make it with bottled water. If you really like quality java, you drink it black, straight up. No cream or sugar. That way, you can drink it hot, cold or any temperature in between. If you are in a hurry, put some ice cubes in it. To cool it off. Not just any ice cubes. You need ice cubes from a dedicated chilled plate ice machine. Not the automated ice cube tray that the give you to take up valuable space in your freezer. The ice will be clear until you notice the white spot in the middle. Water in a ice cube tray freezes from the outside in. As the water freezes, it forced all the dissolved solids and gasses in the water to the middle. Look carefully and notice the little bubbles. On a hot summer day, fill a glass with bottled water and ice cubes from a freezer tray. Take a drink, The first few taste great. After that, the water is undrinkable because of the junk in the middle. When you buy a bag of bagged ice at the Supermarket, the iice is made in machines that pump water over a freezing plate. Water sticks to the grid. Once the slab is thick enough, it "harvests" the slab. All pure water. ever been somewhere and had an adult beverage where they used bagged ice? Finished the beverage and sucked the left over ice until its gone? Bet you never did that with the ice in your ice tray at home. Put bagged ice in your coffee. Enjoy the fine flavor.

So, if you want some third world ionized water, buy bagged ice, let it melt, and pump it into the heating system. I don't know what they get for truly ionized water, but it is about $2.10 per 10# bag at the Publix Supermarket. That's less than $2.00 per gallon. Third World Ionized water. Better than nothing if you have nothing.

icesailor

Bagged Vs. Ice Tray Ice:

In this pot, there are two kinds of ice. One made in an official Scotsman plate/grid ice machine. The other ice is made in a refrigerator freezer. Which is which and which one does the owner use in his adult beverages?

DJD775

AnthonyReikow said:

DJD775 said:

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.

Cold water is more dense so it cannot dissolve salt or sugar. But when heated to certain temps it can hold more but at some point it starts to come out of solution.

We have all started new systems, purged them thoroughly, prior to air scrubbers, and we would receive a call from our customer saying they hear noise in the baseboard. Where did it come from? We purged it out. It came out of solution in the form of a vapor. Some came out in the form of a solid and when we drain the same system years later we have the awful smelly stuff in black form that comes out. Minerals.

If we take untreated domestic water and place it in an ice cube tray and freeze it usually you'll have ice cubes with a white center. The minerals froze at a different rate then the water. What happens to those same minerals when placed in a hydronic closed loop system? They come out of solution and many settle in the bottom of the system. Others travel with the flow and coat the distribution piping and radiation. Remember we are talking about how these effect an ECM circ in our systems.

General rule of thumb for solids is the higher the temp the more soluble they become and the opposite for gases. Of course when water gets too hot it boils and solids would then crash out. I'm a analytical chemist by trade and I have not come across too many exceptions to these basic rules.

AnthonyReikow

Cool, thanks for the input, but the water in a closed loop hydronic system does reach a boiling point so how is it that the minerals will separate out. Seriously, I never completely understood that or at what temperature they separate out at or how fast. All I know is that they do and settle in the system. All of what you're saying is accurate and I wish I was trained like yourself to better understand it and communicate it accurately.

Getting back to ice makers; agreed that the water gets poured, ran over a cold plate or rods, the water freezes and the minerals run off and when the run off side of the ice maker is not maintained, those minerals reek havoc on the pump, strainers and what ever else is in series with the runoff water. So there are minerals in water and yes they affect our systems and now ECM CIRCS.

DJD775

Thanks for getting me back on track. I'm thinking more of laboratory conditions and not hydronic system conditions. In high temp and pressure conditions I believe the hydrogen bonding between water molecules starts to break down and water starts to act like a less polar molecule and therefore ionic salts would begin to fall out of solution. I have to do a little research double check this theory.

AnthonyReikow

Thanks and very cool. Now, Does our Henry's law come into to play here? I was always instructed that it did. I'd hate to think I was drinking the proverbial "Cool Aid" here.

DJD775

Henry's Law is a gas law and would not apply in this case.

AnthonyReikow

Then what law is it that deals wth these solids coming out of solution?
Thanks.

Gordy

You guys are taking this to a level not seen in hydronic heating.

1. Water does not reach a boiling point in hydronic heating. In certain circumstances there is occasions where water flashes to steam in the eye of the circulator volute . Other wise we are 180 ish down to ambient. Always a moving target.

2. Most particulates are already in the fill water, or pre existing in the system infrastructure. These are solids down to a micron level.

3. The goal here is to capture those particles, and keep the system Fill water clean as possible. In particular ferrous particulates that can foul ECM circulators, and SS, AL HX's of certain designs. Fire tube types are less prone to fouling by design.

4. As far as ECM circs go there may be certain systems that prove to be beyond there use. Such as an all iron pipe gravity system.

5. We can fill flush, purge flush, chemical treat flush, chemical treat. all day long. In something like an all iron system I believe it would be a never ending cycle of treatments, and maintenance. One has to ask is the money saved by an ECM circ taken away from the extra maintenance, and treatment a system needs to gain anything the low watt circ can offer.

6. System variables in particular flow rates. In my mind an initial multi system purge cleaning, and treatment is going to be the highest flow rates the system will ever see once operational. Any contaminates there after still in the system will most likely settle out in the widest parts of the road to stay for ever. I think type of system pumping has an effect. Be it constant circulation verses on off circs, and zoning with valves, or circs. Out of the options I think a,system with varying delta p will kick up a lot more settled out particulates from the initial system cleaning at various times, and certain conditions.

As for Hot Rods system with iron ferrite particulates when none exists in system components. I think you will find that all components can be contaminated during the system build. Whether it be sanding clothes to clean pipe, or wire brushes. To just plain contamination at mills for copper. Via transportation, and handling at distribution sites down to the supplier. The bigger the system build the larger the probable volume could be. Then there is the fluid fill choice be it well,city, distiller, RO water the particulates are there just in different ppm.

icesailor

It seems to me that the harder you pump it, the higher the turbulence, and the less opportunity for anything to settle out.

AnthonyReikow

GMP= BTUH / DELTA "T" (20 Degrees) X 500. That's the Hydronic formula for determining the GPM's when using 100% water. That changes every day based on the heat loss or the load of the structure. If we move too many GPM's, we bring heat back to the boiler and short cycling occurs. If we move too little GPM's, not enough heat will be delivered and we'll get calls. If the water moves too slow through a zone we can allow air to develop in the system. If we move it too fast we risk noise and if it really moves fast, we may risk wearing away some of the metal in the delivery system. Just the flow that's needed allows for comfort and efficiency.

Gordy

AnthonyReikow said:

GMP= BTUH / DELTA "T" (20 Degrees) X 500. That's the Hydronic formula for determining the GPM's when using 100% water. That changes every day based on the heat loss or the load of the structure. If we move too many GPM's, we bring heat back to the boiler and short cycling occurs. If we move too little GPM's, not enough heat will be delivered and we'll get calls. If the water moves too slow through a zone we can allow air to develop in the system. If we move it too fast we risk noise and if it really moves fast, we may risk wearing away some of the metal in the delivery system. Just the flow that's needed allows for comfort and efficiency.

If one elects to use a delta P, delta t, or variable speed ECM circ. then those flow rates are ever changing with system demands

With delta p in a TRVed system TRVs, are modulating flows rates change.

With delta t if your trying to hold 10, 20 what ever that flow rates Is not always the same based on the load.

If your modulating the circ with the boiler output flow rates change.

In all cases water temps are a floating target when using outdoor reset.

There is a multitude of ways to incorporate these ECM circs in a hydronic design.

There are designs where flow rates are constant, but water temps are still not.

Gordy

icesailor said:

It seems to me that the harder you pump it, the higher the turbulence, and the less opportunity for anything to settle out.

True, but there has to be a fine line where particals are entrained, and still the flow slow enough to capture quickly. I think Steve got his answer long ago.

BigRob

Steve Thompson (Taco) said:

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.

Our system serving 12 condos units was a poster child for iron oxide contamination. There had been a leak at some point between 1999 and 2010. As a result a large amount of iron oxide from a cast iron component settled to the lower radiator lines, mostly plugging them. No heating contractors figured that out for years, but that is another story. The old boiler was a copper fin type, so the source must have been our previous reverse indirect Ergomax. I will try and dig up the bucket of iron oxide I purged from the lines, at that was after I had dumped a lot more beforehand. It was amazing. Besides the Ergomax, there was very little iron in the system, if any. Only PEX and brass. I plan on some PEX work to clean up a crappy section soon. Hopefully the brass components will be in good shape. I installed a SEP4 and the magnet is continually picking up particles. They must be dispersed over the 3 levels of the system. The water quality seems fine besides the particles. Once they react with O2, perhaps they are not reactive in that environment anymore - not sure. When I initially found the problem and purged the system water it was pretty foul. My plan now is to fix up a couple things and add a bunch of purge valves so I can backflow all the radiant and radiator zones, then add two rounds of chemical cleaner, then a passivisation additive. I will also descale the boiler heat exchanger. I confirmed there are no current leaks. The fill valve is shut and system pressure is solid at 12Psig. Progress is slow though..

BigRob

hot rod said:

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??

I'm going to check my radiator alpha during some future work - will post some pics if there is anything interesting. The Alpha would have been exposed to a good dose of iron oxide.

BigRob

hot rod said:

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

I can vouch for the SEP4. It is continuously pulling out particles from our system.

EBEBRATT-Ed

Are the wet rotor circulators making themselves a magnet with the pump shaft turning inside the motor windings and attracting iron particeles? The job we had problems with was a glycol system that had been diluted and run with crappy water for a long time. The mains were piped with black pipe with copper branches. Hot water system if that provides any clues

Steve Thompson (Taco)

Wet rotor circs have a magnetic rotor (yep, attracts iron particles). When we design these things we have to take into consideration the amount of fluid exchange in the rotor can (they are water lubricated by the system fluid).

Some ECM magnetic rotor folks actually filter the system fluid before it goes into the rotor can (works as long as the filter doesn't plug up).

So, us manufacturers of magnetic rotor circs test the heck out of em against iron oxide attacks and other stuff. However, in extreme cases and the right conditions they might fail (and most importantly, IF they fail due to system fluid and nothing is done to fix the water issue, they will continue to fail).

Not just iron oxide particles either - I've seen copper particle failures (copper pipe rotting due to real bad pH).

Don't panic - I've been involved in ECM product design & development for over 8 years. The percentage of failures is actually very low. I like to point out "the better the system fluid is the longer these things last" - and if one fails, inspect the rotor - it can tell the root cause...

Gordy

I would say thats about all that can be done. Be aware, and treat the issues. Best part about this thread Steve is you initiated it. Says a lot about Taco, and its Employees.

icesailor

Good Vs. Bad Ice in Pot:

I guess my photo didn't appear.

Try again.

That should do it.

hot_rod

Steve Thompson (Taco) said:

Wet rotor circs have a magnetic rotor (yep, attracts iron particles). When we design these things we have to take into consideration the amount of fluid exchange in the rotor can (they are water lubricated by the system fluid).

Some ECM magnetic rotor folks actually filter the system fluid before it goes into the rotor can (works as long as the filter doesn't plug up).

So, us manufacturers of magnetic rotor circs test the heck out of em against iron oxide attacks and other stuff. However, in extreme cases and the right conditions they might fail (and most importantly, IF they fail due to system fluid and nothing is done to fix the water issue, they will continue to fail).

Not just iron oxide particles either - I've seen copper particle failures (copper pipe rotting due to real bad pH).

Don't panic - I've been involved in ECM product design & development for over 8 years. The percentage of failures is actually very low. I like to point out "the better the system fluid is the longer these things last" - and if one fails, inspect the rotor - it can tell the root cause...

Yes, the key is don't avoid ECM technology, and most important pay attention to fluid quality.

I've recently heard that iron ferrite is something like 10X of limescale as far as putting the damper on heat exchange.

You REALLY don't want it (iron ferrite) in any part of your system., even if the circs can handle small levels.

It's a very tough product to get out, almost like a thick ink or paint, not really a particle you can get a hold of and separate easily. And in large quantities you would need to service the separator on a regular basis.